guidance on enclosed space entry & rescue

Edition : 02 /2015

Guidance on Enclosed Space Entry & Rescue


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Published by Theta Marine Consulting

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First edition - A Safety Guide for enclosed space entry 2013 Second edition - Guidance on enclosed space entry & rescue 2015

Copyright © Theta Marine Consulting

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form, by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission of the publisher, except for the quotation of brief passages in reviews.

Although great care has been taken with the writing of the book and production of the volume, neither The Theta Marine Consulting Ltd nor the authors can accept any responsibility for errors or omissions or their consequences.

The Guidance has been prepared to address the subject of the Enclosed Space Entry & rescue. This should not, however, be taken to mean that this document deals comprehensively with all of the concerns that will need to be addressed or even, where a particular matter is addressed, that this document sets out the only definitive view for all situations. Readers should make themselves aware of any local, national or international changes to bylaws, legislation, statutory and administrative requirements that have been introduced which might affect any decisions taken. Also, readers must make themselves aware of the law and jurisdiction of any contracts involved with commercial operations.

The opinions expressed are those of the authors only and are not necessarily to be taken as the policies or views of any organization with which he has or had any connection.

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Table of contents

Introduction ........................................................................................................................ 4

1.0 What is an Enclosed Space? ...................................................................................... 4

2.0 Atmospheric Hazards .................................................................................................. 6

2.1 Products stored in the space: ..................................................................................... 6

2.2 Gas Detectors ............................................................................................................. 11

2.2.1 TankScope ............................................................................................................... 12

2.2.2 Tubes and Multi-Channel Gas detectors ............................................................... 12

2.3 Oxygen ........................................................................................................................ 14

2.3.1 Oxygen Analyzer ..................................................................................................... 15

2.4 Flammable gas ........................................................................................................... 16

2.5 Toxic gas..................................................................................................................... 16

2.5.1 Multimeters .............................................................................................................. 18

2.6 Summary of the Various Gas Measuring Instruments ............................................ 19

3.0 Work being performed in a confined space ............................................................. 20

3.1 Temperature Extremes ............................................................................................... 21

4.0 Systematic Approach to Safety ................................................................................. 22

4.1 General Safety ............................................................................................................ 22

4.2 Correctly Monitor and Record ................................................................................... 23

4.2.1 Risk Assessment ..................................................................................................... 23

4.3 Ventilation ................................................................................................................... 25

4.4 Temperature and Pressure Variation ........................................................................ 27

4.5 Isolation of space ....................................................................................................... 28

5.0 Enclosed Space Entry Permit .................................................................................... 29

5.1 Procedures before entry ............................................................................................ 31

5.2 Procedures During entry ........................................................................................... 32

6.0 Enclosed Space Rescue ............................................................................................ 35

6.1 Enclosed Space Rescue – Action Plan ..................................................................... 36

7.0 Entering an Enclosed Space with an Unsafe Atmosphere ...................................... 39

7.1 Cases Analysis ........................................................................................................... 40

7.2 Further Considerations .............................................................................................. 43

8.0 Completion and Permit Closure ................................................................................ 44

9.0 Duties .......................................................................................................................... 45

10.0 Communication ........................................................................................................ 48

11.0 Closing Summary ..................................................................................................... 49

11.1 Key Points when Preparing to Evaluate the Atmosphere in a Compartment ...... 49

11.2 Evaluating the Atmosphere Secondary Locations................................................. 49

Appendix - I Example of Enclosed Space Entry Permit....................................................51

Appendix – II The dangers of Hydrogen Sulphide in Marine Bunkers.............................53

Appendix - III Example of Safety Poster & Best Practice..................................................57

Appendix - IV IMO Revised Recommendations for Entering Enclosed Spaces Aboard Ship..60

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Introduction Entering an enclosed space is a potentially hazardous activity on board a vessel. A vessel’s Company Management System (CMS) is required to contain “procedures, plans and instructions, including checklists as appropriate, for key shipboard operations concerning the safety of the personnel, ship and protection of the environment. The various tasks should be defined and assigned to qualified personnel”. The CMS will therefore include procedures for entering enclosed spaces. However, in spite of such procedures, incidents resulting in injuries or fatalities continue to occur. This Guidance contains procedures for anyone who may be required to enter an enclosed space. However, it is important to note that the information is intended to supplement, but not replace, CMS procedures as described in Fleet Instruction manual. The basic minimum standard for entry is contained in the 2011 edition of the MCA publication “The Code of safe Working Practices for Merchant Seamen” Chapter -17. Further advice on enclosed space entry may be found in IMO Resolution A.1050(27) “Revised Recommendations for Entering Enclosed Spaces Aboard Ships”. (See Appendix-IV)

1.0 What is an Enclosed Space? Personnel are sometime unsure about the conditions which turn a compartment into an enclosed space, requiring the necessary procedures for safe entry to be followed. In order to assist in the identification of such compartments, IMO has defined an enclosed space as being one which has any of the following characteristics:

Limited openings for entry and exit; Inadequate ventilation; and Is not designed for continuous worker occupancy.

Examples of enclosed spaces may include: Ballast tanks Duct keels Spaces affected by chemical

spill Battery Lockers Engine crankcases Spaces affected by fire Boilers Engine scavenge air receivers Stool spaces Cargo compressor

rooms Foam tanks Void spaces

Waste oil tanks Cargo holds¹ Fuel Oil tanks Cargo pump-room Gas bottle storage lockers Cargo tanks Inter barrier spaces Chain lockers Lube Oil tanks CO2 Rooms Oil spill dispersant tanks Cofferdams Paint lockers Double hull spaces Potable water tanks Dry bulk tanks Sewage tanks ¹ Particularly when carrying oxygen-depleting or noxious cargoes

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It is recommended that a responsible and experienced officer carries out a risk assessment (RA) exercise to identify and record the enclosed spaces on board (as described in Company’s Procedure Manual).The exercise should be repeated periodically as conditions may change over time. If there is any doubt as to whether or not a particular compartment should be listed, it should be treated as an enclosed space until determined otherwise. Compartments next to enclosed spaces should also be considered. IMO defines an “adjacent connected space” as being “a normally unventilated space which is not used for cargo but which may share the same atmospheric characteristics with the enclosed space such as, but not limited to, a cargo space access way”. An example of an adjacent connected space may be a deck house containing a booby hatch leading to a cargo hold. The characteristics of the atmosphere in the deck house may be similar to that of the cargo hold if, for example, the booby hatch lid sealing arrangements are in poor condition and leak, resulting in similar atmospheric conditions within both compartments.

