JIMMA UNIVERSITY

JIMMA INSTITUTE OF TECHNOLOGY(JIT)

MAINTENANCE METHODOLOGY TERM PROJECT BY STUDENTS OF BIOMEDICAL ENGINEERING

Studentsrsquo name ID NO

1Keneni

Bentihelliphelliphelliphelliphelliphelliphelliphelliphellip0049902

2Birhanech Workuhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip0021802

3Abdulmelik Adiluhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip0002402

4Shibre Gerremewhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip0071202

5Zelalem Yigzawhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip0090303

Submission date 02062012

i

AbstractThe intention of this project is to have deep understanding of special biomedical equipment called steam autoclave It is an instrument used to sterilize microbiological life which exists on surgical equipment Every company producing this device has its own manual for installation maintenance and operation of the device Without reading this manual one cannot simply make the power ON since the device is too harmful and it has complex electric circuit which may cause shock if not properly operated The thing that motivates us to do this project on steam autoclave is due to such electric shock and contamination caused by the operatorrsquos error Therefore it is aimed at minimizing this and other problems concerning the device

Acknowledgement

We would like to thank our instructor AtoWondimu Fanta for his unexplainable moral support and encouragement towards this project We also show our gratitude to our friends and all who supported in one way or the other for the completion of this project In addition we would like to thank jimma university for providing full internet access for us to complete this project Finally we want to say thanks for God who made all this possible

ii

Table of contents

1 Chapter one pageIntroductionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip1Back groundhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip2Problemrsquos statementhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip2Objectiveshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip3TheMain topics of maintenance methodologyhelliphelliphellip4

2 chapter two Operational principles of steam autoclavehelliphelliphelliphelliphelliphellip7Technical specificationshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip7Sterilizing processhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip8Controlling partshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip9Methods of using steam autoclave helliphelliphelliphelliphelliphelliphelliphelliphellip9Schematic diagramhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip10Accessorieshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip11

3 Chapter threeInstallation of steam autoclavehelliphelliphellip11Items for autoclavinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip12Loading an autoclavehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip12Unloading an autoclavehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip13Quality controlhelliphelliphelliphelliphelliphelliphelliphelliphelliphellip14

General procedureshelliphelliphelliphelliphelliphelliphelliphellip154 Chapter four

Maintenance and troubleshootinghelliphelliphelliphelliphelliphelliphellip16Corrective maintenancehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16General preventive maintenancehelliphelliphelliphelliphelliphelliphelliphellip17

iii

Troubleshootinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip19

5 Chapter five

Result and conclusionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

Recommendationhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Appendices helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Lists of figures

1 figure1 schematic diagram of autoclave

2 figure2 maintenance cycle

lists of tables

1 table 1 autoclaversquos capacity

2 table 2 troubleshooting

3 table 3appendices

iv

CHAPTER ONE

Introduction

The machine described in this project is a steam autoclave sterilizer that has beenspecially designed to sterilize most of the materials and instruments used in dental surgeries doctorssurgeries and hospitals in generalThis project contains general information pertaining to autoclave operation and is to be used as a general referenceWhen performing autoclave operations all procedures must be performed in accordance withthe specifications provided by the customer and in accordance with federal provincial andmunicipal safety legislation and company procedures safety rules and regulationsThe operating cycles can be monitored by means of the pressure gauge warning lights and by theposition of the controlsAn autoclave is a specialized piece of equipment designed to deliver heat under pressure to a chamber with a goal of decontaminating or sterilizing the contents of the chamber Decontamination is the reduction of contamination to level where it is no longer a hazard to people or environment while sterilization is the total destruction of microorganisms presentThis is achieved because heat damages the cellrsquos essential structures including the cytoplasmic membrane rendering the cell no longer viable This will only occurs if the material is heated to the specific temperature for a given period of time These parameters will vary depending upon the nature of the microorganisms present and the characteristics of the load itselfTo facilitate this transfer of heat moisture is often added but this does not guarantee success A number of other factors must be considered The common types of steam sterilization cycles are gravity-displacement which removes air from the chamber by gravity displacement as steam-entering chamber exerts pressure on air and the pre-vacuum cycle which removes air by a vacuum pump while steam is simultaneously injected into the chamber

1

Background

Sterilization means the use of physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores Bacterial endospores are the most resistant of all living organisms because of their capability to withstand destructive agentsAlthough the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute when all parameters of the sterilization process have been metinstrumentssupplies and equipment are thought to be sterile

Sterilization falls into the following three categories1 High temperaturepressure sterilizationEg steam autoclave2 Chemical sterilization Eg Ethylene Oxide(EtO)3 Radiation sterilization Eg Gamma Electron Beam X-Ray

Using microbiological monitor is the only way to ensure that sterilization has been achieved Although thermally sensitive tapes and bag markers indicate exposure to sterilization conditions they do not verify that sterilization has been achieved Results of studies of the effectiveness of dental office sterilization have been variable with 2 to 20 failure rates in monitored sterilization attempts The majority of sterilization failures have been found to be due to human error rather than equipmentrsquos failureFrom the above three categories of sterilization High temperaturepressure sterilization which is performed by steam autoclave is the only sterilization technique that is going to be discussed throughout the end of this projectSteam autoclave is the oldest safest and the most cost effective method of sterilization inthe medical equipment industry It is an instrument used for sterilization of surgically used equipment by using steam form of distilled water

Problem statement

It is a statement form of a devicersquos problem Whenever a certain device fails to work it must be repaired to be reused For its correction or maintenance there should be proper problem statements concerning the devicersquos failure For instance in steam autoclave there may be many problems that make it non-functional Examples of these problems are briefly shown in this project under the topic of troubleshooting in chapter four

2

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

AbstractThe intention of this project is to have deep understanding of special biomedical equipment called steam autoclave It is an instrument used to sterilize microbiological life which exists on surgical equipment Every company producing this device has its own manual for installation maintenance and operation of the device Without reading this manual one cannot simply make the power ON since the device is too harmful and it has complex electric circuit which may cause shock if not properly operated The thing that motivates us to do this project on steam autoclave is due to such electric shock and contamination caused by the operatorrsquos error Therefore it is aimed at minimizing this and other problems concerning the device

