fi mms pro 011 maintenance techniques

8/2/2019 FI MMS PRO 011 Maintenance Techniques

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Revision: AMaintenance Management System

Date: 31-05-10

Maintenance TechniquesPage: 1 of 105

ZAKUM DEVELOPMENT COMPANY

Maintenance Techniques

FI-MMS-PRO-011

REV DATE DESCRIPTION PREPARED CHECKED APPROVED

A 31-05-10 Formatted to MMS Project Standard BB ID PS




Date: 31-05-10


Revision Control Sheet

Revision Date Description




Date: 31-05-10


TABLE OF CONTENTS

CHAPTER 1 ............................................................................................7 1. ABBREVIATIONS, DEFINITIONS and REFERENCES................................... 7

1.1 Abbreviations........................................................................................... 7 1.2 Definitions................................................................................................ 8 1.3 References............................................................................................ 10

CHAPTER 2 ..........................................................................................11 2. INTRODUCTION ........................................................................................... 11

2.1 Purpose ................................................................................................. 11 2.2

Scope .................................................................................................... 11

2.3 Objective ............................................................................................... 11 2.4 Introduction............................................................................................ 11

CHAPTER 3 ..........................................................................................12 3. UNINTERRUPTED POWER SUPPLY (UPS)................................................ 12

3.1 Routine Inspections............................................................................... 12 3.2 Performance Tests ................................................................................ 14 3.3 Thermographic Survey .......................................................................... 15

CHAPTER 4 ..........................................................................................16 4. SPLICING AND TERMINATING HIGH AND MEDIUM

VOLTAGE CABLES....................................................................................... 16 4.1 Procedure.............................................................................................. 16 CHAPTER 5 ..........................................................................................19

5. MAINTAINING AND CALIBRATING ELECTRICALPROTECTIVE DEVICES............................................................................... 19

5.1 Procedure.............................................................................................. 19 CHAPTER 6 ..........................................................................................21

6. ELECTRIC MOTOR....................................................................................... 21 6.1 Procedure.............................................................................................. 21

CHAPTER 7 ..........................................................................................23 7. CONTROL INSTRUMENT CALIBRATION.................................................... 23

7.1 Procedure.............................................................................................. 23 7.2 Differential Pressure Transmitter........................................................... 23 7.3 Control Unit ........................................................................................... 25 7.4 Current to Pressure (I/P) Transducer .................................................... 26

Appendix 7.1: Typical Flow Control Loop.............................................................. 28 CHAPTER 8 ..........................................................................................29

8. TESTING OF PROCESS ANALYSERS ........................................................ 29 8.1 Procedure.............................................................................................. 29 8.2 Routine Maintenance............................................................................. 29 8.3 Calibration ............................................................................................. 30

Appendix 8.1: Hydrogen Sulphide Analyser.......................................................... 32




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CHAPTER 9 ..........................................................................................33 9. MACHINERY ALIGNMENT ........................................................................... 33

9.1 Introduction............................................................................................ 33 9.2 Types of Alignment................................................................................ 33

Appendix 9.1: Alignment Graph Example ............................................................. 43 Appendix 9.2: Example of Alignment Record Reverse Indicator Method(Form No. 01/0221/04/F047.1) ............................................................................. 44

CHAPTER 10 ........................................................................................45 10. COMPRESSOR......................................................................................... 45

10.1 Procedure.............................................................................................. 45 10.2 Rotor Repair .......................................................................................... 46 10.3 Journal and Thrust Bearing ................................................................... 47 10.4 Thrust Bearing Adjustment .................................................................... 48 10.5 Labyrinth Seals...................................................................................... 48 10.6 Marking of Impellers .............................................................................. 48 10.7 Rotor Storage ........................................................................................ 49 10.8 Reporting............................................................................................... 49

Appendix 10.1: Troubleshooting Guide (1/4) ........................................................ 51 Appendix 10.1: Troubleshooting Guide (2/4) ........................................................ 52 Appendix 10.1: Troubleshooting Guide (3/4) ........................................................ 53 Appendix 10.1: Troubleshooting Guide (4/4) ........................................................ 54

CHAPTER 11 ........................................................................................55 11. PRESSURE VESSELS.............................................................................. 55

11.1 Procedure.............................................................................................. 55 11.2 Fired Heaters......................................................................................... 58 11.3 Roles and Responsibilities .................................................................... 59

CHAPTER 12 ........................................................................................61 12. VIBRATION MONITORING AND ANALYSIS ............................................ 61

12.1 Terms .................................................................................................... 61 12.2 Procedure.............................................................................................. 62

Appendix 12.1: Vibration Frequencies and Likely Causes.................................... 65 Appendix 12.2: Machinery Vibration severity Chart Classification ........................ 66 Appendix 12.3: Vibration Severity Chart ............................................................... 67 Appendix 12.4: Vibration Severity Chart ............................................................... 68 Appendix 12.5: Vibration Severity Chart ............................................................... 69 Appendix 12.6: Vibration Severity Chart ............................................................... 70




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CHAPTER 13 ........................................................................................71 13. LUBRICATION MANAGEMENT ................................................................ 71

13.1 Procedure.............................................................................................. 71 13.2 Roles and Responsibilities .................................................................... 71 13.3 Storage and Handling of Lubricants ...................................................... 72 13.4 Procedure.............................................................................................. 74 13.5 Roles and Responsibilities .................................................................... 74

Appendix 13.1: Example of Lube Oil Consumption Chart..................................... 75 Appendix 13.2: Weekly Lubrication Check Sheet(Form No. 01/0221/04/F0411.1) ........................................................................... 76 Appendix 13.3: Oil Analysis Report Form (Form No. 01/0221/04/F0411.2).......... 77 Appendix 13.4: Request for Lube Oil Analysis Form

(Form No.01/0221/04/F0411.3) ............................................................................ 78 CHAPTER 14 ........................................................................................79

14. THERMOGRAPHIC (INFRA RED) INSPECTION...................................... 79 14.1 Introduction............................................................................................ 79 14.2 Scheduling of Thermographic Inspections............................................. 80 14.3 Analysis of Findings............................................................................... 80 14.4 Safety .................................................................................................... 80 14.5 Roles and Responsibilities .................................................................... 81

CHAPTER 15 ........................................................................................82 15. MACHINERY BALANCING........................................................................ 82

15.1 Terms .................................................................................................... 82 15.2 Procedure.............................................................................................. 83 15.3 Roles and Responsibilities .................................................................... 87

CHAPTER 16 ........................................................................................88 16. PRESSURE SAFETY VALVES ................................................................. 88

16.1 Terms .................................................................................................... 88 16.2 Procedure.............................................................................................. 90 16.3 PSV Testing .......................................................................................... 92 16.4 Testing Frequency................................................................................. 93 16.5 Inspection/Testing Schedule ................................................................. 94 16.6 Line PSVs.............................................................................................. 94 16.7 Records ................................................................................................. 95 16.8 Roles and Responsibilities .................................................................... 95

Appendix 16.1: Typical Relief Valve Testing Schedule......................................... 97 Appendix 16.2: Relief Valve (Flanged Connections)............................................. 98 Appendix 16.3: Relief Valve (Screwed Connections)............................................ 99 Appendix 16.4: Relief Valve Inspection Record(Form No. 01/0221/04/F0414.1) ......................................................................... 100 Appendix 16.5: Relief Valve Inspection Report(Form No. 01/0221/04/F0414.2) ......................................................................... 101 Appendix 16.6: Relief Valve Inspection and Testing Record

(Form No. 01/0221/04/F0414.3) ......................................................................... 102




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CHAPTER 17 ......................................................................................103 17. SAFETY INTERLOCK FUNCTIONAL TEST............................................ 103

17.1 Introduction.......................................................................................... 103 17.2 Procedure............................................................................................ 103 17.3 Preventive Maintenance...................................................................... 104




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CHAPTER 1

1. ABBREVIATIONS, DEFINITIONS AND REFERENCES

1.1 Abbreviations

ADNOC Abu Dhabi National Oil Company

AIMS Asset Integrity Management System

BU-MS Business Unit Maintenance Support

CBM Condition Based MaintenanceCMS Corrosion Management System

EP Engineering & Projects

FI Facility Integrity

FIP Facility Integrity Plant

FIT Facility Integrity Technical

FLM First Line Maintenance

HSECES Health Safety & Environment Critical Equipment & SystemsHSEMS Health Safety & Environment Management System

IMS Inspection Management System

LEMS Lifting Equipment Management System

MMS Maintenance Management System

PEMS Pressure Equipment Management System

PIMS Pipeline Integrity Management System

PSV Pressure Safety Valve

RBI Risk Based Inspection

RCM Reliability Centred Maintenance

RTF Run To Failure

SIL Safety Integrity Level

UPS Uninterrupted Power Supply

ZADCO Zakum Development Company




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1.2 Definitions

Asset (physical) A formally accountable item.

Availability The ability to be in a state to perform as required, under givenconditions, at a given instant or over a given time interval.

Compliance Test A test used to show whether or not a characteristic or aproperty of an item complies with the stated requirements.

Condition BasedMaintenance

Preventative maintenance which include a combination ofcondition monitoring and/or inspection and/or testing, analysis

and then carry out some active maintenance action.

CorrectiveMaintenance

Maintenance carried out after fault recognition and intendedto put an item into a state in which it can perform a requiredfunction.

Criticality The numerical index of the severity of a failure or a fault.

Failure The termination of the ability of an item to perform a requiredfunction.

Inspection The examination for conformity by measuring, observing,testing or gauging the relevant characteristics of an item.

Item Any part, component, device, subsystem, functional unit,equipment or system that can be individually described andconsidered.

Maintainability The ability of an item under given conditions of use, to beretained in, or restored to, a state in which it can perform arequired function, when maintenance is performed under givenconditions and using stated procedures and resources.

Maintenance The combination of all technical, administrative and managerialaction during the life cycle of an item intended to retain it in,or restore it to, a state in which it can perform the requiredfunction.

MaintenanceManagement

All activities of the management that determine themaintenance objectives, strategies and responsibilities andimplementation of them by such means as planning, controland the improvement of maintenance activities and economics.




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MaintenanceStrategy

The management method used in order to achieve themaintenance objectives.

On LineMaintenance

Maintenance carried out on the item whilst it is operating andwithout impact on its performance.

PlannedPreventativeMaintenance

Maintenance carried out at predetermined intervals oraccording to prescribe criteria and intended to reduce theprobability of failure or the degradation of the functioningof an item.

Policy A definite course of action.

Reliability The ability of an item to perform a required function under givenconditions for a given time interval.

Strategy A plan or method for obtaining specific goals or results.

Time BasedMaintenance

Maintenance carried out in accordance with an establishedtime schedule or established number of units of use.




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1.3 References

ADNOC-COPV6-01 Code of practice on identification and integrity assurance ofHSE critical equipment and systems

AIMS/POMS/001 Plant Operating Management System

BS EN 13306 Maintenance Terminology

ISO14224:2006 Petroleum, Petrochemical and Natural Gas Industries – Collection and Exchange of Reliability and MaintenanceData for Equipment

ZADCO/AIMS/001 Asset Integrity Management System

FI-MMS-GEN-001 Generic Maintenance Strategy




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CHAPTER 2

2. INTRODUCTION

2.1 Purpose

The purpose of this document is to provide guide lines for carrying out maintenanceactivities by the Mechanical, Electrical and Instrumentation departments through outall ZADCO sites.

2.2 Scope

The scope of this procedure discusses basic methods for carrying out maintenanceat ZADCO sites.

2.3 Objective

The object of this procedure is to promote a greater understanding to basicprinciples in maintenance functions and aims to complement the genericmaintenance strategy along with the specific manufactures operations andmaintenance manuals.

2.4 Introduction

All work performed by the maintenance department must be executed under thework order and Permit to work systems as per ZADCO policy.

Incorrect maintenance of equipment can have a considerable impact on Safety,Environment and Production.

The aim of this procedure is to highlight the methods to be used for various

maintenance functions through out all ZADCO sites. It does not replace themanufacturer’s operations and maintenance manuals for specific instructions andparameter settings.




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CHAPTER 3

3. UNINTERRUPTED POWER SUPPLY (UPS)

3.1 Routine Inspections

3.1.1 General

Prior to isolation and opening of cabinets, check the following:

Room or adjacent areas are clean

Meters are functioning correctly

Indicator lights are working

External cubicle panels are free from corrosion

Ventilation systems are functioning correctly (panels and room), providingsufficient dissipation of generated heat

Special tools, battery connector spanners, etc. if provided, are in the correctlocations

Before internal inspections and especially before changing components, fuses etc.switch the unit off and isolate from power supply sources. This also includesisolation from the connected battery. Inform the user prior to isolation.

After isolation and opening of cabinets, perform the following:

Vacuum clean dust, dirt and other surface contaminants from all componentsand internal parts of the cubicles

Check mounting and condition of components inside panel

Check for corrosion

Fuses are correctly fitted and that their micro switches are correctly set.

Note: Fuses shall only be replaced with fuses that have the same rupturingcharacteristics.

Before closing the cabinet doors ensure all extraneous items are removed:spanners, rags, test equipment, etc.




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On completion of the work close all cabinet doors, make sure all fit securely andtightly, re-energise and check that:

UPS is operational: indicator lamps, meter readings, etc., are indicatingnormal operating condition

Ventilation is functioning

No unusual sounds or smells are detectable

3.1.2 Battery Inspection

Check the following:

Electrolyte level and specific gravity. (In some cases it is sufficient to onlycheck a random cell from each unit as long as there is a method establishedfor varying the selection of cell to be measured)

Connections: condition (corrosion) and tightness

Interconnectors: condition (corrosion) and tightness

On completion of the checks apply a smear of petroleum jelly to terminals andconnections.

It is dangerous to have open flames or ‘sparking’ near the cells.

3.1.3 Rectifier and Invertors

Visually check the following, using a torch or hand lamp:

All connections, leads, contacts are secure and free as possible from theeffects of vibration

Printed circuit boards are secure and plugged in correctly

Resistors, for signs of cracked enamel and over heating

Capacitors, for signs of leakage and case breakage

Inductors/transformers, for signs of vibration or over heating

Signs of over heating or connection defects on semiconductors or integrated

circuits




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Check transformer insulation using a 500v megger for the primary and a 250vmegger for the secondary:

Between phases

Phase to earth

Clean, test and check the operational movement of all electrical relays includingprotective devices.

3.2 Performance Tests

UPS On load:

Connect oscilloscope and DVM to UPS output, compare reading to theinstalled output meter, adjust meter if necessary

Compare waveform to manufactures illustration and adjust if necessary

Switch of primary feed:

Monitor oscilloscope for switching transients, voltage level and wave form

purity. Make adjustments to the static switch if there is a variance to themanufacturer’s parameters

Monitor voltage and specific gravity of battery during discharge, primaryfeed should be reconnected when cell voltages reach the manufactureslower limit

Time the period from primary feed disconnection to reconnection andcompare with the manufacturer’s specification

Re-initialise the UPS invertors as per the manufacturer’s instructions, check

synchronisation indicator and time to synchronise

Connect the spectrum analyser to the UPS output. Calculate each harmonicamplitude.If these exceed the manufacturer’s specification implement thecorrective actions necessary for compliance




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3.3 Thermographic Survey

Thermographic inspection shall be performed Thermographic (Infra Red Inspection)to identify hot spots. These are indications of potential failures:

High resistance connections

Faulty components

Circuitry imbalance

Battery charging rates too high or faulty cells

Restricted ventilation

Identified problems shall be investigated and corrected before further damage orfailure is incurred.