It should also be borne in mind that vent pipes from an enclosed space may pass through compartments which are not necessarily adjacent. If the pipes are not in good condition, these compartments may also be affected. In a recent case, a cargo hold vent pipe ran through a forecastle store some distance away. The oxygen deficient atmosphere from the cargo hold leaked into the forecastle store via a hole in the vent pipe, causing a serious incident. If you are unsure whether or not a compartment is safe to enter you should assume that it is an enclosed space Similarly, tankers constructed with heavy

external deck frames may find that pockets of gas build up outside the access ports if the frames hinder natural surface ventilation. These, and all other possibilities, should be considered when the risk assessment is carried out.

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2.0 Atmospheric Hazards By far the biggest cause of incidents within enclosed spaces is a hazardous atmosphere due to:

Insufficient oxygen to support human life. Flammable (hydrocarbon) gas which may also increase the risk of explosion. Toxic gas which may be fatal in certain concentrations.

Before entering an enclosed space, the amount of oxygen in the atmosphere must be checked. However, the presence of flammable or toxic gas will usually depend on the type of compartment and the properties of the cargoes previously carried. The Material Safety Data Sheets for such cargoes should be consulted to assist in determining the atmospheric hazards that may exist. If there is any doubt regarding the gases or vapors that may be encountered a risk assessment should be carried out. Prior to entry the atmosphere must be tested to check that oxygen levels are satisfactory and that flammable and/or toxic gases, where present, are within acceptable safe limits. When testing for gases it is important that all levels of the space are checked. Some gases are heavier than air (e.g hydrogen sulphide) and some are lighter (eg methane). Concentrations of gas towards the lower parts of an enclosed space will displace air and force it towards the top of the compartment, and vice versa. In addition to testing at different levels within the space, as far as practicable tests should also be carried out at different locations within the space as pockets of gas may still be present even after thorough ventilation. A particular effort should be made if the space contains complex framing arrangements which may restrict the movement of air. In the event that adequate testing of the atmosphere cannot be undertaken from outside the space, it will be necessary to enter the compartment to do so. In such a situation suitable breathing apparatus should be worn and the guidance in the section in this Guidance on “Entry into a Space with an Unsafe Atmosphere” should be followed. If painting or cleaning is to be conducted within an enclosed space, it should be remembered that the paint or cleaning agents may produce solvent gas or other vapors that may be flammable and/or toxic. If gas cutting equipment is to be used inside an enclosed space, the possibility that oxygen and/or acetylene may leak from the hoses or gas torch fittings should be considered. Acetylene gas is lighter than air and will therefore rise to the top of a space. It is also toxic and extremely combustible. 2.1 Products stored in the space: Chemical products In cargo tanks for chemicals it is possible to find all types of chemicals. It is very important that the customer provides a Data Sheet for the product that has been stored in the tank and follows the instructions for safety measures according to this. Health effects as a result of exposure from chemicals in general may cause immediate headache, nausea, fainting and possible death. Long-term exposure to benzene can result in serious blood disorders such as allergy, anemia and leukemia. Chemicals can be absorbed into the structure and/or tank coatings and give off toxic gases at a later stage. When removed or when cleaning out the residue of a stored product, toxic gases can be given off. It is very important to follow the marking and recommendations as given in the Data Sheet to reduce immediate damage as well as the risk for long term damage.

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Petroleum products Most petroleum products are distilled from crude oil which is a product with very high complexity regarding composition of different substances. The composition of crude oil and the products distilled from crude may vary depending on what part of the world the production of crude took place. Petroleum products may be absorbed into the body by inhalation, absorbed through skin or ingested. Effects to health will depend on how high exposure and for how long. Immediate effects of high exposure can include headaches, tiredness, nausea and dizziness. Unconsciousness may occur if exposure is very high. Long-term exposure can result in serious blood disorders such as anemia and leukemia. Be aware that several of the fuels on the market have different additives to prevent e.g. bacteria growth in diesel. These additives may be highly toxic. When the additives are above a certain percentage they are supposed to be included in the Data Sheet. If the amount of additives is very small it does not need to be a part of the Data Sheet. Be aware that several of the fuel producers are very reluctant to reveal what kind of additives they are using in fuels, because this is considered to be business sensitive. Extra care should then be taken with respect to cleaning and measuring for the correct toxic product in diesel and fuel oil tanks. When testing for toxins in a confined space that has contained petroleum products, it may be very difficult to decide what toxic gas to measure for. In general, testing for the most dangerous toxic product in the composition should be carried out. If not otherwise stated on the Data Sheet, benzene is the most toxic part in petroleum products and measuring for this product should be done. If the readings for benzene are within the limits, all the other natural parts of the petroleum product should be within the acceptance limits. Hydrogen sulphide, H2S The risks associated with hydrogen sulphide also need to be considered as this highly toxic gas may be present in cargo tanks, pump-room or pipelines following the carriage of sour crude oil. It may also be present in bunker tanks as described in the relevant bulletin of P & I Club “The Dangers of Hydrogen Sulphide in Marine Bunkers”.

Sewage tanks may also produce hydrogen sulphide. If traces of hydrogen sulphide are detected when the atmosphere is tested, the space should not be entered. It is important to remember that the distinctive smell of rotten eggs associated with hydrogen sulphide is associated with low concentrations of the gas. However, concentrations of hydrogen sulphide exceeding 100 ppm paralyze the olfactory nerves in the nose at which point it is no longer possible to smell it.