Acknowledgement

We would like to thank our instructor AtoWondimu Fanta for his unexplainable moral support and encouragement towards this project We also show our gratitude to our friends and all who supported in one way or the other for the completion of this project In addition we would like to thank jimma university for providing full internet access for us to complete this project Finally we want to say thanks for God who made all this possible

ii

Table of contents

1 Chapter one pageIntroductionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip1Back groundhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip2Problemrsquos statementhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip2Objectiveshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip3TheMain topics of maintenance methodologyhelliphelliphellip4

2 chapter two Operational principles of steam autoclavehelliphelliphelliphelliphelliphellip7Technical specificationshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip7Sterilizing processhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip8Controlling partshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip9Methods of using steam autoclave helliphelliphelliphelliphelliphelliphelliphelliphellip9Schematic diagramhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip10Accessorieshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip11

3 Chapter threeInstallation of steam autoclavehelliphelliphellip11Items for autoclavinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip12Loading an autoclavehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip12Unloading an autoclavehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip13Quality controlhelliphelliphelliphelliphelliphelliphelliphelliphelliphellip14

General procedureshelliphelliphelliphelliphelliphelliphelliphellip154 Chapter four

Maintenance and troubleshootinghelliphelliphelliphelliphelliphelliphellip16Corrective maintenancehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16General preventive maintenancehelliphelliphelliphelliphelliphelliphelliphellip17

iii

Troubleshootinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip19

5 Chapter five

Result and conclusionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

Recommendationhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Appendices helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Lists of figures

1 figure1 schematic diagram of autoclave

2 figure2 maintenance cycle

lists of tables

1 table 1 autoclaversquos capacity

2 table 2 troubleshooting

3 table 3appendices

iv

CHAPTER ONE

Introduction

The machine described in this project is a steam autoclave sterilizer that has beenspecially designed to sterilize most of the materials and instruments used in dental surgeries doctorssurgeries and hospitals in generalThis project contains general information pertaining to autoclave operation and is to be used as a general referenceWhen performing autoclave operations all procedures must be performed in accordance withthe specifications provided by the customer and in accordance with federal provincial andmunicipal safety legislation and company procedures safety rules and regulationsThe operating cycles can be monitored by means of the pressure gauge warning lights and by theposition of the controlsAn autoclave is a specialized piece of equipment designed to deliver heat under pressure to a chamber with a goal of decontaminating or sterilizing the contents of the chamber Decontamination is the reduction of contamination to level where it is no longer a hazard to people or environment while sterilization is the total destruction of microorganisms presentThis is achieved because heat damages the cellrsquos essential structures including the cytoplasmic membrane rendering the cell no longer viable This will only occurs if the material is heated to the specific temperature for a given period of time These parameters will vary depending upon the nature of the microorganisms present and the characteristics of the load itselfTo facilitate this transfer of heat moisture is often added but this does not guarantee success A number of other factors must be considered The common types of steam sterilization cycles are gravity-displacement which removes air from the chamber by gravity displacement as steam-entering chamber exerts pressure on air and the pre-vacuum cycle which removes air by a vacuum pump while steam is simultaneously injected into the chamber

1

Background

Sterilization means the use of physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores Bacterial endospores are the most resistant of all living organisms because of their capability to withstand destructive agentsAlthough the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute when all parameters of the sterilization process have been metinstrumentssupplies and equipment are thought to be sterile

Sterilization falls into the following three categories1 High temperaturepressure sterilizationEg steam autoclave2 Chemical sterilization Eg Ethylene Oxide(EtO)3 Radiation sterilization Eg Gamma Electron Beam X-Ray

Using microbiological monitor is the only way to ensure that sterilization has been achieved Although thermally sensitive tapes and bag markers indicate exposure to sterilization conditions they do not verify that sterilization has been achieved Results of studies of the effectiveness of dental office sterilization have been variable with 2 to 20 failure rates in monitored sterilization attempts The majority of sterilization failures have been found to be due to human error rather than equipmentrsquos failureFrom the above three categories of sterilization High temperaturepressure sterilization which is performed by steam autoclave is the only sterilization technique that is going to be discussed throughout the end of this projectSteam autoclave is the oldest safest and the most cost effective method of sterilization inthe medical equipment industry It is an instrument used for sterilization of surgically used equipment by using steam form of distilled water

Problem statement

It is a statement form of a devicersquos problem Whenever a certain device fails to work it must be repaired to be reused For its correction or maintenance there should be proper problem statements concerning the devicersquos failure For instance in steam autoclave there may be many problems that make it non-functional Examples of these problems are briefly shown in this project under the topic of troubleshooting in chapter four

2

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Table of contents

1 Chapter one pageIntroductionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip1Back groundhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip2Problemrsquos statementhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip2Objectiveshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip3TheMain topics of maintenance methodologyhelliphelliphellip4

2 chapter two Operational principles of steam autoclavehelliphelliphelliphelliphelliphellip7Technical specificationshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip7Sterilizing processhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip8Controlling partshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip9Methods of using steam autoclave helliphelliphelliphelliphelliphelliphelliphelliphellip9Schematic diagramhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip10Accessorieshelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip11

3 Chapter threeInstallation of steam autoclavehelliphelliphellip11Items for autoclavinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip12Loading an autoclavehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip12Unloading an autoclavehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip13Quality controlhelliphelliphelliphelliphelliphelliphelliphelliphelliphellip14

General procedureshelliphelliphelliphelliphelliphelliphelliphellip154 Chapter four

Maintenance and troubleshootinghelliphelliphelliphelliphelliphelliphellip16Corrective maintenancehelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip16General preventive maintenancehelliphelliphelliphelliphelliphelliphelliphellip17

iii

Troubleshootinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip19

5 Chapter five

Result and conclusionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

Recommendationhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Appendices helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Lists of figures