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CHAPTER 4

4. SPLICING AND TERMINATING HIGH AND MEDIUM VOLTAGE CABLES

4.1 Procedure

4.1.1 Prerequisites

Persons performing the works associated with this practice shall be certified at thestandard required by ZADCO and be familiar with:

Obtaining a Permit

Lock-Out/Tag-Out procedures

Permit restrictions in the area

Electric shock treatment

Emergency Procedures

Prior to cutting, stripping, terminating, etc., permits shall be taken out and the cableisolated. For a new installation, measures shall be taken to ensure that the cable isand remains at earth potential during the time required for the work to be performed.

Personnel, tools, and materials shall be screened from adjacent energised electricalconductors, terminals, etc. For high voltage work the recommended free spacebetween an electrical source and the area of work shall be maintained at all times.

All exposed electrical connections in the working area shall be connected to earth.

The means of isolating adjacent electrical sources shall be determined prior to

commencement of work.

4.1.2 Terminating

The bending radius of cables to be installed shall not be less than themanufacturer’s recommended minimum specification.

All cables shall be correctly identified prior to cutting and termination. Identificationtags shall be fixed that agree with the approved standard drawing. Both ends of thecable shall have clear and precise identification.

Sufficient length shall be allowed for termination, before cutting the cable.




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Cable glands:

Cable gland sizing: the correct size and type of cable gland for each cableshall be used

Drilling the gland plate: Mark the gland plate for drilling and remove ifnecessary. Drill the gland plate to the required size of cable gland. Removeall burrs and rough edges from drill holes

Completion of gland installation: All glands shall be installed as per themanufacturer’s instructions. Care shall be taken to avoid any crossthreading, stripping of threads, cracked gland entries, etc.

The size of the conductor, type of cable lug, and crimp shall be verified to ensurecompatibility and compliance to manufacturer’s specifications. Failure to do so mayresult in poor mechanical and electrical integrity of the termination.

The crimp dies shall be checked for mechanical damage prior to starting. Damageto the conductors or cable lug will occur if faulty crimp dies are used. A test shall becompleted on a separate conductor (test example) to ensure the dies areacceptable.

During termination of the cable the following shall apply:

Ensure that the correct cable lug, type and size is suitable for the connection

Cables must be secured to prevent undue mechanical stress on glands,conductors, or other terminations

All conductors, including spares, shall be terminated. Spare conductors shallbe terminated for future use

When stripping insulation from conductors, wires or strands, care must betaken to avoid damage with nicks or cuts. If damage occurs during stripping,inform the supervisor and wait for further instructions before proceeding

Ensure that all lugs are securely crimped and all terminations are tight to givegood electrical continuity

Ensure that the correct number of terminal lugs are installed in the terminalfixture. If this is not followed, loose connections in the terminal will causefurther problems

Ensure that only one wire/cable core is fitted into the terminal lug. The

practice of installing more than one wire into a lug, shall not be permittedwithout authorisation from the supervisor




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Prior to energising, insulation checks shall be carried out, and loop checks made toensure correct connections.

If required, Thermographic Inspection shall be performed Thermographic (Infrared)Inspection) on high voltage terminations to identify hot spots. These are indicationsof high resistance connections and shall be rectified immediately.

All surplus material shall be removed and disposed of in the supplied receptacles.On completion of the work, the area shall be cleared of all debris resulting fromthe work.

4.1.3 Splicing

Splicing or joining of conductors shall be kept to a minimum in any one run.

Select jointing kit suitable for cables to be joined and the environment to be used in.

Prepare cables by removing insulation and if applicable cable armouring, so thatcables can be glanded with sufficient length for cores to be joined using straightthrough connectors. Dimensions shall be dependent upon the joint selected.

Ensure cables and joint box are clean and moisture free.

Gland cable ends (see Terminating) into lower joint box. For armoured cablesconnect an earth strap between the two cable armouring to provide earth continuity.

Join cable cores using compression straight through connectors, ensuring correctphase connections. Insulate connectors using insulation sleeving and spread cablecores to provide maximum clearance within the joint box.

Test combined cable for continuity and insulation values.

Prepare joint filling compound.

Remove vent plugs and inject joint filler through the fill plug(s) until filler is ejectedfrom the vents. Replace vent plugs and filler plugs.

Re-test combined cable for continuity and insulation values.

On completion, lay cable so that no mechanical forces are applied to the joint.




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CHAPTER 5

5. MAINTAINING AND CALIBRATING ELECTRICAL PROTECTIVE DEVICES

5.1 Procedure

5.1.1 Protective Devices (Mechanical Movements)

Prior to removing the unit from the panel, refer to the manufacturer’s instructionsfor the removal procedure and the status requirements of the protected device,i.e. shutdown, other operating mode, etc.

Remove the relay from its case and check, by visual inspection, that there are nobroken or cracked moulded parts or other signs of physical damage, and that allscrews are tight and the various parts are firmly secure.

Where possible, carefully operate the moving parts manually (do not use excessiveforce)to check that the movement is smooth and free without any obstructions andfunctions correctly i.e. contacts make/break, etc.

Check that the contacts are untarnished and in good condition. If cleaning isrequired, use a flexible burnishing tool. This consists of a flexible strip of metal withan etched roughened surface. The polishing action shall be done delicately so thatno scratches are left. Ensure all corroded material is removed.

Note: Knives, files or abrasive paper or cloth shall not be used as this may leavescratches which increase arcing and deterioration of the contacts. Abrasivepaper or cloth may also leave minute particles of insulating abrasive materialin the contacts and thus prevent closing.

Jewelled movements shall be inspected for cracks by examining their surfaces with

the point of a fine needle. For damaged items refer to the manufacturer’sinformation for further instructions.

Before replacing in the case, check that no debris or other extraneous material isincluded if there is, remove it carefully using a small soft brush. Vacuum cleanersor pressurised air jets shall not be used.

Auxiliary relays shall be checked at the same time as the associated protectivedevices are inspected. The relay should be checked for pickup and drop out values.Normally no adjustments should be required. If changes are required, refer to themanufacture’s set up instructions.




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5.1.2 Protective Devices (Solid State)

Prior to removing the unit from the panel, refer to the manufacturer’s instructionsfor the removal procedure and the status requirements of the protected device,i.e. shutdown, other operating mode, etc.

Remove the relay from the case and visually check the following:

All connections, leads, contacts are secure and free as possible from theeffects of vibration




Inductors/transformers, for signs of over heating

Signs of over heating or connections defect on semiconductors or integratedcircuits

Clean and check the operational movement of all electrical relays.

5.1.3 Calibration

Due to the number of calibration tests and adjustments possible, reference shall bemade to the manufacturer’s information for the particular instruction required.




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CHAPTER 6

6. ELECTRIC MOTOR

6.1 Procedure

6.1.1 Inspection of LV Motor Control Systems

Prior to isolation check the motor to ensure:

The cooling system is functioning correctly and that the motor casing is notoverheating

Vibration is within acceptable limits (Ref: Chapter 4.10 Vibration Monitoringand Analysis)

Inform the user of the intended maintenance and verify the motor tag number iscorrect before isolation (Ref: Chapter 7.5 Work Permit System).

Inspect and clean the motor casing (frame) and guards. Check paint work fordamage or corrosion and report the condition (satisfactory or requires painting).

Note: Severe corrosion may indicate internal deterioration requiring the removal ofthe motor from service for complete internal inspection.

Open the motor terminal box:

Discharge the motor power supply cables to earth

Check the cable gland(s) for security and tightness

Check connections for corrosion or signs of tracking. Clean as necessary,

tighten and then apply a smear of grease

Inspect all cable insulations for heat marks, deterioration and identificationtags

Check terminal box gasket for damage, renew if necessary

Grease cover securing bolts, nuts or screws.

Test motor anti-condensation heaters and circuits for correct operation.




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Inspect and clean local control switch, emergency push button, glands andterminations.

Measure and record motor winding insulation resistance. Compare measurementswith historical measurements. Indications of deterioration shall be reported to thesupervisor before further actions are taken.

Inspect and clean motor earthing connections, measure and record earthingresistance value.

Check motor hold down bolts and coupling bolts for tightness and security.

Bearings shall be lubricated only when scheduled. Do not over-lubricate. Excessivegrease creates heat due to churning resulting in damage to the bearings(Ref: Chapter 4.11 Lubrication Management).

Motor Control Centre (MCC) inspection:

Check cable connections for condition and tightness

Inspect insulation for overheating

Inspect fuse holders for overheating

Open main contactor, clean pole faces and coil. Check for free operation

Check and clean arcing contacts and shields (if applicable). Contactsrequiring dressing shall be done with a fine file, emery cloth shall not be used

Perform functional tests to prove correct operation of remote, local and emergencypush buttons.

Check all indicator lamps for operation.

Test run motor and record voltage, current and speed (rpm).




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CHAPTER 7

7. CONTROL INSTRUMENT CALIBRATION

7.1 Procedure

The following practices can be performed independently or as normally preferred,combined together as an inspection/calibration of the complete control circuit.

7.2 Differential Pressure Transmitter

Inform the user of the intended maintenance and ensure that the removal of thetransmitter from service shall not affect ongoing process operations.

Verify the tag number is correct before isolating the transmitter impulse lines fromthe process. For a differential pressure transmitter, open the equaliser valve toequalise the pressures across the cell unit before isolation.

Slowly vent both sides of the transmitter to atmosphere.

Inspect the external condition of the transmitter for damage and/or corrosion. Clean

thoroughly.

Check the transmitter’s nameplate for maximum differential pressure to be applied.Do not exceed this value.

Open the transmitter to gain access to zero and span adjustment screws and testterminals.

If applicable, check the condition and security of parts and connections, ensuring theunit is clean and free from moisture, dust, corrosion, etc.

Connect the ammeter across the test terminals and adjust the zero adjustmentscrew until the reading is 4mA. The adjuster may be fitted with end stops, do notforce as serious damage to the transmitter may occur.

Attach a variable pressure source, compatible with the pressure differential beingmeasured, to the positive pressure side of the transmitter. Close the equaliser valveand increase the pressure to the desired full calibration pressure and adjust thespan adjuster screw until the ammeter reading is 20mA. Again the adjuster may befitted with end stops, do not force as serious damage to the transmitter my occur.




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Release the pressure and open the equaliser valve. Check the ammeter readingand if necessary adjust the zero adjustment screw until the reading is 4mA.

Repeat the span adjustment sequence again and adjust the span adjuster screwuntil the ammeter reading is 20mA.

Repeat the process of zero adjustment and span adjustment until compromisedsettings of the respective adjustment screws give a zero value of 4mA and a fullcalibration pressure of 20mA.

Check linearity by setting in turn, the input pressure to 25%, 50% and 75% of fullcalibration pressure and check the ammeter for readings of 8mA, 12mA and 16mA

respectively. If the output meter readings indicate poor linearity across the workingrange adjust the linearity adjustment screw to make the necessary improvement.This may affect the zero and span output readings and so re-adjustments may benecessary.

Record final ammeter readings and respective pressures, for zero, span andlinearity. Unsatisfactory results shall require the transmitter to be disconnected andremoved to the workshop for further investigation.

Check that the door/lid seals are clean and free from damage prior to closing thedoor/lid.

On completion:

Pressure transmitter:

Close the positive pressure vent valve and ensure the other side of thepressure cell is open to atmosphere

Close the equaliser valve

Open the process impulse line valve slowly until fully open

Differential transmitter:

Close both vent valves

Open both process impulse line valves slowly until fully open

Close the equaliser valve

Inspect impulse lines for damage or leaks




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7.3 Control Unit

Inform the user of the intended maintenance and ensure that the removal of thecontroller from service shall not affect ongoing process operations. Care shall betaken where the controller is part of a cascaded control system or where thecontrolled variable has an influence on other process conditions.

Verify the tag number is correct before isolating the controller.

Cable connections to the controller case:

Check connections for corrosion or signs of tracking. Clean as necessary

and tighten

Inspect all cable insulations for heat marks, deterioration and identificationtags

Remove or withdraw the control unit from the case so that an internal inspectionis possible (Ref: Manufacturer’s Manual).Visually check the following:

The unit is clean and free from moisture, dust, corrosion, etc.

All connections, leads, contacts are secure and free from the effects of

vibration




Inductors/transformers, for signs of vibration or over heating

Signs of over heating or connection defects on semiconductors orintegrated circuits

Return the controller to the service position and reconnect the supply power.Set the controllers mode of operation switch (manual/auto) to manual.

Check the zero setting output by turning the set point indicator to zero % and adjustthe zero adjustment potentiometer until the controller’s meter indicates zero. (If thecontroller does not have a meter refer to the manufacture’s instructions for externalmeter points and meter specification requirements).




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Check the span/range setting output by turning the set point indicator to full scale %and adjust the span adjustment potentiometer until the controller’s meter indicates100% of scale reading.

To check the dynamic characteristics of the controller in the control loopi.e. proportional (P), integral (I) and derivative (D), refer to the manufacturer’sinstructions for best method of adjustment.

Return the controller fully into the case (operating position) and reset the controllersmode of operation switch (manual/auto) and the set point indicator to the originalpositions.

7.4 Current to Pressure (I/P) Transducer

Complete the control unit inspection and calibration prior to the I/P transducerinspection.

Inform the user of the intended maintenance and ensure that the operation of the I/Ptransducer during testing, shall not affect the process operation.

Verify the tag number is correct before commencing.

Check the instrument air supply pressure is approximately 20 psi, adjust the

regulator if required. Check the air filter, clean or drain as necessary. Check all joints and pipe work for air leaks.

Inspect the external condition of the I/P transducer for damage and/or corrosion.Clean thoroughly.

Open the transmitter to gain access to zero and span adjustment screws and testterminals.

If applicable, check the condition and security of parts and connections, ensuring theunit is clean and free from moisture, dust, corrosion, etc.

Connect a large scale 0 – 20 psi pressure gauge to the output.

Check the I/P transducer output action characteristic:

Direct: 3 – 15 psi equivalent to 0 – 100%

Reverse: 15 – 3 psi equivalent to 0 – 100%




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Switch the control unit to manual and the set point to zero. Check the I/P transduceroutput for either 3 or 15 psi according to action characteristic. Adjust the zeroadjustment screw accordingly.

Set the control unit set point to full output (100%). Check the I/P transducer outputfor either 15 or 3 psi according to action characteristic. Adjust the span adjustmentscrew accordingly.

Repeat the process of zero adjustment and span adjustment until compromisedsettings of the respective adjustment screws give desired zero and span outputpressures.