This hold vent bellows in a forecastle store had been cut to Drain water. However, it also permitted the oxygen deficient

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atmosphere of the hold to enter the store, leading to 2 fatalities. Hydrogen sulphide is highly toxic and also flammable and is created by the decay of organic matter that is found in sewers and sewage treatment plants. H2S may also be found in crude oil tanks, ballast tanks, void spaces and other tanks that have been empty and decomposition of organic material has taken place. Hydrogen sulphide is heavier than air and has no color but does have a strong “rotten egg” odor at low concentrations. Hydrogen sulphide can affect when inhaled and when passed through the skin. Contact can irritate the eyes. Long-term exposure to low levels can cause pain and redness of the eyes with blurred vision. Breathing hydrogen sulphide can irritate the nose, throat and irritate the lungs causing coughing and/or shortness of breath. Higher exposures can cause a build-up of fluid in the lungs (pulmonary edema), a medical emergency with severe shortness of breath. Exposure can cause nausea, dizziness, confusion, headache and trouble with sleeping. Very high levels can cause immediate death. (see Appendix-II) Hydrogen Sulphide is a HIGHLY FLAMMABLE GAS and a DANGEROUS FIRE HAZARD. At high concentrations H2S paralyses neurons inside the nose and the odor cannot be smelled, hence smelling should not be used as an indicator that the tank is free from hydrogen sulphide. Example: Removal of sludge or mud from a tank-decomposed material can give off deadly hydrogen sulphide gas and/or methane gas.

Benzene Benzene is a highly flammable liquid which occurs naturally in crude oil, natural gas and some ground waters. It is also manufactured from crude oil and is present in crude oil vapors. Benzene evaporates easily, and most people can just detect its distinctive smell at concentrations between 2.5 and 5 ppm in air. Exposure to benzene may occur in oil refineries, chemical and petrochemical plants including offshore installations. Benzene can be absorbed into the body by inhalation, absorbed through skin or ingested. Benzene can affect human beings when inhaled and when passed through the skin. It can irritate the eyes and skin with drying and scaling of the skin. Exposure can irritate the nose and throat. Benzene can cause symptoms of dizziness, light-headedness, headache and vomiting. Convulsions and coma, or sudden death from irregular heart beat, may follow high exposure. Repeated exposure can cause damage to the blood cells (aplastic anemia). Methane Methane is an odorless, colorless gas, or liquid under pressure. It is used as a fuel and in the manufacture of organic chemicals, acetylene, hydrogen cyanide, and hydrogen. Methane is a HIGHLY FLAMMABLE GAS and a DANGEROUS FIRE and EXPLOSION HAZARD.

As a gas, H2S has a vapor density 1.2 times heavier that air and is likely to

hang in suspension for some time after release.

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In addition to being an explosion hazard, very high levels of methane can cause suffocation from lack of oxygen. Skin contact with liquid methane can cause frostbite. Solvents Many solvents, such as kerosene, gasoline, paint strippers, degreasers, are not only flammable, but if inhaled at high concentrations can cause central nervous system (CNS) effects. CNS effects can include dizziness, drowsiness, lack of concentration, confusion, headaches, coma and death. Solvents should never be used as cleaners for the purpose of removing paint or similar from hands. If liquid solvents are in contact with skin, they are absorbed through the skin 10 times more efficiently compared to high content solvent gas absorbed into the body through breathing. LSA’s Naturally occurring radioactive materials have been known to be present in varying concentrations in hydrocarbon reservoirs in a number of areas of the world. It is now recognized that these materials can give rise to radioactive scales (and sludge), which are usually referred to as Low Specific Activity (LSA) scale. The scales tend to be barium sulphate and strontium sulphate, which co-precipitate with naturally occurring radium leached out of the reservoir rock; such scales emit alpha, beta and gamma radiation and this, together with the physical properties of the LSA scale, can give rise to problems if such scales or sludge have to be removed, handled or disposed. Levels of radioactivity can vary from just above background radiation to those requiring restricted areas and classified workers. Hydrogen emission from anodes and/or accumulators: Hydrogen gas (H2) is produced from an electrolytic reaction from zincous-/carbon and alkaline accumulators. A mix of hydrogen gas (H2) and oxygen (O2) may form a highly explosive mixture. Hydrogen gas (H2) is a light gas which displaces oxygen (O2). Oxygen measuring equipment is recommended to be used when entering accumulator room and other enclosures where accumulators are kept. Carbon Monoxide (CO) Exhaust fumes from an engine in an enclosed space are dangerous and often fatal. While lack of Oxygen causes asphyxiation, the gas directly responsible in this instance in Carbon Monoxide (CO) “A Nasty and Sinister Gas”. In the winter, there can be an inexplicable rise in the number of influenza complaints among older people living in poor condition. Winter illness is not always what it seems, and it often has more to do with people trying to keep warm in poorly heated homes, using solid fuel or gas fired heaters with little ventilations, resulting in symptoms similar to flu. They are suffering from carbon monoxide poisoning. This is a serious issue. With the knowledge, spaces can be identified where a similar hazard may gather. A first possibility, or probability, are oil tanks that have a deliberately reduced oxygen content to render them inerted against flammability.

Flammable and combustible mean something that can catch fire and is

able to burn.

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The tanker industry uses exhaust funnel or combustion chamber gases to inert cargo spaces. The gas is low in oxygen, high in nitrogen and carbon dioxide, scrubbed clean of corrosives and particulates, demisted and blown into the cargo tanks. This can also be possible source of carbon monoxide, particularly in crude oil tanks, and must be removed subsequent tank entry of personnel.

The flammable envelope diagram shows that an oxygen level of 11-12% volume is sufficiently inert to prevent the combustion of most hydrocarbon fuels. However, the regulatory requirements for tankers require a maximum oxygen content of 8% by volume measurement. More demanding figures have become industry practice resulting in this figure being brought down to 3-4% oxygen in oil tanker trades. Another situation where carbon monoxide might be a problem is in the inner containment of a combustion furnace gas scrubber, or fan, and the associated pipework. All these spaces, although less likely to be physically entered, can pose a danger to anyone who inhales the contents during a brief internal inspection.