1 figure1 schematic diagram of autoclave

2 figure2 maintenance cycle

lists of tables

1 table 1 autoclaversquos capacity

2 table 2 troubleshooting

3 table 3appendices

iv

CHAPTER ONE

Introduction

The machine described in this project is a steam autoclave sterilizer that has beenspecially designed to sterilize most of the materials and instruments used in dental surgeries doctorssurgeries and hospitals in generalThis project contains general information pertaining to autoclave operation and is to be used as a general referenceWhen performing autoclave operations all procedures must be performed in accordance withthe specifications provided by the customer and in accordance with federal provincial andmunicipal safety legislation and company procedures safety rules and regulationsThe operating cycles can be monitored by means of the pressure gauge warning lights and by theposition of the controlsAn autoclave is a specialized piece of equipment designed to deliver heat under pressure to a chamber with a goal of decontaminating or sterilizing the contents of the chamber Decontamination is the reduction of contamination to level where it is no longer a hazard to people or environment while sterilization is the total destruction of microorganisms presentThis is achieved because heat damages the cellrsquos essential structures including the cytoplasmic membrane rendering the cell no longer viable This will only occurs if the material is heated to the specific temperature for a given period of time These parameters will vary depending upon the nature of the microorganisms present and the characteristics of the load itselfTo facilitate this transfer of heat moisture is often added but this does not guarantee success A number of other factors must be considered The common types of steam sterilization cycles are gravity-displacement which removes air from the chamber by gravity displacement as steam-entering chamber exerts pressure on air and the pre-vacuum cycle which removes air by a vacuum pump while steam is simultaneously injected into the chamber

1

Background

Sterilization means the use of physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores Bacterial endospores are the most resistant of all living organisms because of their capability to withstand destructive agentsAlthough the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute when all parameters of the sterilization process have been metinstrumentssupplies and equipment are thought to be sterile

Sterilization falls into the following three categories1 High temperaturepressure sterilizationEg steam autoclave2 Chemical sterilization Eg Ethylene Oxide(EtO)3 Radiation sterilization Eg Gamma Electron Beam X-Ray

Using microbiological monitor is the only way to ensure that sterilization has been achieved Although thermally sensitive tapes and bag markers indicate exposure to sterilization conditions they do not verify that sterilization has been achieved Results of studies of the effectiveness of dental office sterilization have been variable with 2 to 20 failure rates in monitored sterilization attempts The majority of sterilization failures have been found to be due to human error rather than equipmentrsquos failureFrom the above three categories of sterilization High temperaturepressure sterilization which is performed by steam autoclave is the only sterilization technique that is going to be discussed throughout the end of this projectSteam autoclave is the oldest safest and the most cost effective method of sterilization inthe medical equipment industry It is an instrument used for sterilization of surgically used equipment by using steam form of distilled water

Problem statement

It is a statement form of a devicersquos problem Whenever a certain device fails to work it must be repaired to be reused For its correction or maintenance there should be proper problem statements concerning the devicersquos failure For instance in steam autoclave there may be many problems that make it non-functional Examples of these problems are briefly shown in this project under the topic of troubleshooting in chapter four

2

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Troubleshootinghelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip19

5 Chapter five

Result and conclusionhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

Recommendationhelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip20

References helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Appendices helliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphelliphellip21

Lists of figures

1 figure1 schematic diagram of autoclave

2 figure2 maintenance cycle

lists of tables

1 table 1 autoclaversquos capacity

2 table 2 troubleshooting

3 table 3appendices

iv

CHAPTER ONE

Introduction

The machine described in this project is a steam autoclave sterilizer that has beenspecially designed to sterilize most of the materials and instruments used in dental surgeries doctorssurgeries and hospitals in generalThis project contains general information pertaining to autoclave operation and is to be used as a general referenceWhen performing autoclave operations all procedures must be performed in accordance withthe specifications provided by the customer and in accordance with federal provincial andmunicipal safety legislation and company procedures safety rules and regulationsThe operating cycles can be monitored by means of the pressure gauge warning lights and by theposition of the controlsAn autoclave is a specialized piece of equipment designed to deliver heat under pressure to a chamber with a goal of decontaminating or sterilizing the contents of the chamber Decontamination is the reduction of contamination to level where it is no longer a hazard to people or environment while sterilization is the total destruction of microorganisms presentThis is achieved because heat damages the cellrsquos essential structures including the cytoplasmic membrane rendering the cell no longer viable This will only occurs if the material is heated to the specific temperature for a given period of time These parameters will vary depending upon the nature of the microorganisms present and the characteristics of the load itselfTo facilitate this transfer of heat moisture is often added but this does not guarantee success A number of other factors must be considered The common types of steam sterilization cycles are gravity-displacement which removes air from the chamber by gravity displacement as steam-entering chamber exerts pressure on air and the pre-vacuum cycle which removes air by a vacuum pump while steam is simultaneously injected into the chamber

1

Background

Sterilization means the use of physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores Bacterial endospores are the most resistant of all living organisms because of their capability to withstand destructive agentsAlthough the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute when all parameters of the sterilization process have been metinstrumentssupplies and equipment are thought to be sterile

Sterilization falls into the following three categories1 High temperaturepressure sterilizationEg steam autoclave2 Chemical sterilization Eg Ethylene Oxide(EtO)3 Radiation sterilization Eg Gamma Electron Beam X-Ray

Using microbiological monitor is the only way to ensure that sterilization has been achieved Although thermally sensitive tapes and bag markers indicate exposure to sterilization conditions they do not verify that sterilization has been achieved Results of studies of the effectiveness of dental office sterilization have been variable with 2 to 20 failure rates in monitored sterilization attempts The majority of sterilization failures have been found to be due to human error rather than equipmentrsquos failureFrom the above three categories of sterilization High temperaturepressure sterilization which is performed by steam autoclave is the only sterilization technique that is going to be discussed throughout the end of this projectSteam autoclave is the oldest safest and the most cost effective method of sterilization inthe medical equipment industry It is an instrument used for sterilization of surgically used equipment by using steam form of distilled water

Problem statement

It is a statement form of a devicersquos problem Whenever a certain device fails to work it must be repaired to be reused For its correction or maintenance there should be proper problem statements concerning the devicersquos failure For instance in steam autoclave there may be many problems that make it non-functional Examples of these problems are briefly shown in this project under the topic of troubleshooting in chapter four