Disconnect the test pressure gauge and re-connect the feed line of the processcontrol item of equipment (damper, pressure control valve, flow control valve, etc.),to the I/P transducer output.

Check that the door/lid seals are clean and free from damage prior to closing thedoor/lid.

Check the action of the process item of equipment over the specified full operatingrange by adjusting the control unit set point from zero setting through to full output(100%). Check that the equipment’s movement is smooth and uniform. Refer tothe equipment’s manufacture’s instructions for the particular maintenance and

calibration procedures.




Date: 31-05-10


APPENDIX 7.1: TYPICAL FLOW CONTROL LOOP

Differential

PressureTransmitter

Flow

ControlValve

Set Point

Control Unit

(4 - 20 mA)

(4 - 20 mA)

(3 - 15 p.s.i.)

Current to Pressure

Transducer (I / P)




Date: 31-05-10


CHAPTER 8

8. TESTING OF PROCESS ANALYSERS

8.1 Procedure

The operation of the analyser is based on two principles:

Hydrogen sulphide creates a brown stain on the surface of lead acetate impregnatedpaper.

The rate of this stain formation determines the measure of hydrogen sulphideconcentration in the sample.

8.2 Routine Maintenance

Inform the user of the intended maintenance and ensure that the removal of theanalyser from service shall not affect ongoing process operations or safety systems.

Verify the tag number is correct before isolating the analyser sample line from theprocess.

If the sample line into the analyser or any part of the analyser is to be disconnectedadequate precautions shall be taken to avoid inhalation and that the area is wellventilated. Hydrogen sulphide is highly toxic, concentrations greater than 10ppmshall be avoided.

Inspect the external condition of the analyser for damage and/or corrosion. Cleanthoroughly.

Open the analyser hood to gain access to the internals, check the condition andsecurity of parts and connections, ensuring the unit is clean and free from moisture,

dust, corrosion, etc.

Remove the tape transport unit and check the quantity of unused sensing tape.Replace with a fresh roll if required or at expiry date of tape.

Check and ensure that the level of the Bubbler [5% acetic acid used to humidify andslightly acidify the sample before it makes contact with the sensing tape] is abovethe red line, add more if required. Care shall be taken not to spill or drip any of theacetic acid solution as it is very corrosive to aluminium.




Date: 31-05-10


Remove optical units (lamp, large lens tube and balance tube) and clean thoroughlyusing a lint free soft cloth. Replace and re-align, ensuring the lamp is in line with thecentre axis of the large lens tube and the light beam completely fills the samplechamber window, without shadow and with minimal overlap.

Check seals and grommets for damage or ageing, renew as required. If in doubtperform pressure checks.

Restore analyser to operational status and check the flow rate is at the indicatedsetting, adjust if necessary. (Correct analyser calibration is dependent on the flowrate of the sample.)

Operate the analyser for three/four complete cycles and check operation.

8.3 Calibration

Zero adjustment:

Connect the sample input line to a ‘zero gas’ source (process gas without anytrace of hydrogen sulphide)

Turn the function switch to maximum sensitivity (x5) and allow a minimum of15 minutes for the reading to stabilise

Connect a voltmeter to the test position and adjust the zero potentiometeruntil zero volts is indicated. Allow time for memory circuits to settle (normally2-3 cycles)

Final adjustment shall be made using the meter located on the front ofthe unit

Return function switch to original setting

Span adjustment:

Turn the function switch to the check position and allow a minimum of15 minutes for the reading to stabilise

The units meter reading should equal the check reading noted on themanufacturer’s calibration specification. If there is a variance connect a voltmeter to the test position and adjust the span until the required reading isobtained. Allow time for memory circuits to settle




Date: 31-05-10


Final adjustment shall be made using the meter located on the front of theunit

Return function switch to original setting

If after the above adjustments (zero and span) the operation is still not satisfactory(unstable, continuous high or low readings, drifting, etc.), refer to the manufacturer’sinstructions for full calibration procedure including mixing and using test gassamples.




Date: 31-05-10


APPENDIX 8.1: HYDROGEN SULPHIDE ANALYSER

Lamp

Large convexlens

Large lenstube

Mirror

Small concavelens

Balance tube

Reference photocell

Measuring photocell

Treated paper tape

Sample chamber

Trigger slide




Date: 31-05-10


CHAPTER 9

9. MACHINERY ALIGNMENT

9.1 Introduction

Correct alignment of machinery is essential for long and continuous machine life.A machine that is misaligned will fail during service with such problems as bearing,mechanical seal and coupling failure. The coupling is the most directly affectedcomponent. In extreme cases of failure as a result of misalignment total destructionof a machine can occur.

Rotating equipment items are usually connected by flexible couplings. The couplingtransmits torque from one shaft to the other, while at the same time compensatingfor a very small amount of misalignment and end movement (axial thrust or endfloat) of the shafts. A degree of flexibility is incorporated into a coupling whichallows for changes in temperature or piping stress during normal operation. Flexiblecouplings will not compensate for misalignment, and are not an excuse for poormaintenance practices.

In general the amount of misalignment allowable depends on several factors suchas coupling size, speed at which the machine operates, and the distance between

the shaft ends. Normally the maximum amount of running misalignmentis considered individually for each piece of rotating equipment.

Uneven settling of foundations, uneven thermal expansion of components, shaftdeflection, coupling clearance wear, uneven bearing wear and dimensional changesin structural and rotating members all contribute towards shaft misalignment.

To reduce the effect of operational misalignment it is essential to align the shaft asnearly true as possible upon installation, including any recommended allowances forthermal expansion. Furthermore, alignment should be checked and corrected everytime equipment is disassembled for repair, or when piping is removed or replaced.

9.2 Types of Alignment

9.2.1 Cold Ambient Alignment

Is the task that involves the alignment of rotating machinery while at standstill andambient temperature. In certain cases this positioning should allow for thermalgrowth and material deflections that will occur between ambient and stabilisedoperating temperatures.




Date: 31-05-10


9.2.2 Hot Shaft Alignment

Also known as operating shaft alignment or service alignment. This is a task thatinvolves the monitoring of the change in shaft alignment from cold or ambientconditions to stabilised operating temperatures.

9.2.3 Collinear Alignment

This is when two shaft ends rotate about the same straight line or axis, they areconsidered aligned (Ref. Figure 9.1).

C L C L

Figure 9.1: Collinear Aligned Shafts

9.2.4 Parallel Offset

This indicates the amount of parallel misalignment between the centre lines of thetwo adjacent shaft ends (Ref. Figure 9.2).

C LC LOffset

Figure 9.2: Parallel Offset




Date: 31-05-10


9.2.5 Angular Offset

Angular or Face offset is the amount of angular misalignment of the shaft ends (Ref.Figure 9.3).

C LC L

Angular Displacement

Figure 9.3: Angular Offset

9.2.6 Parallel / Angular Offset

This indicates a combination of the above whereby a condition of both Paralleland Angular Offset exists between the shaft ends. This condition of misalignmentis most often encountered and requires the correction of each condition in turn

(Ref. Figure 9.4).

C L

C L

Angular Offsett

Parallel Offset

Figure 9.4: Parallel/Angular Offset




Date: 31-05-10


9.2.7 Alignment Tolerances

Prior to the alignment operation a check should be made on the allowable alignmenttolerance for the machine to be aligned as well as any thermal allowances. Thisinformation should be available in the equipment’s data file, which should includeprevious alignment records.

Caution should be exercised in using alignment tolerances given by couplingmanufacturers. These are liberal figures, while perhaps they are true for thecoupling itself they may be excessive for the equipment to be aligned. Figure 9.5below shows an upper absolute misalignment limit, and a lower.

1 2 3 4 5 7 10 20 30 50 100

50

30

20

10

5

3

2

1

-7

C e n t r e l i n e O f f s e t ( M i l s )

Distance (Inches) Between Flexure Planes

M a x i m

u m P e r m i

s s i b l

e M i s a

l i g n m

e n t

K e e p

N e t M i

s a l i g

n m e n t B

e l o w T h

i s L i n

e

Figure 9.5: Misalignment Tolerances

9.2.8 Sag

Sag occurs when using long indicator clamps, where gravity pulls the weight ofthe clamps down. The amount of Sag should always be measured in suchcircumstances and compensated for during the alignment corrections, i.e. CorrectedReading = Reading – Sag.




Date: 31-05-10


9.2.9 Periphery and Face Alignment

Generally when machinery is to be aligned one of the machine’s components isconsidered to be the stationary unit, and the other unit is aligned to it. The unitconsidered to be stationary is determined by local conditions such as: piping,established centre lines and accessibility to the unit.

This method is the most traditional method used, however, it has certain limitationsas follows:

If used to align a machine where one or both shafts cannot be turned run-outerror may occur due to shaft or coupling eccentricity

On a sleeve bearing machine axial float error may occur

When used with jigs and posts two or three axis levelling is required for bothanti-friction and sleeve bearing machines

Has a lower geometric accuracy than reverse indicator method for spans exceedingcoupling or jig diameter.

Graphing the results is more complex than with the reverse indicator method

However, it is a preferred method when distance between the two adjacent shaftends is less than one half of the coupling diameter, (this assumes face readings aretaken near the outside diameter).

This method should therefore only be used in ZADCO facilities taking intoconsideration the above aspects. The following is an outline of the method tobe used:

Soft Foot – Prior to the commencement of alignment it may be necessary to checkfor a condition known as ‘Soft Foot’. This is sometimes found in machinery wherebyone foot is on a different plane to the other feet. In severe cases a ‘Soft Foot’ can

cause fracturing of the machine’s foot or pedestal. It is therefore important toeliminate this problem if it is found to exist.

On the machine to be aligned place a Dial Test Indicator (DTI) on one of themachine’s feet, and zero the DTI (Ref. Figure 9.6)

Loosen the holding down bolt so that it is free from the foot, record thereading on the DTI. If a measurement of 0.003"/0.076mm, or more, is foundthen the foot should be shimmed to the reading recorded

Check all other feet in the same way individually




Date: 31-05-10


DTI

Shim

Machine Foot

Machine

Base Plate

Holding Down

Bolt

Figure 9.6: Checking for Soft Foot

Using the Periphery and Face method of alignment requires correction of angularand parallel alignment to be carried out separately in both axis. The first to becorrected should be the angular misalignment in the vertical axis or plane. However,prior to this stage the distance between shaft ends should be checked (DBSE). Thiscan be done by using an inside micrometer. The DBSE should be in accordancewith the distance given on the equipment’s layout drawing, and within the tolerancesprovided by the coupling manufacturer.

If a cold alignment is being carried out any adjustment for thermal growth should beincluded. Some manufacturers give thermal rise/expansion for each foot support.If cold alignment figures are not provided then the amount of thermal growth

(cast iron and steel) may be estimated using the following formula:

Vertical Growth = (Oper. Temp. + Amb. Temp.) (6.0 x 10-6 in./in. – °F)(Ht. in.)2

Machinery operating at over 300°F should be hot aligned by being thermally cycledto the normal operating temperature.

Fix a DTI to the machine to be aligned (Ref. Figure 9.7), set the DTI to zero at thetop of the hub (12-o’clock). Rotate the hub through 180° (6-o’clock) and take thereading off the DTI. If the reading is a minus value this means that the hub facesare in at the bottom; if the reading is a plus value this means that the hub faces arein at the top.




Date: 31-05-10


Feeler GaugeGauge Block

or Bar Stock

Inside

Micrometer

Dial Test Indicator

Measurement

Point

0o

90o

180o

270oMachine to

be Aligned

Staionary

Machine

Figure 9.7: Checking for Angular Misalignment

Shim corrections should be carried out as follows:

(a) Minus Value Reading: Add shims to the value of the reading at the back foot,or by removing from the front foot.

or

(b) Plus Value Reading: Add shims to the value of the reading at the front foot, or byremoving from the back foot.

Once the angular misalignment has been corrected then the next to be alignedshould be the parallel misalignment, this is achieved by fixing a DTI on the peripheryor rim of the same coupling hub (Ref. Figure 9.8).

Measurement

Point

0o

90o

180o

270o

Dial Test Indicator

Machine to

be Aligned

Staionary

Machine

Figure 9.8: Checking for Parallel Misalignment

At either 90° (3-o’clock), or 270° (9-o’clock) set the DTI to zero and rotate through180° in the same direction as above (i.e. clockwise or anti-clockwise) and record thereading.




Date: 31-05-10


The misalignment can now be corrected by moving the machine by means ofaligning bolts situated alongside the machine’s foot, after loosening the holding-down bolts (Ref. Figure 9.9). The amount of movement should be equal to half (½)of the Total Indicator Reading (TIR), moving both the front and back feet equally inthe direction away from the plus reading.

Machine Foot

Holding-Down Bolt

Alignment Bolt

Shimming

Machine Base

DTI

DTI

Machine Feet Alignment Bolts

S h a f t A x i s

Figure 9.9: Adjusting for Parallel Misalignment

If the DTI reading is a plus value, when read off the hub, then the machine must bemoved away from the DTIs. If the reading is a minus value then the machine mustbe moved towards the DTIs. In order to avoid any confusion it is advisable to placethe DTIs on the feet the same side as the hub clocks.

9.2.10 Reverse Alignment

Before commencing the procedure check the following:

Check for ‘Soft Feet’, as described above

Check DBSE, as described above

Check for thermal rise/expansion, as described above




Date: 31-05-10


A line sketch of the equipment (Ref. Figure 9.10) to be aligned should be made andthe following measurements recorded:

Distance between DTI centre points (C)

Distance between DTI pointer on stationary machine and front foot on unit tobe aligned (F1)

Distance between same point and the back foot (F2)

Indicate Driver and Driven units

C

F1F2

Driver

(Unit to be aligned)Driven

(Stationary Unit)

Figure 9.10: Reverse Alignment Required Measurements

It is advisable to obtain approximate horizontal alignment before commencingvertical alignment.

Zero the DTIs at the top of the coupling hubs, marking the hubs with chalk, or inkmarker, and rotate both hubs through to 180°. Record readings from both clocks(Ref. Figure 9.11).

DRIVER DRIVEN

Bolt Hubs Together To Enable

Them To Be Turned Together

Figure 9.11: Clock Arrangement for Reverse Alignment




Date: 31-05-10


From the measurements gathered it is possible to either calculate by formula or bygraph the required shim corrections. The graphical method is the easiest methodto use.

When plotting an alignment graph it is always necessary to change the value symbolon the stationary unit, i.e. if the DTI reading is a minus value then it becomes a plusvalue on the graph, and vice versa. The machine to be aligned always remains thesame value when plotting the graph, i.e. a plus reading off the DTI remains plus onthe graph (Ref. Table 9.1).

DTI Readings Plotting Values

Example Stationary Aligned Stationary Aligned

1 - + + +

2 + - - -

3 - - + -

4 + + - +

Table 9.1: Alignment Value Readings

It must be remembered that the DTI readings are Total Indicator Readings and

should be halved when plotting.

When plotting the graph it is advisable to scale the graph as large as possible.Include on one side of the graph the measurements for C, F1, F2 and the DTIreadings. This will assist in historical record keeping, therefore final shimcorrections should also be recorded on the graph. It is also advisable to use a crosshatch rather than a dot when plotting as this is more accurate.