It is easy to confuse the chemical terminology for Carbon dioxide (CO2)

and carbon Monoxide (CO). To avoid running into danger, it is vital to

appreciate the difference between these two gases.

The very simplest hydrocarbon substances such as methane and ethane

gases, propane and butane, etc can build up naturally over time. In the

presence of additional hydrogen and oxygen (water) and temperature

flunctuation, carboxylic acids, are formed, such as formic / methanoic,

acetic / ethanoic, propanoic acids. These contain oxygen, but are prone to

break up and release Carbon Monoxide.

A heated vegetable oil that is rich in palmitic, oleic, linoleic, stearic or

other organic acids may leave behind a quantity of carbon monoxide and

is associated with the common practice of a ship’s crew, entering a tank

that is open to the atmosphere to mop up any remaining puddles. This can,

and has, caused sickness and death.

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The table below illustrates the effect on humans based on various concentrations:

CO ppm Exposure Effect on Humans 50 8 hours Normal permissible exposure limit 200 3 hours Slight headache, discomfort 600 1 hour Headache, discomfort 1.000-2.000 ½ hour Slight heart palpitation 1.000-2.000 1 hour Tendency to stagger 1.000-2.000 2 hours Confusion, nausea, headache 2.000-2.500 ½ hour Unconsciousness

2.2 Gas Detectors There are numerous makes and models of gas detection equipment available. Some may only detect one type of gas, others may detect several. There are also limited life disposable detectors with a sealed battery, and reusable units which require periodic recharging, calibration and servicing. Due to the wide variety of gas detectors that are available, personnel responsible for using such equipment should make sure they are thoroughly familiar with the type of gas detectors on board and how they operate. In addition to understanding the settings, users should be able to distinguish between the various alarms (e.g audible, visual, vibrating) so that they are instantly recognizable, allowing appropriate action to be taken without delay. Gas detectors should not be placed in an atmosphere containing gases for which they were not designed as they may not operate correctly thereafter. The requirements for testing, calibration, servicing and sensor replacement will vary depending on the manufacturer of the equipment and the model. Manufacturers’ recommendations regarding maintenance should always be followed and, where necessary, a suitable stock of gas for testing/calibration should be retained on board. Only competent personnel should be involved with the testing of such equipment, and details of all testing, calibration, servicing and the replacement of sensors should be recorded. Rechargeable batteries should always be fully charged prior to use. If possible, fully charged spare batteries should also be readily to hand. Detectors should always be tested in accordance with manufacturers’ instructions prior to each use.

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2.2.1 TankScope The measurement of hydrocarbon expressed as a percentage of volume is measured using an instrument called a Tankscope. This instrument is used when measuring hydrocarbons in a tank, usually of a C3 propane and C4 butane derivation, when reducing the hydrocarbon content down to or less than 2% volume before gas freeing with fresh air. The figure of 2% volume equates to 100% LFL, from this value, accurate measurements must be made with a combustible gas indicator / explosimeter.

2.2.2 Tubes and Multi-Channel Gas detectors In addition to measuring Oxygen and hydrocarbon content, it is necessary to investigate the presence of any toxic substance. Before measuring for any toxic substance, there must be an understanding of which substances to look for and an awareness of the previous contents of a space is a good starting point. Some contents, such as ammonia, vinyl chloride, toluene, fuming sulphuric acid and other toxic cargoes, give a direct clue for the residues to search for. It should be remembered that the majority of gases are invisible, some like carbon monoxide have no odour, and some substances can be generated by work practices, i.e xylene-rich fumes coming from tank coatings when applied or when heated from an adjacent space. Some substances have a toxicity level lower than their odour threshold, i.e butadiene may not have any odour up to about 1,000 ppm concentration but is considered to be toxic as low as 2 ppm. The search for toxicity in a space is a detective process that requires questioning what properties a substance has, its possible location and concentration in a space before reaching a conclusion as to whether exposure is safe and healthy in the TLV.

The most common way to carry out toxicity measurements is by using test tubes and a small aspirating hand or battery powered pump. The tubes are usually filled with reactive substances

Remember we are aiming for 20.9% Oxygen

and no more than 1% LFL.

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that the incoming vapors may react to and cause a color change, indicating a concentration usually expressed in parts per million. The operator can compare this with the listed TLV. Testing for toxic substances should be undertaken using a reasonable number of apertures or locations in the general environment of a potentially dangerous space. It is also important to take the most aggressive reading found as the one representing that space, not an average of the readings or only those local to where work is being carried out. Great care is necessary in following the test equipment’s operating instructions. When a reading is obtained, confidence that it accurately represents the atmosphere depends on the conditions when using the equipment, including any effects that other substances may cause in the readings of one toxic material. Recent innovations include substance specific sensory devices that show the presence of certain contaminants when installed in a gas measuring unit. In such units, the sensor to use are selected in the same manner as specific Drager Tubes are selected.

The evolution of gas measuring instruments and atmosphere monitoring devices has run parallel to the development of the regulatory requirements and workplace health and safety.

The person in charge of the operations within the space should carry a gas detector capable of measuring all gases which may be encountered. Depending on availability it is also

- When Draeger tube or equal is used for detecting toxic gases the

sampling gas should have sufficient time to pass through the

sampling hose.

- If manual hand rubber pump is used, approximately 4 squeezes are

needed for each meter of the sampling hose.

- If battery driven pumps are used, approximately 10 sec. for each

meter of sampling hose should be sufficient.

Note : The tube methodology is dependent on the

quantity of fresh air and possible contaminant

aspirated through the tube.