2

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

CHAPTER ONE

Introduction

The machine described in this project is a steam autoclave sterilizer that has beenspecially designed to sterilize most of the materials and instruments used in dental surgeries doctorssurgeries and hospitals in generalThis project contains general information pertaining to autoclave operation and is to be used as a general referenceWhen performing autoclave operations all procedures must be performed in accordance withthe specifications provided by the customer and in accordance with federal provincial andmunicipal safety legislation and company procedures safety rules and regulationsThe operating cycles can be monitored by means of the pressure gauge warning lights and by theposition of the controlsAn autoclave is a specialized piece of equipment designed to deliver heat under pressure to a chamber with a goal of decontaminating or sterilizing the contents of the chamber Decontamination is the reduction of contamination to level where it is no longer a hazard to people or environment while sterilization is the total destruction of microorganisms presentThis is achieved because heat damages the cellrsquos essential structures including the cytoplasmic membrane rendering the cell no longer viable This will only occurs if the material is heated to the specific temperature for a given period of time These parameters will vary depending upon the nature of the microorganisms present and the characteristics of the load itselfTo facilitate this transfer of heat moisture is often added but this does not guarantee success A number of other factors must be considered The common types of steam sterilization cycles are gravity-displacement which removes air from the chamber by gravity displacement as steam-entering chamber exerts pressure on air and the pre-vacuum cycle which removes air by a vacuum pump while steam is simultaneously injected into the chamber

1

Background

Sterilization means the use of physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores Bacterial endospores are the most resistant of all living organisms because of their capability to withstand destructive agentsAlthough the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute when all parameters of the sterilization process have been metinstrumentssupplies and equipment are thought to be sterile

Sterilization falls into the following three categories1 High temperaturepressure sterilizationEg steam autoclave2 Chemical sterilization Eg Ethylene Oxide(EtO)3 Radiation sterilization Eg Gamma Electron Beam X-Ray

Using microbiological monitor is the only way to ensure that sterilization has been achieved Although thermally sensitive tapes and bag markers indicate exposure to sterilization conditions they do not verify that sterilization has been achieved Results of studies of the effectiveness of dental office sterilization have been variable with 2 to 20 failure rates in monitored sterilization attempts The majority of sterilization failures have been found to be due to human error rather than equipmentrsquos failureFrom the above three categories of sterilization High temperaturepressure sterilization which is performed by steam autoclave is the only sterilization technique that is going to be discussed throughout the end of this projectSteam autoclave is the oldest safest and the most cost effective method of sterilization inthe medical equipment industry It is an instrument used for sterilization of surgically used equipment by using steam form of distilled water

Problem statement

It is a statement form of a devicersquos problem Whenever a certain device fails to work it must be repaired to be reused For its correction or maintenance there should be proper problem statements concerning the devicersquos failure For instance in steam autoclave there may be many problems that make it non-functional Examples of these problems are briefly shown in this project under the topic of troubleshooting in chapter four

2

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Background

Sterilization means the use of physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores Bacterial endospores are the most resistant of all living organisms because of their capability to withstand destructive agentsAlthough the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute when all parameters of the sterilization process have been metinstrumentssupplies and equipment are thought to be sterile

Sterilization falls into the following three categories1 High temperaturepressure sterilizationEg steam autoclave2 Chemical sterilization Eg Ethylene Oxide(EtO)3 Radiation sterilization Eg Gamma Electron Beam X-Ray

Using microbiological monitor is the only way to ensure that sterilization has been achieved Although thermally sensitive tapes and bag markers indicate exposure to sterilization conditions they do not verify that sterilization has been achieved Results of studies of the effectiveness of dental office sterilization have been variable with 2 to 20 failure rates in monitored sterilization attempts The majority of sterilization failures have been found to be due to human error rather than equipmentrsquos failureFrom the above three categories of sterilization High temperaturepressure sterilization which is performed by steam autoclave is the only sterilization technique that is going to be discussed throughout the end of this projectSteam autoclave is the oldest safest and the most cost effective method of sterilization inthe medical equipment industry It is an instrument used for sterilization of surgically used equipment by using steam form of distilled water

Problem statement

It is a statement form of a devicersquos problem Whenever a certain device fails to work it must be repaired to be reused For its correction or maintenance there should be proper problem statements concerning the devicersquos failure For instance in steam autoclave there may be many problems that make it non-functional Examples of these problems are briefly shown in this project under the topic of troubleshooting in chapter four

2

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Objectives

General objectives the general objectives of this project is to let students to outstandingly understand what maintenance is how it is done when it should be done and what procedures are needed to do Besides it is also used to understand installing operating troubleshooting and maintaining general medical instruments These instruments differ in a way how to operate maintain install and etc Therefore every equipment has its own operational and maintenance manual So by looking through that manual one can achieve the intended performance or action of equipment

Specific objectivesspecifically this project briefly explains special medical equipment steam autoclave It is an instrument used for sterilization of surgical equipment to kill out all microbial life These text clearly talks about the equipmentrsquos operational principles installation purpose building blocks troubleshooting and maintenance Afterreading this project paper one can confidentially install troubleshoot operate and brilliantly maintain every types of steam autoclave used in hospitals

The basic topics of maintenance methodology

3

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

1 maintenance activities

This methodology refers to the action taken by technicians for maintaining an instrument The maintenance activity should be done by experienced technician Even if the availability of qualified technicians to accomplish maintenance and repair is readily available the tasks of the maintenance man are extremely difficult for the ever increasing usage of modern equipment some of the modern day equipment are often too complex too costly inappropriate and difficult to maintain in developing society The main definitions and types are briefly explained in chapter four of this project

2 Faults

Faults are the failure that one equipment exhibits It is the state of abnormality of the equipment Such failures may be caused by the operator or by the equipment itself Unless faults are corrected properly by the qualified technicians it will leads to the automatic expiration of the equipment To diagnosis this problem maintenance procedures should be taken In an autoclave there may be many faults which are caused by different problems such as The timer fails to operate The pressure gauge remainsat a standstill even during thesterilizing cycle Water remains in the chamber The machine fails to pressurizeduring the cycle The pressure increases veryslowly and etc

3 Reparability

Before disassembling certain equipment for maintenance one should identify whether it is repairable or not After its reparability is identified the technician can simply apply the maintenance to repair the equipment Reparability is a capacity of equipment to be maintained

4 Elements of maintenance methodology

There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipmentThe purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project