Date: 31-05-10


APPENDIX 9.1: ALIGNMENT GRAPH EXAMPLE

C = 8"

F1 = 12"

F2 = 24"

0 0

+0.122"

C

F1F2

Driver

(Unit to be aligned)

Driven

(Stationary Unit)

+0.046"+0.036" +0.076"+0.082"

+0.118"

0.320"

0.120"

0.059"

0.061"

Shim Adjustment:

Front Foot = +0.120"

Back Foot = +0.320"




Date: 31-05-10


APPENDIX 9.2: EXAMPLE OF ALIGNMENT RECORD REVERSE INDICATORMETHOD (Form No. 01/0221/04/F047.1)

REVERSE INDICATOR ALIGNMENT RECORD

Site: Eqpt. Tag No.:

Driver: Driven:

Coupling: Size:

DBSE:

Date:

00

Ambient Temp F Operating Temp Fo o

Expected Growth of Driver Leg mils: IB OB Driven coupling face to Driver Leg, in: IB OBIndicator Sag, mils TIR:

Mount indicators on the Driver and read the driven Hub:

OD Readings, TIR

at Driver Hub

OD Readings, TIR

at Driven Hub

NB: The vertical and horizontal sums of the readings should be equal.

Sum of Driver Readings: Vertical.................. Horizontal................

Sum of Driven Readings: Vertical................. Horizontal................

TIR (Corrected for sag), mils: Face................. OD...............

Remarks:

Data Taken By:...................................

Signature:...........................................

Shim required for IB Leg. mils............. (Actual used)..............

Shim required for OB Leg, mils............(Actual used)..............

SAFETY NOTE: Correct & Proper Isolation (i.e. electrical,

spectacle spade, etc.) Shall Be Carried Out.

NB: Accuracy required: +/- 0.005" (0.13mm)




Date: 31-05-10


CHAPTER 10

10. COMPRESSOR

10.1 Procedure

10.1.1 Failure Analysis Trouble Shooting

Centrifugal compressors very often do not have a standby unit available. Single, un-spared centrifugal compressors may support the entire operation of a process orplant. Timely recognition of compressor machinery problems is therefore important.Appendix A shows the most likely problems that may occur with centrifugalcompressors (and their Lube Oil Systems), however, this guide is not allencompassing. Certain aspects, such as vibration, bearings, couplings, etc.will require a deeper insight than the guide shown.

When investigating or troubleshooting a machines’ failure, depending on the specificproblem, the following may be taken into consideration:

Vibration patterns

Bearing temperatures

Oil condition (by analysis)

Process conditions (from Production Operators log book)

Inspection of internals (by dismantling or Boroscope)

Past history

In order to have a successful failure analysis programme it is essential to have

a good data collecting approach, data examination process and a well organisedreporting system. For this reason coded statements referring to Failure, Cause,Action should be used in the feedback information. In general, to perform a goodand concise failure analysis the following shall be required:

Designated person or team to perform failure analysis

Collect general data

Separate relevant observations from extraneous source/agency




Date: 31-05-10


Perform appropriate calculations

Correlate calculations and relevant observations

Establish most probable cause, with sequence of failure events

It is important that Equipment Failure Reports are easily understood. Reportsshould therefore be summarised as follows:

Situation Analysis – this is the symptom and the observations

Problem Definition – this is the diagnosis and the type of problem

Possible Solution – this could be short term solution, and may not be arecommended course of action

Preferred Solution – this is the recommended course of action

10.2 Rotor Repair

As centrifugal compressor rotor repair is a complex task, it has been traditional tohave this work carried out by the original equipment manufacturer (OEM), or an

outside workshop with rotor repair capabilities. However, if the rotor repair is carriedout by ZADCO personnel the following should be noted:

Remove the rotor according to the manufacturer’s instructions contained within theOperating and Maintenance Manual.

As the rotor assembly is a critical part of the machine, extreme precautions shouldbe taken when handling it. If a crane is used to remove the rotor assembly a chainblock should be attached to the crane hook, and the chain block be used to lift outthe assembly, and NOT the crane. (Ref. Figure 10.1). This ensures a smoother andmore accurate lift of the rotor.

When inspecting the rotor, look for rubs, wear or corrosion marks. If the rotor hasbeen severely damaged, the assembly should be reconditioned by returning it tothe OEM, an outside workshop with experience in the particular compressorrotor repair, or by the ZADCO workshop, if it has the appropriate skills, tools, etc.The reconditioned rotor should be balanced after being reconditioned.

The labyrinths should be inspected for wear, and parts replaced if excessive wear isnoted.

All parts should be carefully cleaned.




Date: 31-05-10


During reassembly particular care should be taken when fitting the casings andother components. The bolt tightening sequence, and torque figures, should befollowed, as given in the manufacturer’s manual.

Crane Jib

Chain Block

Figure 10.1: Use of Chain Block With Crane

10.3 Journal and Thrust Bearing

Proceed as described in the manufacturer’s instructions, contained within theOperating and Maintenance Manual, in order to gain access to both inboard andoutboard journal bearings and thrust bearing assemblies.

The bearings and housings should be inspected thoroughly. Each bearing or pad,if equipped with tilting pad bearings, should be checked for signs of wear and score

marks. The thrust bearing collar should be checked for signs of heat cracks.Any bearings or pads that are damaged to the extent that Babbitt has lifted orremoved completely should be replaced.

O-rings should be inspected for any defects such as: nicks, cracks, materialdeterioration, etc.

All other parts should be inspected for cleanliness and damage to threads, etc. andreplaced as necessary.

Care should be taken during reassembly to ensure that the parts remain in positionand are free from dirt and foreign matter.




Date: 31-05-10


If the thrust collar has to be removed or replaced then an hydraulic tool has to beused. On reassembly the thrust collar retaining nut should not be over tightenedas this may result in a bent shaft.

10.4 Thrust Bearing Adjustment

After reassembly and installation of the thrust bearing, the thrust bearing end playshould be checked and compared to manufacturer’s recommendations.

If the thrust bearing end play is less than the manufacturer’s recommendationsshims should be added in order to obtain the required end play. However, makecertain that the pads, where fitted, are not cocked or out of place.

If the required end play is excessive it is generally an indication that the thrustbearing is worn. Refer to the manufacturer’s Operations and Maintenance Manualfor the correct procedure to make adjustment to the thrust bearing clearance.If adjustment is not possible, replace the parts that are out of tolerance.

10.5 Labyrinth Seals

Removal and disassembly of labyrinth seals should be carried out as describedin the manufacturers instructions, contained within the Operating and Maintenance

Manual. The labyrinth feathers are extremely fragile, therefore great care shouldbe take to make sure that they are not damaged. They should retain a knife edgeappearance.

The running clearance should be checked between the seal and the rotor shaft.Excessive clearance will require the seals to be changed. The correct runningclearance will be contained within the Manufacturer’s Operating and MaintenanceManual.

O-rings should be inspected for any defects such as: nicks, cracks, materialdeterioration, etc.

Care should be taken during the seal reassembly to ensure that no dirt or foreignmaterial gets between the labyrinth feathers and the rotor.

10.6 Marking of Impellers

Stamping of numbers on impellers should never be allowed. A high speed pencilgrinder may be used in low stress areas. Burn marks from the use of a pencilgrinder should be avoided as they cause stress raisers, which have been knownto cause fatigue failures.




Date: 31-05-10


10.7 Rotor Storage

Spare rotor assemblies should ideally be stored vertically in a remote temperaturecontrolled storage building. If horizontal storage is opted for, the rotor should beplaced on substantial stands and turned 180° two to four times per year. The standsmust employ rollers rather than lead or Teflon® at the support points. Use ofTeflon® sheet material placed between the storage cradle and the rotor createsa risk of filling the microscopic pores of the shaft journal, and thus preventing theformation of an adequate oil film.

10.8 Reporting

Following an overhaul it is important to monitor the start up. This should be donewith the aid of a fixed base vibration monitoring system, or if this is not available,a portable vibration monitoring system to obtain baseline vibration data forcomparison with previous operating information.

Hot alignment readings can normally be taken a couple of hours after start up. Oncethe process has stabilised sufficiently, which can in some case be several days,the machines performance can be checked.

All of this information should be recorded in the equipment’s history data file.It should not be delayed until a convenient time after the overhaul.

The equipment’s overhaul report should include such detail as:

Basic Machine Data – This is a brief description of the machine(manufacturer, model number, number of stages and other physicalparameters, serial number, date purchased, date of last overhaul, and reasonfor current overhaul)

Performance, Vibration and Mechanical Health Data – This is a comparisonbetween pre--and post-overhaul levels. This data should include:

performance and vibration data for the train, including process flow, pressureand temperature, machine case, and eddy current probe vibration levels, oilsupply pressure and temperature, oil return temperature. Use of calibratedinstruments is mandatory

Spare Parts – This is a list of complete spare parts for the machine as well asspare parts actually used. The list should show manufacturers part numbersand ZADCO warehouse stock numbers

Critical Dimension Diagram – This is a diagram showing as-founddimensions, and should include manufacturers dimensions. This information

should include such detail as: total rotor float, thrust clearance, rotor positionwithin the total float, labyrinth clearances, radial bearing clearances, nozzlestand-off, coupling bluing check, and coupling advance




Date: 31-05-10


Rotor Run-out Diagram and Balance Report

Shaft Alignment Record – This should show desired readings based onanticipated thermal growth, readings prior to overhaul, readings afteroverhaul, actual measured thermal growth data

Photographs of the Overhaul

A Discussion of the Overhaul – This should refer to the appropriatephotographs throughout

Recommendations – This should include: future overhauls, reconditioning

worn but reusable parts

Shift Logs and Backup Data as Required




Date: 31-05-10


APPENDIX 10.1: TROUBLESHOOTING GUIDE (1/4)

Compressor Surges

Excessive Vibration Water In Lube Oil

Possible Causes

Possible Causes

Possible Remedies

Possible Remedies

Symptoms

# A B C D E F G #

# #A B C D E F G

D

C

B

A

E

F

G

TROUBLESHOOTING GUIDE - CENTRIFUGAL COMPRESSOR & LUBE SYSTEM

Low Lube Oil Pressure

Loss of Discharge Pressure Excessive Bearing Oil Drain Temp.

Units Do Not stay In Alignment

R o t o r / B e a r i n g S y s t e m

Excessive Bearing Clearance *Replace bearings

Wiped Bearings *Replace bearings*Determine & correct cause

1 13 1

2 7 2

Rough Rotor ShaftJournal Surface

*Stone or restore journals*Replace shaft

Bent Rotor Caused ByUneven Heating orCooling

*Turn rotor at low speed until vibrationstops, then gradually increase speedto operating speed.

*If vibration continues, shut down,determine & correct the cause.

4 48

55 9Operating In CriticalSpeed Range

*Operate at other than critical speed.

Build-Up of Deposits On Rotor *Clean up deposits from rotor.*Check balance.

6 10 6

Build-Up Of Deposits in Diffuser *Mechanically clean diffusers.

C o u p l i n g

Unbalanced Rotor *Inspect rotor for signs of rubbing.*Check rotor concentricity, cleanliness,loose parts.

7 73

88 11

Damaged Rotor *Replace or repair rotor.*Rebalance rotor.

99 12

3 39

Loose Rotor Parts *Repair or replace loose parts.

Shaft Misalignment *Check shaft alignment at operating

temperatures.

*Correct any misalignment.

Dry Gear Coupling *Lubricate coupling

Worn or Damaged Coupling *Replace coupling.

*Perform failure analysis.

Liquid Slugging *Locate & remove the source of liquid.

*Drain compressor casing of any

accumulated liquids.

Operating In Surge Region. *Reduce or increase speed until

vibration stops.

*Consult vibration analysis guide.

Insufficient Flow *Increase recycle flow through machine.

O p e r a t i n g C o n d i t i o n s

Change In System Resistance Due

to Obstructions or Improper Inlet or

Discharge Valve Positions.

*Check position of inlet/discharge

valves.

*Remove obstructions.

Compressor Not Up To Speed *Increase to required operating speed.

4

1010 15

11 11

12 126

13 137

14 1414

15 1516

16 161

17 172

5

18 181

N.B. The numbers in columns A to G indicate what to check first, or the possibility ranking.




Date: 31-05-10



Compressor Surges


Possible Causes

Possible Causes

Possible Remedies

Possible Remedies

Symptoms

# A B C D E F G #

# #A B C D E F G

D

C

B

A

E

F

G

TROUBLESHOOTING GUIDE - CENTRIFUGAL COMPRESSOR & LUBE SYSTEM (Cont.)




O p e r a t i n g C o n d i t i o n s

19 2 19

2222 4

L u b e O i l S y s t e m

23 231

2525

2424 2

3

217

Excessive Inlet Temperature *Correct cause of high inlet temperature.

Leak In Discharge Piping. *Repair leak.

Vibration. *Refer to "A" in symptom column.

Sympathetic Vibration. *Adjacent machinery can cause

vibration even when the unit is shut

down, or at certain speeds due to

foundation or piping resonance. A

detailed investigation is required in

order to take corrective measures.

Improperly Assembled Parts. *Shut down, dismantle, inspect, correct

A s s e m b l y

Loose Or Broken Bolting. *Check bolting at support assemblies.

*Check bed plate bolting.

*Tighten or replace.

*Analyse.

Piping Strain. *Inspect piping arrangements andproper installation of piping hangers,

springs, or expansion joints.

S u p p o r t S y s t e m

Warped Foundation or Bedplate. *Check for possible settling of the

foundation support.

*Correct footing as required.

*Check for uneven temperatures

surrounding the foundation casing.

Faulty Lube Oil Pressure Gauge or

Switch.*Calibrate or replace.

Oil Reservoir Low Level. *Add oil.

Clogged Oil Strainer/Filter. *Clean or replace oil strainer or filter

cartridges.

Relief Valve Improperly Set or

Stuck Open.*Recondition or replace.

Incorrect Pressure Control Valve

Setting on Operation.

*Check control valve for correct setting

and operation.

20 20

21

3 1

26 262

27 271

28 282

29 29

30 305

2

Faulty Temperature Gauge or

Switch.

*Calibrate or replace

31 31

32 32

8

9





Date: 31-05-10



Compressor Surges


Possible Causes

Possible Causes

Possible Remedies

Possible Remedies

Symptoms

# A B C D E F G #

# #A B C D E F G

D

C

B

A

E

F

G





34 5 34

3535 6

3636 7

33 334

Inadequate Cooling Water Supply *Increase cooling water supply to lube

oil cooler.

*Check for above design cooling water

inlet temperature.

Fouled Lube Oil Cooler. *Clean or replace lube oil cooler.

Operation at a Very Low Speed

Without The Auxiliary Oil Pump

Running (If Main L.O. Pump is

Shaft Driven).

*Increase speed or operate aux. lube

oil pump to increase oil pressure.

Bearing Lube Oil Orifices Missing

or Plugged.

*Check to see that lube oil orifices are

installed and are not obstructed.