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recommended that everyone required to enter the space is provided with a personal gas monitoring device designed to measure oxygen content, and preferably flammable and/or toxic gases as well when necessary. When taking remote samples, care should be taken to acquire samples which provide an accurate representation of the atmosphere inside the space. The sampling pipeline should be long enough to reach all levels within the compartment and should be free of kinks, knots and blockages. When using a hand pump to obtain samples manually, close attention should be paid to pumping a sufficient quantity of the atmosphere through the gas detector to ensure that the readings are reliable. Similarly, units fitted with electric pumps should be run for sufficient time beforehand to allow a fully representative sample to pass through the gas detector. The manufacturer’s instructions should be consulted to determine how many times the hand pump should be squeezed or for how long the electric pump should be run, taking into account the length of sampling hose in use. 2.3 Oxygen The presence of oxygen in the air we breathe is vital to life, therefore verifying that there is sufficient oxygen in an enclosed space prior to entry is crucial. The normal level of oxygen in air is 20.9 % If testing indicates that the amount of oxygen in a compartment is insufficient to sustain life, oxygen displacement or oxygen depletion may have occurred due to one or more reasons. For example:

The rusting or “oxidation” of bare steel. Spaces where bare steel surfaces may be heavily rusted include chain lockers, void spaces and ballast tanks.

If hot work, such as welding or cutting with oxy-acetylene, has been carried out inside a compartment.

The decomposition of organic material within the space, such as a cargo of timber. Fumes released by drying paint. The breathing of personnel, particularly if the space is small and/or poorly ventilated. The use of inert gas such as Nitrogen (N) or fixed fire extinguishing gas such as Carbon

Dioxide (CO2). The development of hydrogen inside ballast tanks generated by the electrolytic reaction

between the steel and the sacrificial anodes. A person inside a space where the oxygen level has fallen to below 19% will begin to suffer drowsiness and nausea, and will start to breathe faster in order to draw the necessary oxygen into their lungs. If the oxygen content falls below 17%, these symptoms will become progressively more pronounced. A level of below 12% will result in unconsciousness and anyone exposed to concentrations of 6% or less may not survive. The effects may be sudden and rapid, explaining why personnel in an oxygen deficient compartment often succumb before they realize what is happening and are unable to exit the space. As a general rule an enclosed space should not be entered unless consistent oxygen readings above 20.0% are obtained. However, more stringent national, flag state or CMS requirements should be followed if applicable. Most gas detectors have two oxygen alarms. The first will sound at around 19% and a second at around 17%. If either of these alarms is heard after entering an enclosed space, the compartment should be evacuated immediately. Excess oxygen in an enclosed space may also impair a person’s ability. In addition, an oxygen-rich atmosphere may present a fire hazard; flammable items such as clothing will burn more

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readily when ignited and may even spontaneously combust. For this reason pure oxygen should never be used to ventilate a space.

Health effects from lack of Oxygen

% O2 Level Effects 22-23.5% Oxygen enriched atmosphere. Disorientation, breathing problems, vision 20.8% Normal Level – Safe for Entry (+/- 0.2%) 19.5% Oxygen deficient atmosphere. Minimum acceptable Oxygen level 15-19% Impaired coordination and breathing. Decreases ability to work strenuously 12-14% Poor judgment. Rapid fatigue and faulty judgment 10-12% Respiration increases. Lips blue 8-10% Mental failure. Fainting, Nausea, unconsciousness, vomiting 6- 8% 8 min : fatal. 6 min : 50% Fatal. 4-5 min: possible recovery 4- 6% Coma in 40 seconds. Death in 3 minutes

Nitrogen is normally used as an inert gas on tankers and may also be employed to inert the cargo holds of bulk carriers. Nitrogen itself is not poisonous and accounts for approximately 78% of fresh air. However, nitrogen used as an inerting agent will displace the oxygen in the atmosphere, making the space hazardous in the process. One deep breath of 100% nitrogen may be fatal.

2.3.1 Oxygen Analyzer In addition to the above stated instruments used in the shipping industry, another one is the Oxygen analyzing meter. This meter is designed to analyze and measure the percentage volume of Oxygen. It is not a simple indicator that states whether or not sufficient oxygen is present. As a minimum, the oxygen meter must measure up to 21% volume, and usually a scale up to 25% volume is provided. It is sensible practice to have oxygen alarm indicators as an additional monitoring safeguard for people in confined spaces. The main issue is measurement of the actual oxygen supply from outside the space before and during entry. An instrument that can be used outside a space, with the operator in fresh air, is preferable to other instruments which need to be inserted into the space to take a reading. Meters with extending remote sensing devices or aspirating probes are recommended.

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2.4 Flammable gas If a tank has contained a hydrocarbon product such as oil or fuel and hydrocarbon gas or vapor is present along with oxygen in quantities sufficient to create a flammable atmosphere, a source of ignition such as a spark will create an explosion. In order to ensure that the atmosphere within the space is safe, the proportion of flammable gas must be measured to verify that it is below the lower limit at which a flammable atmosphere will form. This threshold is termed the Lower Explosive Limit (LEL). A flammable gas detector will measure for the presence of hydrocarbon gases and vapors and provide the reading as a percentage of the LEL. In order to provide an adequate margin of safety, an enclosed space should not be entered if the atmosphere contains flammable gas at a level above 1% of the LEL.

Three crewmembers died after entering this chain Locker where heavy rusting had reduced the oxygen content to less than 10%.

It should be borne in mind that some flammable gas detectors may not provide an accurate reading if the level of oxygen in the compartment is low. Reference should be made to the manufacturer’s manual in this respect. Flammable gas detector alarms are normally triggered by a number of predetermined LEL concentrations. These will depend on the purpose of equipment, the manufacturer and the particular hydrocarbon gas concerned. Typically, flammable gas detector alarms will sound at 10% or 20% of LEL, then at 40% of LEL, and finally at 100% of LEL. It should be remembered that a tank may continue to produce hydrocarbon vapors if cargo or bunker residues are present, particularly if sludge is disturbed or if rust scale is removed.

2.5 Toxic gas Toxic gas may be found in several different types of enclosed space:

In cargo tanks and associated spaces due to residues from a previous cargo. The applicable Material Safety Data Sheet (MSDS) should be consulted to determine which gases may be present.

In cargo tanks due to the presence of an inert gas which contains various toxic trace components such as carbon monoxide or nitrogen dioxide.