5 Nuances of preventivebreak down and reparability centered maintenanceThe time and way of performing preventive maintenance and repairing an instrument differs Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure For instance if the pressure gauge of steam

4

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

autoclave fails to work it must be repaired to return back to its former normal functionality Therefore the reparability of an instrument is extremely essential51 Preventivebreak down maintenance

Preventive maintenance is a type of maintenance where equipment is maintained before break down occurs This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment For random failure patterns which amount to 80 of the failure patterns condition monitoring proves to be effective52 Reparability centered maintenanceReliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context As a discipline it enables machinery stakeholders to monitor assess predict and generally understand the working of their physical assets This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery and write a Failure Mode Effects and Criticality Analysis (FMECA) The second part of the analysis is to apply the RCM logic which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA Once the logic is complete for all elements in the FMECA the resulting list of maintenance is packaged so that the periodicities of the tasks are rationalized to be called up in work packages it is important not to destroy the applicability of maintenance in this phase Lastly RCM is kept live throughout the in-service life of machinery where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained

6 Maintenance planning scheduling and organizationEvery maintenance activities should be planned scheduled and organized before its performance regardless of its difficulty But there may be unforeseen situations when equipment fails to work suddenly To correct such equipment there may not be enough time to plan so we may be enforced to maintain without plan But the probability for maintenance to be done without plan is very low

7 Reliability maintainability and availabilityEvery medical devices used in hospitals should always be reliable and maintainable

5

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipmentrsquos ability to be maintained Besides a medical device should also be available It means the equipment should be found at every hospital or other health centers

8 Spares provisioningIt is the act of providing spare parts of a medical device Every medical equipment posses their own building blocks from which it has been made These blocks should be complete to achieve the desired performance of equipment The absence of single part may cause non-functionality of the device For instance in steam autoclave the absence of knocks causes the steam to be uncontrollable

9 Networking and maintainability databaseThis networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely

10Reconditioning process

It is the act of checking the correct performance of equipment This process is very crucial for the safety of the equipment Unless reconditioning process carried out some devices may be non-functional

11 Computerized maintenance management system for medical equipment

The appropriate program is required to control the cure cycle of the autoclave Each cycle has a designated rise in temperature and pressure a precise cure period and a specific decrease in temperature and pressure Such processes are commonly termed the up ramp the cure cycle and the down rampThe operation of the autoclave requires the operator to select the controller or computer program specified in the work order for each cure cycle Any initial operation of the autoclave under a new computer program must be carefully monitored to ensure the program is within autoclave parameters and accurate in meeting operational requirements Only authorized personnel may set or make changes to the autoclave program

6

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

CHAPTER TWO

Operational principles

Application

Steam autoclave is used mostly for surgical instruments This method is not well suited for heat sensitive materials and instruments

Many surgical instruments are not designed to withstand prolonged heat and moisture of the steam sterilization process This leads to alternative sterilization categories chemical sterilization and radiation sterilization which allow heat and moisture sensitive materials to be sterilized

Steam by itself is not sufficient for sterilization and pressure that is greater than atmospheric is needed to increase the temperature of steam for thermal destruction of microbial life Steam for a specified time at required temperature must penetrate every fiber and reach every surface of items to be sterilized When steam enters the sterilization chamber under pressure

bull It condenses upon contact with cold items

This condensation frees heat simultaneously heating and wetting all items in the load thus providing heat and moisture

Any living thing will be killed when exposed to saturated steam at 120degC (250deg F) longer than 15 minutes As temperature is increased time may be decreased A minimum temperature-time relationship must be maintained throughout all portions of load to obtain effective sterilization At the end of the cycle re-evaporation of water condensate must effectively dry contents of the load to maintain sterility

1 technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need for functionality practical use and safetyThis autoclave has functional characteristics that make it unique ie

- Main switch to power the machine- 60 minute cycle program- Five minutes final drying phase- Switch to select the 121deg or 134deg cycle- Fully visible water filling from the top- Built in drying cycle with evaporation system- Continuous venting of the air in the chamber to encourage the maximum steam

saturation- Approved safety valves to prevent over-pressures

7

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

- Safety valve to protect the heating element- Safety thermostat to monitor the drying operation- 121deg - 134deg operating pressure switches- Chamber in seamless press-molded 1810 STAINLESS STEEL- 7 liter chamber capacity able to hold up to 3 trays- Condensation radiator to drain off the water at the end of the cycle- Used water can- Filling with the 250 cc dispenser2 Arranging the steam autoclave to sterilizing process

21 Standard sterilizingBefore being sterilized the instruments must be cleaned to remove blood residues incrustationsforeign bodies etc These impurities can damage the items being sterilized the autoclave componentsand prevent the sterilizing process from being correctly carried outThese instruments must be made of NON-ferrous material since they could damage the otherinstruments or the autoclave itselfTo achieve perfect sterilizing it is therefore important to proceed in the following way1 Rinse and brush the instruments under running water immediately after use to remove all deposits2 Place the instruments in the ultrasound machine with distilled water and detergent solution ifpossible3 Thoroughly rinse the instruments in demineralized water to prevent scaling stains4 Dry the instruments to eliminate all water residues which could lead to oxidation5 Wash rinse and dry the supplied trays and make sure that they are perfectly clean6 To ensure that packaged instruments are perfectly dried we recommend use of support art M9050supplied as an optional7 If loose instruments must be sterilized it is advisable to cover the trays with a paper or fabricnapkin to prevent direct contact with the tray surface do not place the instruments straight on to thetrays8 Scissors and forceps should be slightly opened Mirrors and containers should be placed upsidedown for the sterilizing process9 It is advisable to keep the instruments separated from each other to achieve a better sterilizingaction Overloading will impair the sterilizing process10 If packaged instruments must be sterilized on the trays place the packets with their transparent sidedownwards and do not overlap The packets should not be too large Drying will be difficult if theiredges overlap11 The machine can operate with a maximum 3 Kg load22Sterilizing hand-pieces1 Carefully read the hand-piece operation manual with particular attention to the part about sterilizing2 Wrap the hand-piece in the special sterilizing cloth3 Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricating oil frompolluting the pipes of the autoclave4 Proceed with a short cycle 121degC sterilizing program