*Refer to lube oil system schematic

diagram for orifice locations.

Oil Pump Suction Plugged. *Clear pump suction.

Leak in Oil Pump Suction Piping. *Tighten leaking connections.

*Replace gaskets.

Failure of Both Main & Auxiliary Oil

Pumps.

*Repair or replace pumps.

Oil Leakage. *Tighten flanged or threaded

conections.

*Replace defective gaskets or parts.

Clogged or Restricted Oil Cooler,

Oil Side.

*Clean or replace cooler.

Inadequate Flow of Lube Oil. *Refer to "D" in symptom column.

*If pressure is satisfactory, check for

restricted flow of lube oil to affected

bearings.

Water in Lube Oil *Refer to "G" in symptom column.

37 3711

38 383

39 394

40 406

41 4110

Poor Oil Condition/Gummy Deposits

on Bearings.

*Change oil.

*Inspect and clean lube oil strainer or

filter.

*Check and inspect bearings.*Check with oil supplier to ascertain

correct oil type being used.

42 42

43

1

3

4444 8



43




Date: 31-05-10



Compressor Surges


Possible Causes

Possible Causes

Possible Remedies

Possible Remedies

Symptoms

# A B C D E F G #

# #A B C D E F G

D

C

B

A

E

F

G




*When shutting down, stop cooling

water flow to oil cooler.

*Commission lube oil conditioning unit.

*Refer to lube oil management guide.

NOTE: Vibration may be transmitted

from the coupled machine. To localise

vibration, disconnect coupling and

operate driver alone. This should help

to indicate whether driver or driven

machine is causing vibration.

Condensation in Oil Reservoir. *During operation maintain a minimum

lube oil reservoir temperature of 120 F

to permit separation of entrained

water.

o46 462

Leak in Lube Oil Cooler Tube(s) or

Tube Sheet.

*Hydrostatically test the tubes and

repair as required.

*Replace zinc protector rods (if

installed) more frequently if leaks are

due to electrolytic action of cooling

water.

45 451







Date: 31-05-10


CHAPTER 11

11. PRESSURE VESSELS

11.1 Procedure

11.1.1 Pressure Vessels

The following shall be considered for each pressure vessel inspection and repair:

11.1.2 Safety Instructions

Check availability of safety instructions, documentation and maintenance records.

11.1.3 Personnel Safety (Ladders, Stairways, Platforms, Walkways)

Check visually ladders, stairways, platforms and walkways for corroded or brokenparts, cracks, tightness of bolts, wear of ladder rungs and stair treads, security ofhandrails and condition of flooring on platforms and walkways.

11.1.4 Supports

Check supports for corrosion, distortion and cracking, condition of fire proofingwhere applicable and condition of anchor bolts.

11.1.5 Protective Coating and Insulation

Check visually protective coating and insulation.

11.1.6 External Metal Surface

Check visually external metal surfaces. This inspection should be supplemented bypicking, scrapping and limited hammering to locate corroded areas. Wall thicknessmeasurements on corroded areas shall be performed.

11.1.7 Internal Metal Surface

Check visually all internal parts of the vessel for corrosion, erosion, hydrogenblistering, deformations, cracking and laminations.




Date: 31-05-10


11.1.8 Nozzles

Check nozzles for distortion, cracking and leak. Perform wall thicknessmeasurements if loss of thickness is expected.

11.1.9 Safety Devices

Reference should be made to the relevant chapters contained within this manual,and ZADCO Inspection Guide.

11.1.10 Thickness Measurement

Measure wall thickness at location of most deterioration.

11.1.11 Electrical Safety

Check grounding connection and for good electrical contact. Cable resistance mustbe checked at intervals. Reference should be made to the relevant section in theZADCO Inspection Guide.

11.1.12 Testing

Testing shall be performed after each important repair, and at regular intervalsduring the life of the installation.

11.1.13 Boilers

The following shall be considered for each boiler inspection and repair:

11.1.14 Running Inspection

The following checks shall be performed:

Personnel safety: check ladders, platforms, stairways for broken parts,securing means, handrails, etc.

Check external casing for hot spots (refractory breakdowns)

Connections, shorts, grounds, etc. Reference should be made to the relevantsection in the ZADCO Inspection Guide




Date: 31-05-10


11.1.15 External Inspection

In addition to the above the following shall be performed:

Check foundations, boiler supports, structural members for distortions,cracks, corrosion, etc.

Check furnace walls, access doors, peep-holes, latches

Check casing and piping for corrosion

Check safety valve seats. Reference should be made to the ZADCO

Inspection Guide, G6, Pressure Safety Devices Check-List

11.1.16 Internal Inspections

The following inspections should be carried out during a boiler shutdown:

Perform a preliminary inspection, before boiler cleaning, to determinelocations requiring a close inspection

Check visually pipes, pipe joints and refractory linings for leaks and

breakdowns

Perform internal inspection of: Drums, drum connections and internal partsand nozzles, water headers, super heater headers (erosion, steam cuttingand corrosion of inside surfaces), furnace and firesides, refractory lining(cracks, erosion, melting, etc.), baffles (displacement of fall-out)

Check overall status of auxiliary equipment

Check safety devices. Reference should be made to the relevant section inthe ZADCO Inspection Guide

11.1.17 Testing

The following tests should be carried out in relation to boilers:

Check for scale deposits

Popping pressure test for safety valves and operation test for other safetydevices

Thickness measurements on corroded/eroded areas




Date: 31-05-10


Electrical Megger test

Boiler pressure test

11.2 Fired Heaters

11.2.1 Running Inspection

General Aspect – Check general aspect of the heater to estimate theadequacy of maintenance, and to localise areas or parts requiring a closerinspection

Personnel Safety (Ladders, Stairways, Platforms, Walkways) – Check visuallyladders, stairways, platforms and walkways for corroded or broken parts,cracks, tightness of bolts, wear of ladder rungs and stair treads, security ofhandrails and condition of flooring on platforms and walkways

External Casing – Check external casing for hot spots showing location ofinsulation deterioration

Instrumentation and Safety Devices – Check condition and operation ofinstruments. Check safety valves. Reference should be made to the relevant

chapters contained within this manual, and ZADCO Inspection Guide

Electrical Safety – Check grounding connection and for good electricalcontact. Cable resistance must be checked at intervals. Reference shouldbe made to the relevant section in the ZADCO Inspection Guide

11.2.2 External and Internal Inspection

Explosion Doors – Check explosion doors for corrosion and operability(Opening with minimum resistance)

Foundations and Supports – Check foundations and structural supports forcracks, corrosion, distortion, etc.

Safety Valves – Check popping pressure of safety valves

Upon internal examination, the following shall be performed:

Refractory and Insulation – Check visually refractory and insulation forbreakdowns

Tube Supports – Check tube supports for cracks, oxidation and corrosion




Date: 31-05-10


Tubes – Check externally tubes for sagging or bowing, bulging, oxidation,scaling, cracking, splitting, external corrosion, external deposits, leakingwalls, etc.

Check visually inside of tubes, if removal is possible, for corrosion, thinning of tubeends, cutting or other cleaning damages, looseness of the tube roll and erosion.

If internal examination is not possible, measure thickness of accessible tubes andbundle by ultrasonic method.

11.2.3 Testing

The following tests should be performed, as applicable:

Analysis for scale deposits

Thickness measurements

Deformation measurements

Electrical Megger test

Pressure testing

11.3 Roles and Responsibilities

11.3.1 Site Maintenance Team Leader

Site Maintenance shall be responsible for the following:

Repair of pressure vessels, boilers and fired heaters. They shall carry out therepairs in accordance with recognised industry standards, and follow ZADCO

safety policies in doing so

Request inspection services from ENGQ on site when statutory inspections,repair inspections are scheduled on pressure vessels, boiler and fired heaters

In co-ordination with Production, Site Maintenance shall schedule theinspection and repair of pressure vessels, boilers and fired heaters

Site Maintenance will consult with ENGQ for technical advice relating torepair procedures, and painting, corrosion and engineering material selectionfor pressure vessels, boilers and fired heaters




Date: 31-05-10


11.3.2 Site Production Team Leader

Site Production shall be responsible for the following:

Ensure the safe isolation, draining and purging of pressure vessels, boilersand fired heaters prior to hand-over to maintenance

To co-operate with Site Maintenance in the inspection and maintenanceschedule of pressure vessels, boilers and fired heaters

Witnessing and approving pressure tests on vessels, boilers, and firedheaters

They shall be ultimately responsible for inspecting and approving repairs topressure vessels, boilers and fired heaters

11.3.3 FIP

FIP shall be responsible for the following:

Provide annual inspection schedule for statutory items

Provide inspection and quality control services for statutory inspections ofpressure vessels, boilers and fired heaters

Provide inspection and quality control services for repair work on pressurevessels, boilers and fired heaters. This shall include inspection report withrepair recommendations, and the standards to be followed

Provide inspection of repair work to pressure vessels, boilers and firedheaters to ensure that the repairs comply with the repair recommendations

Provide an annual inspection schedule for pressure vessels, boilers and fired

heaters

11.3.4 Business Unit Maintenance Support (BUMS)

BUMS shall be responsible for the following:

Provide any support required to Site Maintenance in the inspection and repairof pressure vessels, boilers and fired heaters




Date: 31-05-10


CHAPTER 12

12. VIBRATION MONITORING AND ANALYSIS

12.1 Terms

The following terms are used in this procedure

12.1.1 Frequency

The number of cycles completed by a periodic quantity in a unit time.

12.1.2 Amplitude

The maximum absolute value attained by the disturbance of a wave or any quantitythat varies periodically.

12.1.3 Spectrum

A spectrum is a calculated data display of frequency versus amplitude.

12.1.4 Measurement Point

A location on a machine where the pick-up or vibration sensor is placed to takea measurement.

12.1.5 Alarm Limits

Levels of amplitude that indicate a deteriorating condition on a machine.

12.1.6 Analysis Parameters

Provide data acquisition information and the ability to divide the frequency spectruminto selected frequency bands that can be measured and analysed separately.




Date: 31-05-10


12.2 Procedure

12.2.1 Introduction

Condition Monitoring requires a knowledge of many parameters: vibration, oilcondition, temperature and pressure hot spots, material thickness, corrosion rates,etc. Of these, vibration, temperature and pressure are the most commonly used.

To predict a machine’s condition in the future requires these parameters to bemeasured over a period of time so that suitable trend analyses can be performed.Measurements must therefore be both reliable and repeatable. Takingmeasurements on a regular basis must be practical, cost-effective, and safe. Only

on this basis can the measurements be used: first to establish meaningful alarmlevels and then to enhance the ability to estimate time to failure.

Damage does not occur all of the time, but takes place in episodes of the machinesrunning time and is related to specific types of operational situations. Rotatingequipment malfunctions often manifest themselves in vibration, or a change invibration patterns. Vibration analysis is therefore an important diagnostic tool forprocess equipment troubleshooting. The following are a number of ways thatvibration data can be obtained for detecting and identifying specific problems withrotating equipment:

Amplitude v Frequency

Amplitude v Time

Amplitude v Frequency v Time

Time Waveform

Vibration analysis is a two stage process whereby the necessary vibration datais obtained, and then evaluated in order to identify specific problems.

Prior to undertaking a vibration monitoring programme on an item of rotatingequipment, it is advisable to consider the machine and the circumstances which leadto a requirement for vibration analysis.

12.2.2 Vibration Monitoring/analysis Program

A strong predictive maintenance programme should include a vibrationmonitoring/analysis program that can incorporate new technologies as the programmatures. In order to achieve this, a vibration monitoring program is required to becreated in a host computer at each site. Measurements taken are down loaded intothe data base for analysis. Where it is warranted on major machinery, on linemonitoring should be employed.




Date: 31-05-10


The programme should require dedicated persons at each site to carry out datacollection, and administer the system. The persons should define the routes of datacollection and carry out according to the pre-defined frequency of data collection.

For security reasons only, it is advisable to store the collected data in a secondarydata base situated in Abu Dhabi. However, it should be fully understood that eachsite is responsible for its own programme.

12.2.3 Alarm Limits

Wherever possible alarm limits should be set according to the equipmentmanufacturers’ recommendations. In the event that manufacturers’ recommendations

are not available then limits should be set according to ISO 2372 and 3945.

Baseline ratio alarms should be incorporated into the program which tell that themachines’ condition should be evaluated in detail. In such cases more frequentmonitoring should be carried out, and plans made for spare parts and labourrequired for the impending work.

12.2.4 Data Collection

The technician shall follow a route, or set of routes. Each route should provide an

ordered list of machines and their associated measurement points for the technicianto follow when collecting data. The route should specify under which spectra andwaveforms are saved for each point.

Following the route order, the technician shall take measurements at each point withthe pick-up. Data such as ‘leaking oil on Machine A,’ should be keyed in while enroute. At the end of the route the technician shall download the data into the hostcomputer.

12.2.5 Analysing Data

On a data collection run hundreds of measurement points may be surveyed.However, only a few of these points may contain suspect data, or indications ofproblems arising. The software available should sense those pieces of data thatindicate problems in the making.

Any potential impending problems should be investigated further and additionalor more frequent data carried out.

BU-MS and FI should, when requested, assist in the analysis and troubleshootingof equipment problems. Appendix 12.1 may be used as a guide in the identification

of vibration causes.




Date: 31-05-10


12.2.6 Responsibilities

Site Maintenance (Mechanical) shall be responsible for carrying out the vibrationmonitoring program except for high speciality requirements.

Site Maintenance Team Leader shall ensure that the vibration monitoring programis carried out, and that dedicated technicians are assigned to the program. He shallensure that the program grows with technological advancement.

FIT shall assist Site Maintenance in the execution of the vibration monitoringprogram. This shall include assisting in the analysis of machinery problems, andadvising on technological advancement.

Technician shall carry out data acquisition by following the pre-defined routes at therequired frequency. He shall note any abnormal conditions with machinery, otherthan vibration, and note them in the data base. He shall report any abnormalconditions noted immediately to the appropriate supervisor.




Date: 31-05-10


APPENDIX 12.1: VIBRATION FREQUENCIES AND LIKELY CAUSES

Frequencyin TermsOf RPM

Most Likely Causes Other Possible Causes and Remarks

1 x RPM Unbalance 1) Eccentric journals, gears or pulleys.2) Misalignment or bent shaft – if high

axial vibration.3) Bad belts if RPM of belts.4) Resonance.5) Reciprocating forces.6) Electrical problems.

2 x RPM MechanicalLooseness

1) Misalignment if high axial vibration.2) Reciprocating forces.3) Resonance.4) Bad belts if 2 x RPM.

3 x RPM Misalignment Usually a combination of misalignmentand excessive axial clearances(Looseness).

Less than1 x RPM

Oil Whirl (Less than½ RPM)

1) Bad drive belts.2) Background vibration.

3) Sub-harmonic resonance.4) ‘Beat’ vibration.

Synchronous(AC LineFrequency)

Electrical Problems Common electrical problems includebroken rotor bars, eccentric rotor,unbalanced phases in poly-phasesystems, unequal air gap.