In cargo holds containing packaged dangerous goods if damaged due to improper handling, stowage or securing.

In fuel tanks, especially residual oil tanks, as traces of hydrogen sulphide may be present.

In sewage tanks as traces of methane, carbon dioxide, hydrogen sulphide and other toxic gases may exist.

In addition, carbon monoxide, a colorless and odorless toxic gas, is produced when portable generators and other engine driven plant is operated. Such equipment should not be used within an enclosed space.

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Many other toxic gases and vapors are also colorless and odorless. Deciding whether or not a toxic gas is present or if a space is safe for entry should never be determined by smell alone. Toxic gases and vapors are normally measured in parts per million (ppm). However, figures expressed in milligrams per cubic meter (mg/m3) may also be encountered. It may be possible to work in a space containing toxic gas provided the amount does not exceed safe limits. Several different terms are in use for expressing the maximum safe exposure limit including:

Threshold Limit Value (TLV) Occupational Exposure Limit (OEL) Indicative Occupational Exposure Limit Value (IOELV) Workplace Exposure Limit (WEL) Maximum Accepted Concentration (MAC) Permissible Exposure Limit (PEL)

Substance

Workplace Exposure Limit (WEL)

Long Term Exposure Limit (8 hour TWA)

Short term Exposure limit (15 minutes TWA)

ppm

Mg/m3 ppm Mg/m3

Benzene 1 3.25 - -

Carbon Dioxide

5000 9150 15000 27400

Carbon Monoxide

30 35 200 232 Hydrogen Sulphide 5 7 10 14

Phosphine

0.1 0.14 0.2 0.28

Toluene

50 191 100 384 Workplace Exposure Limits (WELs) for some of the more commonly encountered toxic gases on ships The maximum safe exposure limit is defined by the Time Weighted Average (TWA) for both short term exposure (15 minutes) and long term exposure (8 hours). Gas detectors may normally be set to trigger an alarm for either the short term or long term TWA. If the long term TWA is selected, some detector units may also sound an alarm if the level of toxic gas exceeds the short term TWA, thereby providing an early indication of deteriorating atmospheric conditions. It is important to be familiar with the alarm settings for each toxic gas detector on board as the functions may vary. Manufacturers’ manuals should be referred to as necessary. A European Commission Directive on Indicative Occupational Exposure Limit Values specifies the WELs for a large number of toxic gases. The WELs for some of the more common ones are reproduced in a table on the previous page. In addition, there may be flag state or national regulations governing maximum safe exposure limits. If so, such limits should be observed. However, entering an enclosed space is not recommended if the toxic gas readings exceed 50% of the WEL or equivalent.

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If it is necessary to enter an enclosed space which adjoins a compartment containing inert gas, the possibility of leakage (e.g via a defective inert gas line valve) should be taken into account. In such cases it may be prudent to insert blanks into the inert gas line or remove a section of pipe work to ensure that the enclosed space is isolated from the inert gas system.

2.5.1 Multimeters It is now common to find that the individual Oxygen, Hydrocarbon and toxic substance measuring instruments have been replaced by a multimeter device. The multimeter expresses percentage volume of Oxygen and hydrocarbons, but the question is which Hydrocarbons ? The readout often only states flammables, not stating which gas the unit has been calibrated against. It should be remembered that different hydrocarbons have varying flammable ranges. It is not a satisfactory practice to lower a multimeter in a bucket into a space to measure and provide a warning alarm if the findings are outside the acceptable limits. The rapid extraction of the instrument for a visual reading is not a solution to this dilemma either. While most multimeters do have an aspirating extension that can be lowered or probed into a space for a remote readout, the reliability of the sample drawn may not be as sound as one sensed by injecting a sensor head into the space and the electronic readout being seen outside in fresh air.

Multimeters are often fitted with two toxicity measuring sensors that show the parts per million concentration found, typically Hydrogen sulphide and carbon monoxide, though and exchange with other sensors can be made. The operator must give further thought to other contaminants being present, i.e benzene requires another sensor to be fitted or a return to tube measurement.

Never trust one’s own senses to determine if the air in a confined space is

safe ! Many toxic gases and vapors can neither be seen nor smelled, nor

can the level of oxygen present be determined.

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Table showing Gas Monitor Alarm concentrations for common gases

Contaminant1 alarm concentrations o2 (oxygen) Less than 19.5% o2 (oxygen) Greater than 23% co (carbon monoxide) 35 ppm co2 (carbon dioxide) 5,000 ppm h2s (hydrogen sulphide) 10 ppm cI2 (chlorine) 0.5 ppm no2 (nitrogen dioxide) 3.0 ppm nox (oxides of nitrogen) 3.0 ppm ch4 (methane) Greater than 10% of lower explosive limit nh3 (ammonium) 25 ppm concentration 03 (ozone) 0.1 ppm flammable or combustible gas 10% of lower explosive limit1

particulate 10% of lower explosive limit1

1. Where a flammable/combustible gas or particulate is present, the lower explosive limit of the gas/particulate should be known. 2.6 Summary of the Various Gas Measuring Instruments The number and types of gas measuring instruments described above varies between ship types with the greatest range usually found in the chemical bulk liquid tanker trade. Tankers are largely governed by SOLAS requirements, which includes at least two ways to detect and measure gases found in those ship’s respective trades. A summary of the most common types is listed below : Preparation of a space prior to personnel entry :

Oxygen analyzing meter Multimeter may be used Hydrocarbon analyzing meter

Toxic substance sensor Monitoring of a space after preparation :

Oxygen analyzing meter Multimeter may be used Toxic substance sensor The explosimeter is used to test for traces of Hydrocarbons in the preparation and monitoring of a space for personnel entry and for any subsequent work.