8

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

5 Remember to immediately remove the hand-piece from the autoclave at the end of the sterilizingprocess6 It is inadvisable to sterilize hand-pieces using the night cycleIt is essential to place a chemical indicator in the autoclave on each cycle to ensure that the sterilizingprocess has taken place correctly

3 Controlling parts- 1 ndashwarning light to indicate drying cycle in progress - 2 - 134degC cycle indicator light- 3 - 121degC cycle indicator light- 4 - display- 5 ndashcycle programmer timer- 6 ndashpressure gauge- 7 ndashmain switch- 8 ndashcycle startstop- 9 ndash chamber- 10 ndashdoor opening device- 11 ndashreset heat

4 Method of usea) Open the door by means of the deviceb) Turn on the main switchc) Arrange the instruments on the supplied Trays without overlapping the packets The maximum load allowed is 1 kgd) Fill the chamber with distilled water using the supplied dispenser which holds 250 cc when fulle) Shut the door using its handlef) Select the required sterilizing time using the timer This time can vary depending on the loadof instruments and the type of material g) Activate the selected sterilizing cycle with specified buttonsh) If very delicate materials are sterilized it is advisable to remove them as soon as the cycle ends or even during the dry phase after making sure that the pressure gauge setting is Oslashi) Each time that a cycle is carried out place an indicator (the TERMALOG or VAPOR LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing processj) When the display reaches Oslash sterilizing will have terminated The door can then be opened with caution always after having made sure that the pressure gauge is on the Oslash settingk) The machine switches off automatically at the end of the cycle and issues an acoustic signall) If the instruments are still wet after sterilizing proceed as follows to complete the dryingprocess-leave the door ajar-select the Dry cycle-set the required number of minutes for the drying phase

9

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

-now repeat the drying cycle which will stop automaticallym) Use the supplied tool and wear protective gloves when removing the material from the chambern) Keep about 50 cm away from the appliance when the door is opened as residue steam could escape from the upper side of the door and could scald the operatoro) Open the door with care using the device and an upward movement always after checkingthat the pressure gauge setting is Oslash If no resistance is opposed the door will open easilywhen the device is moved from the right towards the leftp) If the door is not opened immediately after the sterilizing cycle ends condensed watery vapor could form on its surface and drip off on opening

5-Schematic diagram

Figure1 schematic diagram of steam autoclave6 Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches

CHAPTER THREE10

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Installation and sterilization process of steam autoclave

31 Capacityof steam autoclave that must be known by the operator before installation

Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 5060Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 21-11Gross weight Kg 20Operating temperatures celsius 121 to 132

Table1 steam autoclaversquos capacity

32 Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fits for that purpose The machine is sent packed on a wooden pallet Make sure that the packing has not been damaged andthat everything is in a perfect condition Handle the box by means of its handles and place it on asurface in the immediate vicinity of the place in which the machine is to be positioned (the weight ofthe model is given in chap 2 in the technical specifications)Remove the machine from its wrapping by pulling it out of the box vertically using 2 hooks (availableon the market) inserted into the two holes at the sides of the casing Remove the polystyrene filler ballsfrom around the machine Make sure that none of the parts has been damaged and that the machine iscomplete with all the accessories indicated in the consignment note Immediately contact our reseller ifdiscrepancies are discoveredAll the packing materials must be kept for guarantee purposes Machines returned without their originalpacking will not be acceptedInstall the autoclave in a well-ventilated place well away from sinks heat sources grinders and fromall other machines that create vibrations andor dustPlace the autoclave delicately on to a perfectly flat surface Take care to leave a space of about 5-10 cmall around the machine to allow for aerationAutoclave must be installed in a well-lighted place equipped with an electrical system that complieswith the current standards in forceRemember that cannot be built into other furniture as it is filled with water from the topFit the electric plug into a socket with the capacity of at least 10 amperes and equipped with an earth connection Make sure that the mains voltage ratingcorresponds to the value indicated on the label at the rear of the machine (230 Volts) It must only be filled with distilled waterto ensure that the electrical and air-operated devicesoperate efficiently and are long lastingCarry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR LINEEXTENDER)

11

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Keep the receipt which should be attached to the installation form and sent off along with the warranty-Never connect the plug of the machine to a reductionDo not install the machine in places at altitudes of more than 1200 mabove sea levelIf this is the case contact the manufacturer for a special version of themachineUse a bubble level to make sure that the surface on which the appliance isto be positioned is perfectly horizontal

33 items for autoclaving

Although autoclaving provides an economical way of sterilizing and decontaminating items not all material can be autoclaved Some materials are hazardous when they are autoclaved causing the generation of toxic noxious gas To identify what may or may not be autoclaved a general list of items has been included in this project

Items that CAN be autoclaved are- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines-Contaminated solid items such as petri dishes pipettes gloves paper towel-Items for sterilizations such as glassware media aqueous solutions equipment

Items that CAN NOT be autoclaved are- Materials containing solvents volatile chlorinated compounds (HCL bleach) or corrosive chemicals (such as phenol ether chloroform) etc- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics34 loading an autoclaveThis section will address the various steps to be undertaken when preparing and autoclaving the material to be decontaminated or sterilized The following factors will be discussed packaging (primary and secondary) identification requirements and the fundamentals of loading an autoclave to maximize steam penetration Each of these plays a critical role in ensuring a successful decontamination sterilization

Prior to Loading an Autoclave

Verification should be undertaken to ensure the autoclave has been functioning correctly and has been meeting the validation requirements This verification can be performed by

1) Reviewing the previous cycle log recordings

2) Examining the results of the daily verification records and

12

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

3) Speaking to the individual responsible for the autoclave

Packaging

As the success of the decontamination sterilization is dependent upon the penetration of heat how material is initially prepared will greatly affect the outcome Consideration must be given to the primary container (containing the contaminated waste) volume of liquid amounts of material and the secondary container (containing the primary container)The structural integrity of the container is an important consideration Not all containers withstand the demands placed on them during the autoclave process Desirable characteristics are heat resistance good thermal conductivity puncture proof and impervious to waterGood Choices

-borosilicate glass (Pyrex) has very low thermo expansion property and therefore resistant to breaking due to heating Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics-Stainless steel is a good heat conductor and thus facilitates sterilization