2 x Synch.Frequency

Torque Pulses Rare as a problem unless resonance isexcited.

Many TimesRPM

(HarmonicallyRelatedFreq.)

Bad GearsAerodynamic Forces

Hydraulic ForcesMechanicalLoosenessReciprocating Forces

Gear teeth times RPM of bad gear.Number of fan blades times RPM.

Number of impeller vanes times RPM.May occur at 2, 3, 4 and sometimeshigher harmonics if severe looseness.

HighFrequency(NotHarmonicallyRelated)

Bad Ant-FrictionBearings

1) Bearing vibration may be unsteady – amplitude and frequency.

2) Cavitations, re-circulation and flowturbulence cause random, highfrequency vibration.

3) Improper lubrication of journal bearings

(Friction excited vibration).4) Rubbing.




Date: 31-05-10


APPENDIX 12.2: MACHINERY VIBRATION SEVERITY CHARTCLASSIFICATION

Ranges of radial vibration severity

Quality Judgement

for seperate classes

of machines

Class I Class II Class III Class IV

K M G T

Range

0.28

0.45

0.71

1.12

1.8

2.8

4.5

7.1

11.2

18

28

45

71

cms velocity

in The Range 10-1000Hz

at the range limits

MM/S PK IN/SEC

0.28 0.011

0.45 0.018

0.71 0.028

1.12 0.044

1.8 0.071

2.8 0.11

4.5 0.18

7.1 0.28

11.2 0.44

18 0.71

28 1.1

45 1.8

0.4

0.63

1.0

1.58

2.54

3.95

6.36

10.0

15.8

25.4

39.5

63.6

A

B

C

D

A

B

C

D

A

B

C

D

A

B

C

D

MACHINE CLASSES

CLASS I Small Machines to 20HP (15kW).

CLASS II Medium Size machines 20 to 100 HP (kW).

CLASS III Large Machines 10-200 rev/sec, 400 HP and Larger, Mounted on Rigid Supports (300Kw).

CLASS IV Large Machines 10-200 rev/sec, 400 HP and Larger, Mounted on Flexible Supports (300Kw).

ACCEPTANCE CLASSES

A GOODB SATISFACTORY C UNSATISFACTORYD UNACCEPTABLE




Date: 31-05-10


APPENDIX 12.3: VIBRATION SEVERITY CHART

12.5 16 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400Hz/Sec

MACHINE CLASS I (K)

ISO 2372

[ G O O D ]

[ S A T I S F A

C T O R Y ]

[ U N S A T I S F A

C T O

R Y ]

[ U N A C C E P T A B L E ]

SPk

Disp

V E L O C I T Y ( e f f ) = 4 . 5 m m / s

V

1 . 8

0 . 7

100

80

63

50

40

31.5

25

20

16

12.5

10

8

6.3

5

4

3.15

2.5

2.0

1.6

1.25

1.0

100

um

60

50

40

30

25

20

15

10

8

6

5

4

2.5

2.0

1.5

1.0

0.8

0.6

0.5

0.4

0.3

0.25

P k D i s p

0.8

0.63

0.5

0.4

0.315

0.25

3.0

80

500 630 800 1000

15 20 25 30 40 50 60 80 100 150 200 250 300 400

1000800 1500 2000 2500 3000 4000 5000 6000 8000 10000 15 20Revs/Min

500 600 800 1000

25 30 40 50 60.103

Cycles/Sec

S

A v e

r a g e p o i n t o f d e t e c t i n g v i b r a t i o n b y a h u m a n 0 . 1 1




Date: 31-05-10



12.5 16 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400

Hz/Sec

MACHINE CLASS II (M)

ISO 2372

[ G O O D ]

[ S A T I S F A C T O

R Y ]

[ U N S A T I S F A C

T O R Y ]

[ U N A C C E P T A B L E ]

SPk

Disp

V E L O C I T Y ( e f f ) = 7 . 1 m

m / s

V

2 . 8

1 . 1

100

80

63

50

40

31.5

25

20

16

12.5

10

8

6.3

5

4

3.15

2.5

2.0

1.6

1.25

1.0

100

um

60

50

40

30

25

20

15

10

8

6

5

4

2.5

2.0

1.5

1.0

0.8

0.6

0.5

0.4

0.3

0.25

P k D

i s p

0.8

0.63

0.5

0.4

0.315

0.25

3.0

80

500 630 800 1000

15 20 25 30 40 50 60 80 100 150 200 250 300 400

1000800 1500 2000 2500 3000 4000 5000 6000 8000 10000 15 20Revs/Min

500 600 800 1000

25 30 40 50 60.103

Cycles/Sec

S

A v e r a g e p o i n t o f d e t e c t i n g v i b r a t i o n b y a h u m

a n 0 . 1 1




Date: 31-05-10



400

375

200

160

125

100

80

63

50

40

31.5

25

20

16

12.5

10

8

6.3

5

4

3.15

2.5

2.0

1.6

1.25

1.0

250

5.0 6.3 8 10 12.5 16 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400

400

um

300

250

200

150

100

80

60

50

40

30

25

20

15

10

8

6

5

4

3

2.5

2.0

1.5

1.0

P k D i s p

5 6 8 10 15 20 25 30 40 50 60 80 100 150 200 250 300 400

300 400 500 600 1000800 1500 2000 2500 3000 4000 5000 6000 8000 10000 15000 20000Revs/Min

Hz/Sec

MACHINE CLASS III (G)

ISO 2372

[GOOD]

[SATISFACTORY]

[UNSATISFACTORY]

[UNACCEPTABLE]

SPk

Disp

V E L O C I T Y ( e f f ) = 1 1 m

m / s

V

4 . 5

1 . 8

S

A v e r a g e p o i n t o f d e t e c t i n g v i b r a t i o n b y a h u m a n 0 . 1 1




Date: 31-05-10



400

375

200

160

125

100

80

63

50

40

31.5

25

20

16

12.5

10

8

6.3

5

4

3.15

2.5

2.0

1.6

1.25

1.0

250

5.0 6.3 8 10 12.5 16 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400

400

um

300

250

200

150

100

80

60

50

40

30

25

20

15

10

8

6

5

4

3

2.5

2.0

1.5

1.0

P k D

i s p

5 6 8 10 15 20 25 30 40 50 60 80 100 150 200 250 300 400

300 400 500 600 1000800 1500 2000 2500 3000 4000 5000 6000 8000 10000 15000 20000Revs/Min

Hz/Sec

MACHINE CLASS IV (T)

ISO 2372

[GOOD]

[SATISFACTORY]

[UNSATISFACTORY]

[UNACCEPTABLE]

SPk

Disp

V E L O C I T Y ( e f f ) = 1 8 m m / s

V

7

2 . 8

S

A v e r a g e p o i n t o f d e t e c t i n g v i b r a t i o n b y a h u m a n 0 . 1 1




Date: 31-05-10


CHAPTER 13

13. LUBRICATION MANAGEMENT

13.1 Procedure

13.1.1 Lubrication Check Sheets

Check sheets are to be issued on a weekly basis (Day 1 = Saturday) – Ref.Appendix 13.2.

The check sheets are to be issued for each separate Site. The check sheets shouldinclude the sector, plant, system, sub-system, unit, sub-unit and component number,wherever applicable; the type of lubricant; the quantity of lubricant (In a sump orreservoir only); the mode of lubrication (i.e. oil can, grease gun etc.) and thefrequency of lubrication.

The person performing the lubrication checks should make a daily round viaa specified route of the equipment listed on the check sheet and must:

Note levels of lubricant and top-up where necessary

Note the condition of oil reservoirs, bottles, sight glasses and grease nipplesetc., where necessary replacements should be fitted

Note and rectify, or where not possible report, any leaks

Note and verify temperatures of lubricants where temperature probes exist

Note and verify pressures of lubricants where pressure gauges exist


The following establishes the responsibilities and duties of department, sectionor individual.

13.2.1 Production Operator (Daily Checks)

Daily Lube checks should be performed by the Production Operator at the beginningof each morning shift. He should mark the sheets according to his observations andnote the action taken, and sign the sheet for that days checks in the space provided.




Date: 31-05-10


13.2.2 Maintenance Technician (Lube Changes)

Lubrication changes should be performed by the Site Maintenance personnelaccording to the schedule, or in the event of a recommendation made, after thatanalysis reveals some lubrication characteristic deficiencies. The lead man should,on completion, sign the daily check sheet noting on the sheet the quantity of LubeOil used. In addition all other P.M. or W.O. sheets should also be completed.

13.2.3 Production Supervisor

At the end of each week (Friday) he should sign the Lube check sheets in the spaceprovided and note down any necessary remarks. He should then return the sheets

to the Planning Engineer and issue new sheets to his Production Personnel inpreparation for the coming week.

He should also ensure that adequate stocks of lubricant are maintained at his area,and make certain that they are correctly stored and marked. Any barrels or drumsnot having a readable Lube type or damaged to the extent that they are leaking mustbe rejected and returned to the warehouse for exchange.

13.2.4 Planning Engineer

Is responsible for maintaining records and updating the lubrication schedule. He isresponsible for handing out Lube Check Sheets, WOs and PMs for Lube changes,on time. He must ensure that all Lube Check Sheets are returned to him weekly andwithout delay for recording in Maximo, he should also issue new Lube Check Sheetsnot later than 3 days prior to week day one (Saturday). He should issue a monthlybreakdown report (in graphical form) of Lube quantities consumed by machine/skidand Lube type.

13.2.5 Site Maintenance Team leader

Shall monitor the programme and ensure that the Lube sheets are distributedeffectively, and returned on time to the Planning Engineer for recording. Theyshould also review the inspection sheets for any necessary changes required to theschedule.

13.3 Storage and Handling of Lubricants

13.3.1 Storage

Lube oils and greases should be stored in a purpose built building or containersituated close to the main area of the facility so as to aid safe, efficient and easyhandling of the lubricants.




Date: 31-05-10


13.3.2 Handling Equipment

For lubrication inspection and checks the following equipment should be provided:Portable Lubricant Containers for each type of lubricant with lubricant type clearlymarked on each container.

13.3.3 Lubrication Inspection Frequencies

Frequencies

For critical equipment such a generators/drivers, compressors/drivers, transfer/ loading pumps etc. daily checks should be carried out. For other non-critical

equipment manufacturers recommendations or established frequencies shouldbe employed.

Inspection Routes

Inspection routes should be established in order to minimise inspection time. Theseroutes should be formulated and listed in route order on the daily check sheets.

Schedule Reviews

Schedules should be reviewed on an annual basis by FIT and Site Maintenance.

Lubrication Sampling

This practice covers the sampling and analysis of all the Lube oil reservoirs/sumpsfor rotating equipment at ZADCO sites. The practice specifies the following details:

The correct time and frequency for oil samples to be taken

Which equipment requires oil sampling on a regular basis and where on thatequipment the sample should be taken from

Which department/section is responsible for taking the sample and deliveringit to the laboratory

Which department/section is responsible for the correct analysis of the oil anddistribution of the results

Which department/section is responsible for recommending a complete oilchange or reviews and investigates lubrication oil problems




Date: 31-05-10


13.4 Procedure

The sample point must be in the oil line to the equipment (On machines witha separate reservoir) or from a suitable point on a sump. The same point mustbe used each time a sample is taken.

A transparent sample bottle marked with the particular equipment number and onlyused for that particular sample should be used. The bottles label should alsoindicate the Lube oil type.



Is responsible for the co-ordination of Lube oil sampling and should make certainthat sample bottles are delivered, on time, to the facilities that samples are to betaken having collected them from the laboratory. They shall ensure that samplebottles are clean and correctly marked with the machine number and Lube type.

They are also responsible for delivery of samples to the laboratory for analysis andfollow-up for a timely analysis report. They should review the schedule andinvestigate any lubrication problems in liaison with Site Maintenance.

He is also responsible for recording, in the Maximo equipment history files, samplestaken, and distribution of Analysis Request Forms in accordance with the schedule

13.5.2 Laboratory

The laboratory is responsible for the timely analysis of Lube Oil samples, givingwritten reports. The laboratory should supply the ready to use sample bottles.

13.5.3 Maintenance Supervisor

Is responsible for ensuring the collection of Lube oil samples for analysis accordingto the schedule, or by request from BU-MS. He should submit samples along withAnalysis Request Form. He should review schedules and investigation of anylubrication problems in liaison with FI.




Date: 31-05-10


APPENDIX 13.1: EXAMPLE OF LUBE OIL CONSUMPTION CHART

GAS PLANT No. 1 - GT001LUBE OIL CONSUMPTION - HALF YEARLY 1996

0

100

200

300

400

Lube A

Lube B

Lube C

Jan Feb Mar Apr May Jun

200 198 205 195 206 200

150 156 149 151 149 152

350 358 355 356 351 353

L t r s .

C o n s u m e d



Maintenance Management System


APPENDIX 13.2: WEEKLY LUBRICATION CHECK SHEET (Form No. 01/0221/04/F0411.1)

ZADCO

Weekly Lubrication Check Sheet

Site:...........................Plant:.........................System:.....................

Week No.:..................

W.E.F.:.......................

Eqpt. #Day

RemarksLubeType

LubQty.

LubMthd. 1 2 3 4 5 6 7

Signature

(Production Supv.)Signature :..............................

Comments ........................................

.......................................................

.......................................................

Total(Ltrs.)



Maintenance Management System


APPENDIX 13.3: OIL ANALYSIS REPORT FORM (Form No. 01/0221/04/F0411.2)

ABU DHABI NATIONAL OIL COMPANY FOR DISTRIBUTION

USED OIL ANALYSIS REPORT

CUSTOMER :

ATT. :

PHONE NO. :

ENGINE SER-NO :

ENGINE MODEL :

SITE :

STATION NO :

CAPACITY :

BRAND NAME :

DATE :

SAMPLE

SERIAL

NO

DATE

OF

SAMPLE

HRS.

ON

UNIT

HRS ON OILSINCE LAST

MAKEUP

SINCE

LAST

SAMP.

LIT

VIS.

cSt

@

FL-ASH

COC

C

TANmgKOH

PER g

D-

664

INS

OLU

BL-

ES

%

WT

SED

INE

NTS

%

VOL

WA-TER

%

VOL

DI

SP

ER

SA

N-

CY

METAL ANALYSIS

NOTE

CHA-

NGESAM-

PLE40

C

100

C

TBN

mgKOH/g

D-

2896

D-

664Pb Fe Cu Cr Al Si Na

A : THE OIL IS IN GOOD CONDITION AND FIT FOR FURTHER USE.

B : ADDITION OF 25% OF FRESH OIL IS RECOMMENDED TO IMPROVE OIL CHARACTERISTICS.

C : OIL IS IN AN UNSATISFACTORY CONDITION. OIL CHANGE IS RECOMMENDED.

D : DECREASE IN VISCOSITY/FLASH INDICATING FUEL DILUTION/OIL CONTAMINATION.

E : NEUTRALIZATION NO. (TBN/ACIDITY) IS NEARING/EXCEEDED ITS LIMITING VALUE.