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3.0 Work being performed in a confined space Examples of such include welding, cutting, brazing, painting, scraping, sand blasting and degreasing. Toxic atmospheres are generated in various processes. For example, cleaning solvents are used in many industries for cleaning/degreasing. The vapors from these solvents are very toxic in a confined space. It is also important to be aware that hot work carried out consumes oxygen. Welding Hot work on all surfaces with coating will create several gases which may be very toxic. This gas may come from hot work being carried out in a tank adjacent to the space being surveyed. Coating Special attention should be paid when spray coating is carried out in the area of the survey. Spray coating where small size particles are mixed with air will lead to high toxic exposure if inhaled. Grinding Grinding may cause miscellaneous compositions of dust. Absorption of metal dust into the body through inhalation is dependent on the physical and chemical properties and the size of the particles. Dust like this may cause metal fume fever and bronchitis. Sandblasting The dangers connected to sandblasting very much depend on the object’s substance and the size and containment of grit. Several grits used for sandblasting contain carcinogenic substances like quartz, nickel, lead and lead compound. During sandblasting the containment of carcinogenic chemicals may increase depending on the surface of the sandblasted area. Hydro blasting Hydro blasting may create aerosols. Aerosols are dispersion of solid or liquid particles in air which are small enough to stay in the air for a long period of time. Aerosols may transport reactive chemicals deep into the lungs in a way that causes very high exposure. Aerosols may be produced from dust, dirt and cleaning chemicals in the process of high-pressure cleaning of miscellaneous surfaces. NDT operations Chemicals from NDT operations may also be dangerous. Most ultrasonic thickness measuring equipment is not intrinsically safe.

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3.1 Temperature Extremes Extremely hot or cold temperatures may present another problem for anyone working in the enclosed space : The temperature of the working environment, and the length of time personnel will be in the space, should be taken into consideration when conducting a risk assessment in advance of entry. Extreme hot or cold can reduce a person’s safety and situational awareness.

Monitor personnel’s condition when working in extreme hot or cold enclosed spaces

Heat – A person working in a very hot environment loses body water and salt through sweat. This loss should be compensated by water and salt intake. Fluid intake should equal fluid loss. On average, about one liter of water each hour may be required to replace the fluid loss. Plenty of drinking water should be available on the job site and workers should be encouraged to drink water every 15 to 20 minutes, even if they do not feel thirsty. Drinks specially designed to replace body fluids and electrolytes may be taken. Alcoholic drinks should NEVER be consumed, as alcohol dehydrates the body. Cold Temperature – At very cold temperatures, the most serious concern is the risk of hypothermia or dangerously low body temperature. Warning signs of hypothermia include nausea, fatigue, dizziness, irritability and euphoria. Sufferers may experience pain in their extremities (for example hands, feet, and ears) and severe shivering. Presence of Dust – A high concentration of dust in an enclosed space is hazardous to health and can cause breathing difficulties. It can also hamper visibility and work. Toxic dust can be harmful even in small concentrations. The use of machinery and powered tools may require special precautions, such as the provision of dust extraction for a portable grinder.

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4.0 Systematic Approach to Safety It is important to consider the risks to health and safety of any work-based activity, whether ashore or onboard ship. This broadly involves the following steps :

1. Hazard identification (JHA) 2. Risk Assessment (RA) 3. Checklist 4. Permit Certificate (PER) 5. Monitoring of activity 6. Record of completion.

4.1 General Safety In addition to the atmospheric hazards associated with enclosed spaces, such compartments are often unlit, cramped, have limited access and may have slippery surfaces due to the presence of water, mud, cargo residues or rust scale. Often the edges of frames, decks and stringers are exposed, and there may be unguarded lightening holes within the space requiring additional vigilance. If due to work at a height, additional precautionary measures including a Permit to Work may be necessary. The following Personal Protective Equipment (PPE) is recommended as a minimum for enclosed space entry. However, the requirements of the CMS should also be followed in this regard:

Overalls, with high visibility reflective markings. Safety boots. Hard hat with chin strap. Eye protection; either safety glasses or goggles. Gloves, unless deemed to be a hindrance on slippery ladders. Torch with a suitable strap so that it may be slung around the body to prevent it from

being dropped or lost. If due to be used in an atmosphere that may be flammable, the torch should also be intrinsically safe (ie equipment that has been designed and approved for use in flammable atmospheres).

Where available, a personal gas detector for each person entering the space.

Depending on the risk assessment : Ear protectors, particularly if due to work in a high noise environment. Protective filter mask if, for example, the atmosphere contains particles. However, filter

masks should never be used as a life support device in atmospheres which are deficient in oxygen or contain toxic and/or flammable gas.

Competence – can be difficult to define, but typically includes the following

approaches to work :

Knowing what to look for – education and training.

Recognizing key factors – awake and interested.

Assessing and deciding what to do, including when to leave things

as they are if the situation is safe and healthy.

Taking well prepared and practiced actions.

Experience and good judgment – often related to a previous

incident.

Continued observation and repetition of the above process.

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More suitable protective clothing and eyewear if personnel are to enter a cargo tank which contains chemical residues where there may be a risk of skin absorption.

This non-intrinsically safe halogen lamp was placed just inside the door of a boiler steam drum shortly after it was opened for inspection following a chemical clean. The tank atmosphere exploded causing fatal injuries to one of the personnel outside the steam drum door.

4.2 Correctly Monitor and Record A management group should be formed and structured as follows by separate individuals (as described in the relevant chapter of Company’s Fleet Instruction Manual ) , i.e it is not acceptable that one person can be delegated responsible Officer and also the team leader of the entry group : Overall Responsibility Master Delegated responsible Officer Chief officer or Chief Engineer Team Leader of entry group A responsible, communicative experienced

and knowledgeable person, officer or rating Tank Entrance safety standby A responsible, communicative person Entry Team Individuals working within the strict

conditions of the permit, well informed of the hazards, under the supervision and direction of the Entry Team Leader, observed and in communication with the Safety standby

Central Control Recorder The watch officer of the bridge or deck, directly contactable, deliberately recording times, names, detailing the entry and exit of each Entry team Member with immediate access to the overall responsible Master

The type of management group structure involves a number of people in preparing the task. It compounds the assessment of risk, creates greater respect for the job and prevents a casual approach. The type of structure may not be possible for the crew of smaller ships such as coasters, where many confined space incidents occur.