Poor Choices

Polystyrene (PS) Polyethylene (PE) and high density polyethylene (HDPE) do not resist heat wellIf there is a risk of material melting ensure they are placed in a secondary container which is resistant to heatTransporting Packaged Material to the Autoclave

When transporting material to be autoclaved use a cart with guard rails Ensure the use of a secondary container to collect any spillage should the cart be knocked or jarred during transport Use a direct but not heavily populated route Surface decontaminates the container prior to transport unless there is no risk of contamination This waste should be restricted to laboratory zones and not areas used by the general public Should this not be possible contact the EHSS for advice35 unloading an autoclave

The greatest risk of personal injury occurs during the process of unloading the autoclave Not only is the risk of burns or scalding significant but one may also be exposed to the vapor and gases generated by the inadvertent autoclaving of volatile chemicals Super-heated liquids also pose of risk of exploding if they are shaken or moved during the cooling process In addition glassware can break if the autoclave dooris opened too quickly and sufficient time is not provided for them to approach room temperatureConsequently extreme caution must occur during this final stage

36 Procedures to follow

13

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

1 Wear all necessary personal protective equipment2 The chamber pressure gauge of the autoclave should be zero before opening theautoclaversquos door3 Crack door slightly and stand back to allow steam to escape To minimize the risk of accidents caused by steam escape the person who opens the autoclave door should stand directly behind it4 Slowly open autoclave door Opening the autoclave door too quickly may resultIn a glassware breakage andor steam burns to the skin5 If boiling or bubbling is present wait until it subsides Assess the risk of super-heated liquids6 Over exposure of saline or water is not a critical factor (as it is with media) so these liquids may be allowed to cool (for 10 min) in the autoclave after cracking the door to release the steam This is also recommended for all other items7 Bring the autoclave trolley to the chamber8 Using heat resistant gloves carefully transfer the containers (pans) to the trolley Be careful not to jolt the containers as it could result in breakage9 Move the containers to a draft free area10 If not already cool wait 10 minutes prior to storing sterilized material or preparing autoclaved waste for disposal11 After every use it is advised to close the autoclave door but do not seal the door as this will shorten the life span of the rubber gaskets on the door12 Verify that the temperature sensitive tape has changed color or diagonal lines or the words ldquoautoclavedrdquo has appeared If no change appears on the tape the load is required to be re-autoclaved after placing new tape on the material Also verify the cycle log recorder to check the temperature and time attained If minimum time and temperature is not attained on the second cycle users should contact the person responsible for maintenance of the unit to initiate repairs Leave a note on the autoclave stating the problem and the it cannot be used until problem has be resolved13 The container that could be contaminated by a liquid splash (due to boil over) or by direct contact with contents of the waste bag (such as melted agar) should always be washed after each use

37 Quality control

A number of tools are available to assess the performance of the autoclave these include physical chemicaland biological indicators It is important to note that these indicators will only respond to time temperatureand moisture conditions and not to organic load

A Physical IndicatorsPressure and temperature recording devices Thermocouples can be placedinside the load to determine the temperature achieved in the bag itself

B Chemical Indicators

14

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

These indicators change color after being exposed to specific temperatures forexample heat sensitive tape Upon exposure to the given temperature the changewill occur it is not time related Therefore these indicators can only attest to thetemperature attained and not to exposure time and hence success of sterilizationC Biological indicatorsBiological indicators are used in the efficacy testing of the autoclave process toeffectively sterilize the contents being treated Bacillus stearothermophilusspores are used as they are the most resistant organism to steam autoclavingTo determine the effectiveness of the autoclave process the biological indicatormust be placed in a typical test load (solid or liquid) and exposed to the typicalcycle conditions This is the standard method of validating the effectiveness ofyour autoclave procedures Testing using a biological indicator must beundertaken daily unless otherwise authorized by EHSS

38 General Procedures

1 Read and follow the suppliers instructions2 Place B stearotheromophilus in centre of representative test load

3 Process load in normal fashion 4 a) Extract and incubate Bstearothermophilus sample as instructed bymanufacturerb Use another ampoule (same lot ) not autoclaved to act as a positive control 5 Check for color change at regular intervals during the incubation period(8 12 24 and 48 hours) If media is yellow and turbid the autoclave process has FAILED Immediately upon noting yellow coloration re-run all samples with new biological indicators 6 If failure continues to be noted either increases time of exposure or initiaterepairs to the autoclave Note the autoclave cannot be used again untilvalidations procedure indicates that autoclave is now adequately sterilizing the material 7 Record all results (Positive and Negative)

CHAPTER FOURMaintenance and troubleshootingTypes of maintenance

15

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

1 Run-to-failure maintenance

2 Preventive maintenance

3 Corrective maintenance

4 Improvement maintenance

5 Predictive maintenance

Even though all of these maintenance types are needed the two most commonly used types of maintenance to keep normal functioning of steam autoclave are preventive and corrective type

1 Corrective maintenance

Corrective maintenance is probably the most commonly used approach but it is easy to see its limitations When equipment fails it often leads to downtime in production In most cases this is costly business Also if the equipment needs to be replaced the cost of replacing it alone can be substantial It is also important to consider health safety and environment (HSE) issues related to malfunctioning equipment

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out to bring it back to working order Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance

Whenever certain biomedical equipment fails there must be enough technician power in hospital to correct the devicesrsquo failure Besides before failure there should also be preventive maintenance activities to prevent the equipment from failure The time and the way how certain medical instrument maintained differ

16

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Figure2 maintenance cycle

2 Generalpreventive maintenanceThe machine needs to be serviced in a particular way Users are therefore advised to comply with thebelow listed recommendations1048766Periodically check the condition of the electrical system with particular attention to the connectioncable1048766Periodically clean the door the seal and take particular care when cleaning the internal part of theboiler removing any scaling with the damp sponge (supplied with the machine) Correct cleaningof these parts of the machine will ensure that the sterilizing cycle takes place in the right way1048766If the machine is not to be used for a long period of time leave the door ajar and store it at a roomtemperature of gt8degC1048766Use a damp cloth to clean the casing of the machine Never ever use inflammable liquids for anyreason whatsoever