F : HIGH SILICON CONTENT. CLEANING OF AIR FILTERS IS RECOMMENDED.

G : RELATIVELY HIGH WEAR METAL CONTENT. INDICATING ENGINE WEAR.

H : RELATIVELY HIGH INSOLUBLES/SEDIMENT IN OIL. INDICATING HIGH SOOT/CONTAMINATION.

I : RELATIVELY HIGH INSOLUBLES/SEDIMENT INDICATING OIL OXIDATION.

J : HIGH WATER/SODIUM CONTENT. CHECK SOURCE OF WATER CONTAMINATION.

K : RELATIVELY LOW DISPERSANCY INDEX. OIL IS NEARING END OF USEFUL LIFE.

L : RELATIVELY HIGH MAKE UP OIL. CHECK FOR SOURCES OF OIL LOSS.

M : HIGH VISCOSITY INDICATING HIGH SOOT CONTENT/OIL OXIDATION.

NOTES :

(*) PLEASE PROVIDE THESE

INFORMATION




Date: 31-05-10


APPENDIX 13.4: REQUEST FOR LUBE OIL ANALYSIS FORM(Form No.01/0221/04/F0411.3)

OIL ANALYSIS REQUEST

EQUIPMENT....................................PYRAMID CODE...............Tag No..................... SITE........................

Priority 1 2 3 4

W.O. No.

REC

OIL TO BE ANALYSED PRODUCT OF............................ TYPE & GRADE......................

TESTS REQUIRED

FLASH POINT

VISCOSITY AT 100 F

210 F

TBN

WATER CONTENT

INSOLUBLES

METAL CONTENT

COLOUR/APPEARANCE

TOTAL ACIDITY

OXIDATION STABILITY

CORROSIVE SULPHUR (COPPER STRIP)

FOAMING TEST

O

O

ORIGINATOR:........................... S.SUPERVISOR:...............................

TEST RESULTS

RECOMMENDATIONS

SUPERVISOR:....................................... S.SUPERVISOR:.........................................

Date of Issue




Date: 31-05-10


CHAPTER 14

14. THERMOGRAPHIC (INFRA RED) INSPECTION

14.1 Introduction

All equipment and processes have patterns of hot and cold which radiate invisiblethermal (infrared) energy. By using an Infrared imaging system, as they aregenerally called, a ‘picture’ of the equipment is produced showing any abnormalheat sources. The detector does this by converting the thermal energy it locates intoelectrical energy, which is then amplified and processed into a visible image that can

be presented onto a viewfinder or monitor. Imaging systems can see temperaturedifferences as small as ½°F or less.

Thermography allows for the quick location and monitoring of problems, allowing thepresentation of critical decision making information in a visual form, making it easyto understand. Produce a picture, either black and white or colour, of the invisiblethermal patterns within a component.

Thermography is non-contact thus making it a safe way to view energised electricalsystems, or moving machinery. Thermography can be used to quickly locate manyequipment and process problems including:

Catastrophic electrical failures

Unscheduled electrical outages or shutdowns

Chronic electrical problems in an equipment item or process

Excessive steam usage

Frozen or plugged product transfer lines

Friction failure in rotating equipment

A fire in a wall or enclosed space

Inability to locate or verify a level in a tank

Replacement of refractory in a boiler, fired heater, etc.

Trouble locating underground lines, and leaking lines

Locating passing valves




Date: 31-05-10


Locating inefficient compressor valves

Assisting in detecting vibration problems

It therefore allows for:

The prediction of failures more accurately

Less or more efficient downtime for maintenance

Most mechanical stresses exhibit both thermal and vibration signatures. Whilstvibration analysis is a more effective diagnostic and monitoring tool, the two used

together are even more valuable.

14.2 Scheduling of Thermographic Inspections

Infrared or Thermographic inspections shall be scheduled on a regular frequency aspart of the predictive maintenance programme. The programme should includesuch inspections as: electrical switchgear, boilers, fired heaters, critical valves,verifying tank level indicators, traps, underground lines, reciprocating compressors,etc.

Equipment should also be monitored prior to a shutdown so that correctmaintenance needs analysis can be carried out, to result in more efficient usageof downtime.

14.3 Analysis of Findings

It should be clearly understood that caution should be exercised in relying solely onmeasured temperature, for example, when prioritising electrical findings, thefollowing should be considered along with the temperature: load, previous history,anticipated usage, ambient changes and cycling are a few of the other factors thatshould be considered.

14.4 Safety

Safety during any activity shall be a primary consideration. The unique needs ofThermographic activities should be considered. Thermographic inspections shouldbe separated from other related inspections, such as visual inspections. Routineinspections should be carried out by a team of two rather than one person.




Date: 31-05-10



14.5.1 Maintenance Team Leader

Shall be responsible for carrying out and controlling the Thermographic InspectionProgramme.

14.5.2 FIT

FIT shall assist Site Maintenance in advising them on scheduling frequencies, andassist in analysis of findings with a view to the remedial action steps.


The scheduling of Thermographic inspections within the Maximo planning system




Date: 31-05-10


CHAPTER 15

15. MACHINERY BALANCING

15.1 Terms

The following terms are used through this procedure.

15.1.1 Balancing

A procedure by which the mass distribution of a rotor is checked and, if necessary,adjusted in order to ensure that the vibration of the journals and/or forces on thebearings at a frequency corresponding to service speed are within specified limits.

15.1.2 Two Plane (Dynamic) Balancing

A procedure by which the mass distribution of a rigid rotor is adjusted in order toensure that the residual dynamic unbalance is within specified limits.

15.1.3 Multi Plane Balancing

As applied to the balancing of flexible rotors, any balancing procedure that requiresunbalance correction in more than two correction planes.

15.1.4 Field Balancing

The process of balancing a rotor in its own bearings and supporting structure ratherthan a balancing machine.

15.1.5 Balancing Machine

A machine that provides a measure of the unbalance in a rotor which can be usedfor adjusting the mass distribution of that rotor mounted on it so that once perrevolution vibratory motion of the journals or force on the bearings can be reduced ifnecessary.

15.1.6 Amount of Balance

The quantitative measure of unbalance in a rotor (referred to a plane), withoutreferring to its angular. It is obtained by taking the product of the unbalance massand the distance of the centre of gravity from the shaft axis.




Date: 31-05-10


15.1.7 Rotor

A body, capable of rotation, generally with journals which are supported by bearings.

15.2 Procedure

15.2.1 Causes of Unbalance

The excess of mass on one side of a rotor is called unbalance. It may be caused bya variety of reasons including:

Tolerances in fabrication, including casting, machining, and assembly

Variation within materials, such as voids, porosity, inclusions, grain, density,and finishes

Non-symmetry of design, including motor windings, part shapes, location, anddensity of finishes

Non-symmetry in use, including distortion, dimensional changes, and shiftingof parts due to rotational stresses, aerodynamic forces, and temperaturechanges

Manufacturing processes are the major source of unbalance. Fabricated parts, suchas fans, often distort non-symmetrically under service conditions.

Centrifugal

Force (F)

Shaft Axis

Unbalance Mass (m)

Figure 15.1: Unbalance Causes Centrifugal Force




Date: 31-05-10


15.2.2 Types of Unbalance

There are four different types of unbalance as described below:

Static Unbalance – Sometimes called force unbalance, exist when the principal axisof inertia is displaced parallel to the shaft axis. It is mainly found in narrow discshaped parts such as flywheels and turbine wheels. It can be corrected by a singlemass correction placed opposite the centre of gravity in a plane perpendicular to theshaft axis and intersecting the CG.

(Ref. Figure 15.2.)

Principal

Inertia Axis

Shaft Axis

Unbalance

CG

Figure 15.2: Static Unbalance

Couple Unbalance – Sometimes called moment unbalance is a condition for whichthe principal axis of inertia intersects the shaft axis at the centre of gravity. It occurswhen two equal unbalanced masses are positioned at opposite ends of a rotor andspaced 180° from each other (Ref. Figure 15.3).

CG

Principal

Inertia AxisShaft Axis

Figure 15.3: Couple Unbalance




Date: 31-05-10


Quasi-Static Unbalance – Is a condition of unbalance where the central principalaxis of inertia intersects the shaft axis at a point other than the centre of gravity (Ref.Figure 15.4).

Principal

Inertia Axis

Shaft Axis

Figure 15.4: Quasi-static Unbalance

Dynamic Unbalance – Is a condition whereby the central principal axis of inertia isneither parallel to, or intersects the shaft axis. It is the most frequently found type ofunbalance (Ref. Figure 15.5).

Principal

Inertia AxisShaft Axis

Unbalanced mass not

diametrically opposed

Figure 15.5: Dynamic Unbalance

15.2.3 CG Displacement and Unbalance

The direct relationship between the displacement of the centre of gravity of a rotorfrom the journal axis, and the resulting unbalance, is fundamentally the mostimportant aspect of balancing. This relationship is the number one consideration intolerance selection, tooling design and determining the balancing procedure.




Date: 31-05-10


15.2.4 Addition/Removal of Mass

Balancing shall be carried out according to internationally recognised industrystandards, or where not available, manufacturers’ standards. The correction of rotorunbalance is usually made by either adding weight or by removing weight.This weight added or removed is often referred to as mass.

The methods used to add mass may include:

Addition of bolted or riveted washers to the element. Should be used whereonly moderate balance quality is required

Addition of mass by welding beads to a suitable surface on the rotor. Careshould be taken that heat generated from the welding process does notdistort the rotor

The methods used to remove mass may include:

Removal by drilling a hole of a defined diameter and to a defined depth.A depth gauge/micrometer should be used to confirm the depth drilled

Removal by milling or shaping. May be used where large corrections arerequired

Removal by grinding. Should be used only where rotor design does not allowfor other methods to be used. It is difficult to ascertain the amount of massremoved and is therefore very much a trial and error method

15.2.5 Field Balancing

Field Balancing Equipment does not generally provide a direct readout of theamount or location of unbalance, despite often being termed as portable balancingequipment. They basically provide an indication of unbalance proportional to the

vibration magnitude.

The amount of magnitude will depend on the transducer and readout system used.Therefore Field Balancing shall only be used where constraints do not allow for therotor balancing to be carried out on a balancing machine in a workshop.

15.2.6 Balance Tolerances

Balance tolerances should be in accordance with manufacturers recommendations.

Where these are not available the following should be used: ISO 1940 ‘BalanceQuality of Rotating Rigid Bodies’, which is equivalent to ANSI S2.19-1975, for rigidrotors, and ISO 5343 for flexible rotors.




Date: 31-05-10



15.3.1 FIT

Shall assist Site Maintenance in obtaining manufacturers recommended balancingtechniques and tolerance, where available, or suitable international standards wherenot available.




Date: 31-05-10


CHAPTER 16

16. PRESSURE SAFETY VALVES

16.1 Terms

The following terms have a specific meaning within this procedure. These termsshould be understood in order for the correct inspection and testing to beaccomplished:

16.1.1 Pressure Safety Valve (PSV)

A valve intended to protect against emergency pressure conditions regardless ofwhether the valve construction and mode of operation place them in the categoryof the safety valve, relief valve, or PSV.

16.1.2 Press Relief Valve (PRV)

A generic term applied to relief valves, safety valves, and PSVs. A PRV is designedto automatically re-close and prevent the flow of fluid. (Note: see also PressureSafety Valve PSV).

16.1.3 Relief Valve

An automatic pressure relieving device, actuated by the static pressure upstream ofthe valve which opens in proportion to the increase in pressure over the openingpressure. A relief valve is primarily used for liquid service.

16.1.4 Safety Valve

An automatic pressure relieving device actuated by the static pressure upstream of

the valve and characterised by rapid full opening or pop-action. Normally used forgas or vapour service.

16.1.5 Safety Relief Valve

An automatic pressure relieving device which may be used as either a relief valveor safety valve, depending upon its application. A safety relief valve is the mostcommon in use.




Date: 31-05-10


16.1.6 Maximum Allowable Working Pressure

The maximum gauge working pressure in a vessel (allowable) at a designatedtemperature. It is the highest pressure at which the primary pressure PSV is setto open.

16.1.7 Operating Pressure

Pressure in either pounds per square inch gauge, kilograms per centimetre squareor bars etc. to which the vessel is normally subjected to in service.

16.1.8 Set Pressure

Is the inlet gauge pressure at which the PSV has been adjusted to open underservice conditions. In liquid service the set pressure is determined by the inletpressure at which the PSV starts to discharge at under service conditions. In gas orvapour service, the set pressure is determined by the inlet pressure at which thePSV will ‘pop’ under service conditions.

16.1.9 Cold Differential Test Pressure

This is the pressure at which the PSV is adjusted to open on the test stand. The

pressure includes the corrections for back pressure and/or temperature serviceconditions.

16.1.10 Simmer

Characterised by the audible passage of gas or vapour across the seating surfaces just prior to the ‘pop’. The difference between this start to open pressure and the setpressure is known as simmer, and is generally expressed as a percentage (%) ofthe set pressure.

16.1.11 Accumulation

Pressure increase over the maximum allowable working pressure of the vesselduring discharge through the PSV, expressed as in OPERATING PRESSUREabove.

16.1.12 Over Pressure

Pressure increase over the set pressure of the primary relieving device. Overpressure is similar to accumulation when the relieving device is set at maximum

allowable working pressure of the vessel. Normally over pressure is expressed asa percentage (%) of the set pressure.




Date: 31-05-10


16.1.13 Blow down

The difference between set pressure and re-seating pressure of a PSV, expressedas a percentage (%) of set pressure.

16.1.14 Lift

The disc rise in a PSV.

16.1.15 Back Pressure

Pressure on the discharge side of a PSV and specified as follows:

Constant – specified as a single constant back pressure

Variable – specified as a variable back pressure range using min./max. limits

16.1.16 Superimposed Back Pressure

The pressure in the discharge header before the PSV opens.

16.1.17 Built Up Back Pressure

Pressure which develops at the valve outlet as a result of flow after the PSV hasopened.

16.1.18 Valve Trim

Includes the nozzle and disc. Standard trim is usually ASTM A 182, grade FF 316Stainless Steel.

16.2 Procedure

16.2.1 PSV Handling

Proper and correct re-installation and handling of plant PSVs is essential. Thefollowing handling format should be rigorously adhered to:




Date: 31-05-10


16.2.2 Storage and Handling of PSVs

Because cleanliness is essential to the satisfactory operation and tightness of a PSVall necessary precautions should be taken to keep out all foreign materials. Valveswhich are not installed immediately upon receipt from the supplier, or after repairin the maintenance shop, should be closed off properly at both inlet and outletports/flanges. Particular care should be taken to keep the valve inlet port clean.

Valves should be stored indoors or at a location where dirt and other forms ofcontamination are at a minimum. Do not permit valves to be thrown on a pile orhaphazardly placed on the ground in such a manner that they can be damaged.Valves should be handled carefully and not subjected to heavy knocks or shocks.

If due consideration is not given to this point, considerable internal damage ormisalignment can result and seat tightness may be adversely affected.

Any valve that has not been certified within 180 days of installation should berecertified prior to installation.