21 Daily routine maintenanceClear the door seal door window and generally clean the outer and inner surfaces of the machineClean the black silicone door seal the outer and inner edges and the part where the door rests on thesterilizing chamber and on which the seal must tightly fit Use the supplied sponge to do this The softpart of the sponge can be used to clean the seal while the rough part can be used to clean the edge of thechamberThis cleaning operation must be carried out regularly to remove all impurities that could lead to loss ofpressure inside the sterilizing chamberCheck the used water level and drain off the actual water into the sewer if necessary Then wash out thecan under running water

22 Weekly routine maintenance

17

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Clean the sterilizing chamber cleaning the trays and tray holders All traces of deposits must be removed from thebottom of the chamber Use the rough side of the supplied sponge for this operation attempting toeliminate any scaling that may have formedRinse everything with the same water used for the sterilizing process The trays and tray-holders mustalso be cleaned in this wayDrain the water and clean the tray

23 Monthly routine maintenanceLubricate the pins and locking mechanismsCheck the movement of the hinge and door locking pin Lubricate with Vaseline oilMake sure that the door is well regulated If it is excessively slack it must be adjusted by means of thesupplied wrench Turn the regulator at the rear of the door in a counterclockwise direction This will increase thepressure exercised by the sealAttempt to shut the door If some difficulty is encountered turn the regulator in a clockwise directionClean the entire autoclave cabinet with a slightly damp sponge including the door casing

24 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way the manufacturer advises users to carry out afunctional test to ensure that the temperature and pressure parameters of the machine comply with thestandards required for a correct sterilizing processThese tests must be conducted by personnel authorized by the manufacturer using calibrated andperiodically certified instruments The autoclave is able to accept probes for the sterilizing testsIt is advisable to have the appliance subjected to a Total Overhaul by After-sales Service staff at leastonce every 12 monthsThe operation of the safety valve installed at the rear of the machine must also be checked at least onceevery 12 months This is done by removing the protective casing and re-tightening the ring nut of thevalve by hand To prevent accidents this operation should obviously be carried out when the machineis cold and off

18

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

Troubleshooting

FAULTS CAUSES REMEDIESThe timer fails to operate -Power is not reaching the

board-board burnt-out

-replace the board-check t fuse on the board with the tester

The pressure gauge remains at a standstill even during the sterilizing cycle

-pressure gauge blocked or broken-no water in the chamber

-clean the tube or replace the pressure gauge-repeat the cycle

Water remains in the chamber

- The dry indicator light remains on and the water is not drained

- Replace or check the draining solenoid valve

The machine fails to pressurize during the cycle

- The heating element has burnt out- The wire has detached from the heating element- The safety thermostat has tripped

- Replace the heating element- Re-connect the wire- Press the reset alongside the control panel

Insufficient pressure for theselected cycle with indicatorlights permanently ON

- The bulb thermostat setting is incorrect- Not enough water in the boiler- Leaks from the door seal

- Slightly turn the thermostat in the clockwise direction- Comply with the instructions- Clean the seal and the chamber

The pressure increases verySlowly

- Chamber very dirty inside- Heating insufficient-Too much vapor issues from the breather union

- Clean the chamber as described in the maintenance section- Heating element rods loosened- Replace the complete breather union

The machine is not powered when the switch is turned ON

- Defective switch-No power is reaching the mains socket- Fuses in the machine burnt out

-Replace the switch and check the wires- Check the socket and electricity main- Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits

19

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

CHAPTER FIVEResults and Discussion

Steam sterilization inactivates microorganisms through the application of saturated steam under pressure It generally denotes heating in an autoclave employing saturated steam under a certain pressure to achieve the desired chamber temperature The process thermally damages the bacterial cell structure including the outer and cytoplasmic membrane and rendering the cell no longer viable The inactivation of bacterial cell vital mechanisms depends on the bacterial cell structure the temperature and duration of the heat exposure to which they are exposed In practical terms which means that it would take a longer time at lower temperatures to sterilize a population than at a higher temperature For example bacterial colony survival decreases with increasing duration of time of autoclaving at elevated temperature and automated pressure

Recommendations

Most operators do not know how to use steam autoclave and thus they become the victim of contamination Therefore based on this fact we want to write the following recommendationsAlways wear personal protective equipment in compliance with the directives that establish thecurrent accident-preventing provisionsDo not approach the machine with inflammable materialsDo not carry out repairs or maintenance work whilst the machine is operating or plugged into theelectricity main or when parts of it are hotOnly responsible adults may use the machine in places inaccessible to children Use the machine in a dry place sheltered from the rainPeriodically inspect the power cable to make sure that it is in a good conditionIf there are several persons in the place of work remember to keep at a safe distance from themachine to prevent accidental contact with hot parts Never ever operate the appliance unless the power cable is in a perfect condition and the structureundamagedIt is advisable to keep the door half-open when the appliance is not in use Do not move the machine when the tank is full of waterPay the utmost attention to those parts of the appliance that become hotduring operation and that still remain hot after it has been switched offKeep your face well away from the top part of the machine when thedoor is opened to prevent it from being scalded by steam Keep about 50cm away from the machine when opening the doorAs specified in the technical specifications these autoclaves operate at apressure that can reach 22 Bar at most Do not use the autoclave in animproper way and do not carry out maintenance operations while thesterilizing cycles are in progress Remember that the pressure is shownby the pressure gauge installed on the front of the machine itselfWait at least 20 minutes after the appliance has been switched off toallow the boiler to completely cool

20

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21

REFERENCES

- Laboratory Biosafety Guidelines Health Canada 3rd Edition-Draft Sept 20 2001- Laboratory Biosafety Manual 2nd Edition World Health Organization Geneva- ldquoUsing a Gravity Displacement Steam Autoclave in a Biomedical Laboratoryrdquo video produced by School of Public Health University of Minnesota under contract with National Institute of Allergy and Infectious Disease- CooneyTimmothy E Techniques For Steam Sterilizing Laboratory Waste AMSCOresearch and development- Autoclave Procedures Office of Radiation Chemical and Biological Safety Michigan StateUniversitySafety Net - Effective Use of Autoclaves University of California - Davis `EnvironmentalHealth and Safety University of CaliforniaBiological Safety Update UCSF Autoclave Quality Control Program University of California -San Francisco Environmental Health and SafetyMedical Waste Management Program University of California

APPENDICESHere are some abbreviations and symbols used in this textSymbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz

21