16.2.3 Inspection of Valves before Installation

All PSVs should have a thorough visual inspection for condition before installationand confirmation of certification within the 180 day rule.

The manufacturers’ maintenance manuals should be consulted for details relevantfor the specific valve. Caution should be taken to ensure that all protective materialsinside the valve body or nozzles are removed. Foreign materials clinging to theinside of the nozzle will be blown across the seat when the valve is operated. Someof these materials may damage the seats or be trapped between the seats so asto cause leakage.

16.2.4 Inspection and Cleaning of Systems before Installation

Because foreign materials passing into and through a PSV are damaging, the

system on which the valve is being tested and finally installed must be inspectedand cleaned. New systems are particularly prone to contain welding beads, pipescale and other foreign objects which are inadvertently trapped during constructionof systems and obviously damage the seating the first time a valve opens.

Wherever possible the system should be purged thoroughly before the valve isinstalled. It is recommended that the valve is isolated during pressure testing of thesystem by blanking to avoid damage to the bellows due to excessive back pressure.If gagging is used extreme caution must be exercised to avoid damaging the valveand to ensure that the gag is removed after use.




Date: 31-05-10


16.2.5 PSVs Out of Service

A PSV left on a unit during an extended shutdown (duration of more that 180 days)must be inspected and retested before resumption of operation.

Equipment with dual type PRVs with one valve in isolation, rotation/switch over ofthe PRV back in service should be carried out at least every 180 days .These valvesshould be considered to be in service all the time, when they are in position, whetherisolated or not. Also when a change in operating conditions is to follow theshutdown the inspection interval should be reviewed

16.3 PSV Testing

16.3.1 Practice

PSV testing can be performed at the workshops and the routine testing procedureshould consist of:

Determine the popping and operating pressures for the valve as receivedfrom system specifications

Adjustments and re-tests as necessary for valve acceptance by the

inspection authority

Final test for leakage of the valve and acceptance by the inspection authority

16.3.2 Pressurising Medium

The pressurizing medium to test valves ,should be compatible with the system it isinstalled in, preferably be nitrogen or air, for hydrocarbon systems althoughhydraulic testing should be used to determine the set pressure if the system be seawater or oil.

The use of nitrogen is necessary to check and adjust the valve blow down(difference between popping pressure and re-seating pressure).

16.3.3 Test Equipment

The test equipment should consist of an air source (i.e. compressor, nitrogen),receiver and testing manifold. The air source and receiver should have a capacityof at least 25% greater than the maximum valve test pressure.




Date: 31-05-10


16.3.4 Prior to Testing

Prior to the actual test, all valves should be thoroughly cleaned, blown dry with airand then installed on the manifold for testing. All testing should be controlled andaccepted by an inspector who is qualified and conversant with the relevant codes,standards and safety practices.

16.3.5 Valve Failure

If the valve fails the test and cannot be successfully retested simply by adjusting thespring or nozzle rings, then it should be completely disassembled and repaired inaccordance with the manufacturer’s instructions, then re-assembled and retested.

16.3.6 Valve Sealing

When the valve has been successfully tested, it should be sealed at the cap toprevent unwanted adjustment. The sealing should consist of stainless steel wireand a lead seal, along with a metal tag stating test details as to date of certification,certificate and serial number and test pressure.

The valve should be sealed by the testing inspector or in his presence. All testsshould be recorded on the appropriate form. Test results should be transmitted to

the Production and Maintenance Departments.

16.4 Testing Frequency

16.4.1 General Frequency

Based upon experience, the general frequency of PSV testing in the Energy Industryis grouped, by service, as follows:

Air – 18 to 36 Months

Water – 36 Months

Gas – 24 Months

Hydrocarbons – 24 to 36 Months

A more detailed list by type of service and equipment location is included inAppendix 16.1.




Date: 31-05-10


ZADCO, in the Inspection Guide developed by FIP, has specified the maximumintervals for safety devices (including PSVs) testing. The following table wasdeveloped by FIP and is based upon the Pressure Vessel Inspection Safety Code ofthe Institute of Petroleum (UK):

Inspection Period (Months)Sr.No.

Equipment Grade00

GradeE01

Grade02

Grade03

1 Pressure vessels and vacuumvessels.

24 36 72 108

2 Pressure storage vessels,

tanks.

24 36 72 120

3 Heat exchangers. 24 36 72 108

4 Safety devices. 24 36 60 -

Table 16.1: Class B Equipment Inspection Frequency for PSVs

16.5 Inspection/Testing Schedule

16.5.1 Statutory Class ‘A’ Equipment

PSVs on Class A Equipment, including Boilers and Propane Bullets, shall be subjectto annual inspection/testing.

16.5.2 Class B Equipment

Using the Table above as the maximum period of time between theinspection/testing of PSVs, the actual frequency used in the ZADCO facilities will bebased upon many factors including: operating conditions, environment, potential forfouling or leakage, past experience, historical records, etc.

BU-MS/FI, with the support of Site Maintenance and FIP, will specify theinspection/testing frequency of the PSVs used in the ZADCO facilities. Thefrequencies will be monitored and reviewed, based upon operating experience, andchanges recommended, as required, to ensure the PSVs continue to perform theirfunctions satisfactorily. This shall be in line with the Management of Change policy

16.6 Line PSVs

Line PSVs are normally fixed at 48 months testing frequency unless experience

indicates that a revision is necessary.




Date: 31-05-10


16.7 Records

PSV testing records are required to verify and schedule valve testing. BothInspection authority and maintenance section should maintain PSV testing recordsin order to satisfy the following requirements:

16.7.1 Relief Valve inspection and Testing Records

To maintain ZADCO's Composite Relief Valve Inspection Records.

16.7.2 Scheduling

To initiate scheduling of valves for testing by the Instrument section.

16.7.3 Individual PSV Records

To maintain individual valve testing records to provide historical data on valveconditions during the testing period.

16.7.4 Reports

To facilitate any reports to the production department on their valves by theavailability of the above PSV background data.

16.7.5 PSV Identification

All facility and accommodation PSVs should be stamped on the periphery of theoutlet flange or the body of the valve where the valve has screwed connections.Appendices Production and Maintenance should not accept any valve without its IDnumber stamped on it.


The departments/sections responsible for initiating, witnessing, reviewing designand maintaining the facilities and accommodation PSVs are as follows:


The Planning Section should maintain ZADCO’s composite PSV testing recordsboth individual and Site records. He is also responsible for maintaining the historicaldata/files of valves and the composite valve files.




Date: 31-05-10


Schedules the testing of valves in liaison with Instrument section using thescheduling plan as a guideline. Notification to the Production Superintendentin memo form with PSV numbers, service and locations of the valves to be testedon a quarterly basis, given a month in advance, should be the normal format.

Those valves that can be tested in conjunction with a unit shutdown should beco-ordinated between the Production and Maintenance departments as well as withBU-Ms to facilitate the testing.

Monitor the change over of dual type PSVs and advise operations of change overrequirements to comply with the 180-day rule.

16.8.2 Site Maintenance (Instrumentation)

The Instrument Section is responsible for the actual testing and/or repair of thePSVs.

The sealing of the valves should be carried out by the Instrument Technicianimmediately after passing the test and in the presence of the Third Party Inspector.If an existing valve has failed the test and is thought beyond repair then an ‘identical’valve shall be acquired. In such instances Site Maintenance Team Leader and theThird Party Inspector must convince themselves that the test failure(s) was not dueto poor valve selection or design.

If an identical valve cannot be found, an alternative valve should be selected, afterconsultation between Site Maintenance, BU-MS and Production.

Any valve replacement parts are to be ordered by the senior I&E representative forstorage in the warehouse. He shall also retain the individual PSV test records.

16.8.3 Site Maintenance (Mechanical)

The Mechanical section is responsible for removal and replacement of PSVs in

accordance with handling precautions explained in this practice.




Date: 31-05-10


APPENDIX 16.1: TYPICAL RELIEF VALVE TESTING SCHEDULEFrequency stated in months

SEC

TION LOCATION

AIR

W

ATER

GAS

HYDROCAR

BONS

ACID

CAU

STIC

LPG

HYDRA

ULIC

LUBE

OIL

MISCELLANE

IOUS

1 UTILITIES

a. Aqua Chemb. Pumpsc. Vesselsd. Compressorse. Heat Exchangers

f. General

361836

36

363636

36

36

2418

24

3636

24

36

2418

18

24

2424

18

24

24

24

30

48

48

48

484848

48 482 PROCESS

a. Compressorsb. Heat Exchangersc. Vesselsd. Columnse. Pumpsf. Filtersg. General

18363636

36

363636363636

18

24

24

243636362436

18

18

24

242424

24

242424

1830

48

48

48

48

48

484848 48

3 OIL MOVEMENT

a. Vesselsb. Pumpsc. Lines (PSV)d. Loading Armse. General

36

36

363648

36 24

363648

36 24 24

24

30

4848

3048

4848

48 48

4 WORKSHOPS

a. Mechanicalb. I&E 36

48 48 4848




Date: 31-05-10


APPENDIX 16.2: RELIEF VALVE (FLANGED CONNECTIONS)

2.5 m.m. Dia. HoleFor Sealing

Valve Tag # and Popping

Pressure Stampedon Flange

Size = 10 m.m.(Approx)




Date: 31-05-10


APPENDIX 16.3: RELIEF VALVE (SCREWED CONNECTIONS)

VALVE TAG # AND POPPING

PRESSURE STAMPED

ON BODY

SIZE = 5 M.M.

2.5 M.M. DIA. HOLE

FOR SEALING

PRESSURE STAMPED

ON BODY

SIZE = 5 M.M.

2.5 M.M. DIA. HOLE

FOR SEALING

Male Threaded Connection

Female Threaded Connection




Date: 31-05-10


APPENDIX 16.4: RELIEF VALVE INSPECTION RECORD(Form No. 01/0221/04/F0414.1)

RELIEF VALVE INSPECTION RECORD

Site:..............................

VALVETAG #

LOCATION MFGR. SIZE SETPRES.

DATE INSPECTED& RESET




Date: 31-05-10


APPENDIX 16.5: RELIEF VALVE INSPECTION REPORT(Form No. 01/0221/04/F0414.2)

RELIEF VALVE INSPECTION REPORT

TO: PSM CHECKED BY: P#

SITE: SECTOR: PLANT: DATE: VALVE TAG #:

CONDITION RECEIVED: (Check)

Corroded: Dirty: Clean: Deposits on Guide and/or Disc Holder: Yes - No

Bonnet has Internal Deposits: Yes - NoSeats Corroded: Yes - No

WORK DONE: (Check)

Repair: Lubricate: Machine Seats: Lap Seats:

Machine Disc: Test: Other:

REPLACED PARTS: (Check)

Disc: Seat: Spring: Bellows:

Guide: Stem: Bonnet: Other:

NEW PARTS REQUIRED DURING NEXT OVERHAUL:

COATING: (Check)

Was Valve Coated?: Yes - No

Type of Coating?: Galvanized Molycote Other

c.c.: History File/Instrument Section/Production Supt./PSM




Date: 31-05-10


APPENDIX 16.6: RELIEF VALVE INSPECTION AND TESTING RECORD(Form No. 01/0221/04/F0414.3)

RELIEF VALVE INSPECTION & TESTING RECORD

SITE: SECTOR: PLANT: TAG #: P&ID #

SERVICE: LOCATION:

INLET PRODUCT: OPERATING PRES.: (PSIG) OPERATING TEMP. °C

MAX. TEMP.: °C. TEMP COMPENSATION: °C. OPERATING BACK PRESSURE: (PSIG)

COLD SET PRESSURE (Standard Condition): (PSIG). ACCUMULATION: (%)

INLET SIZE & RATING: (Inches) (p/sq.in.) OUTLET SIZE & RATING: (Inches) (p/sq.in.)

MATERIAL: BODY TRIM SPRING BELLOWS

TEST MEDIUM: TESTED TO: API

MANUFACTURER: SPECIAL FEATURES:

MODEL: SERIAL NO.:

TESTDATE

CONDITIONOF VALVE

PRE. O/HPOP OFF

PRES.

% OFSET

POPPEDAT SET

COMMENTS SIGNATUREINSPECTOR

SIGNATURESUPERVISOR




Date: 31-05-10


CHAPTER 17

17. SAFETY INTERLOCK FUNCTIONAL TEST

17.1 Introduction

The function of a safety interlock is to prevent an unsafe condition arising during anoperating process or activity. Safety interlocks should be designed so that on failureor unsafe condition, the system, process or equipment that is being protectedreverts to the safest mode possible.

The full functionality of a safety interlock is not tested in normal operation until anemergency or unsafe situation arises. It is therefore necessary to perform tests atregular intervals to ensure that all the functions are operative and that in anemergency or unsafe situation the system, process or equipment that is beingprotected shall not cause injury or damage to personnel, the environment or otherplant/equipment.

17.2 Procedure

17.2.1 Test Procedure

Each system which has a safety interlocking sub system(s) or interlocking device(s)shall be identified and a register made of the interlocking devices installed. Eachinterlocking devices shall be uniquely identified and a record maintained of:

Interlocking device number

System/circuit in which installed

Device type (electrical, mechanical, programme, etc.)

Purpose

Consequence/effect on the system when operated

Consequence/effect on the system if it fails to operate

Each of the identified systems shall have a system test procedure to test theoperation of the installed interlocking device(s). The procedure shall allow fortesting of operation in the passive mode (simulation test, with no disruption to thefunction provided) and in the active mode (full functional test).




Date: 31-05-10


The tasks of the test procedures shall be sequenced so that the safety interlockingsystem/device(s) are out of service for the minimum possible time. Where it ispossible to test part of the system, allowing partial operation, this shall be thepreferred method.

The test procedure shall include a positive method for ensuring any bypassoperations, simulating activities, etc., are removed and that the system is left in fulloperational status on completion of the test.

17.3 Preventive Maintenance

The test procedures shall be included in Maximo as part of the master maintenance

plan.

The frequency and mode of test shall be determined by the criticality of the systemfunction and/or guidelines established for the particular system (statutory, companypolicy, etc.). The tests shall be scheduled in the same manner as other plannedmaintenance activities

Prior to commencement of the test, the technician(s) responsible for the testing shallbe fully aware of the scope of work and the necessary precautions required.

Results from the tests shall be reported using the work order (WO). Any repairs

required as a result of the test shall be promptly actioned.

A monthly report shall be prepared by the Planning Engineer detailing the testsperformed and the results of those tests. The report shall be distributed to the SiteMaintenance Team Leader, HSE Engineer and BU-MS

A WO shall also be raised when a safety interlock is bypassed as part of arecognised standard operating practice i.e. plant/equipment start up procedure,testing, filling/emptying etc. (Safety interlocks shall not be bypassed to facilitatenormal operating conditions.) In addition all possible precautions and actions shallbe taken to ensure safety to personnel, the environment and the facilities:

Inform personnel of the actions taken and the additional care required

Provide alternative safety methods or procedures

Place warning signs on associated control desks/consoles/panels/etc., withdetails of the actions taken

fi mms pro 011 maintenance techniques

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