4.2.1 Risk Assessment There are many ways of conducting a Risk Assessment (RA). The company provide guidance on how to carry out risk assessment and any hazard identification (HAZID) techniques that must

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be used (as described in CPM Chapter-17). One of the outcomes of a risk assessment should be a hazard register. The hazard register records all the hazards that have been identified by the various HAZID techniques, showing representative causes, consequences and safeguards for each. It is sensible to maintain a portfolio of hazard registers specific to tasks or operations on your ship, including entry into enclosed spaces (RA Library). When a non-routine or particularly hazardous activity is to be conducted, the register can be referred to in order to see which hazards apply and the safety measures to be put in place. Whilst not all of the hazards may be present on each occasion, there may be additional hazards that have not previously been identified. The register is therefore a guidance document to be consulted, and should not replace an assessment of the risks on each occasion. Such registers should be “living documents” – continually reviewed and updated. The following table is an example of a list of typical enclosed space entry hazards, methods for controlling the hazards and mitigating measures – steps that can be taken that should reduce the impact of any incident :

Incident Cause Preventive Measure

Mitigating Measure

Person entering collapses in the space

Unguarded edges. Structural failure of ladders and platforms. Unsafe use of ladders / staging .

All lines leading into the space secured. Space emptied Space remotely cleaned prior to entry if possible, i.e COW washing of oil tanks or filling tanks with water then pumping out. Atmosphere tested and found safe prior to entry Atmosphere tested at regular intervals. Continuous verification of the space.

Personnel entering the space trained in enclosed space entry procedures. Attendant at entrance – contact with bridge. Regular communication between attendant and entry personnel. Emergency signal established. Entrants wearing personal monitor. Rescue equipment on stand-by including breathing apparatus, harness, and lifeline.

Fire / explosion in the space

Dust Cloud Flammable atmosphere Hot work Equipment failure Oxygen-rich atmosphere Hydrogen rich

Monitor atmosphere Use only intrinsically safe equipment in potentially flammable atmospheres i.e fuel oil tanks. Follow hot work procedures. Do not use defective equipment. Do not ventilate with pure oxygen.

Sufficient personnel on board to form a fire party. Training and drills in fire fighting First aid equipment.

Slip / trip Poor lighting Poor housekeeping. Inadequate PPE Hazardous structural arrangement. Worker fatigue. Slippery surfaces. Poor visibility from dust / smoke, mist, etc.

Good lighting arrangements Monitor and maintain good housekeeping. Relevant PPE worn as appropriate. Briefing / awareness of space arrangement before entry. Assessment of personnel before entry and throughout. Proper rest periods and rehydration. Good ventilation and dust prevention measures.

Stretcher and first aid kit available. Drills in first aid incidents, including procedures for communication to shore- side assistance.

Fall from height Unguarded edges. structural failure of

Wear fall prevention devices where

Stretcher and first aid kit available.

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ladders and platforms. Unsafe use of ladders / staging.

appropriate. Guards / rails on platforms. Inspection of ladders and platforms. Training in the use of portable ladders and staging. Personnel assisting where portable ladders are used where equipment is to be moved. Proper securing of portable ladders and staging.

Drills in first aid incidents, including procedures for communication to shore- side assistance.

Illness of person entering Dust Smoke Fumes Noise Humidity / heat / cold Phobias, fatigue, mental and physical condition. Heat fatigue.

Monitor and ventilate atmosphere. Ear protection, personal protective equipment (PPE). Rehydration (drinks) / rest periods / adequate clothing / PPE. Suitability of crew according to risk assessment before entry. Pre-employment medical examinations.

Rescue equipment not usable

Falling objects Electrical / Mechanical equipment in the space. equipment does not fit through access.

Harnesses for tools and equipment at height. Hard hats (PPE). Pumps and mechanical equipment in the space isolated. Analysis of the job hazards and equipment before entry. Protection of electrical equipment from fluids. Drills on board confirm suitability of rescue equipment. Discussion before entry about available rescue equipment for the space.

4.3 Ventilation Mechanical ventilation is crucial to making safe the atmosphere within a space. The more air changes that can be carried out prior to entry the better. So far as is safe and practicable, all accesses to the space should be opened to maximize air flow and aid the evacuation of the space in an emergency. Suitable signs and barriers should be placed near each access prohibiting entry, and any openings in the deck should be fenced off to prevent injury. Before entering cargo holds the fixed ventilation fans should be turned on (where fitted). Ventilation may be further improved by partially opening the hatch covers if it is safe to do so.

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If portable fans are used, the suction arrangements should be placed in the open, well clear of all accesses to ensure that the space is provided with a clean supply of fresh air. Ducting to transfer fresh air to the worksite should be rigged where possible. Intrinsically safe fans should be used where necessary. Inert gas fans should not be used to ventilate cargo tanks as they may introduce traces of inert gas into the compartment. If access to ballast tanks is required, entering the tanks soon after they have been emptied is preferable as the action of removing the ballast will draw fresh air into the space. However, it will still be necessary to follow the applicable SMS enclosed space entry procedures including ventilating the tanks and testing the atmosphere beforehand. Ventilation should be stopped sufficiently in advance of testing to allow the atmosphere within the space to stabilize. Ten minutes or more should suffice. If the readings are satisfactory, ventilation should be resumed. Ventilation should continue until work inside the enclosed space has been completed and the compartment has been vacated. Should the ventilation arrangements fail while personnel are inside an enclosed space, everyone should leave the compartment immediately. Such a situation invalidates the applicable Permit to Work.

Warning :

Never use pure Oxygen to ventilate

Never store or place compressed Oxygen tanks in an enclosed space.

De-Ballasting a tank does not guarantee a safe atmosphere in the tank

Ventilation and testing of its atmosphere is still required.

Inert gas fans should not be used to provide fresh air ventilation to tanks with inert gas arrangements because contaminants from the inert gas lines could be introduced into the space.

Natural ventilation may be acceptable if, for example, two accesses are open to allow a through draft of good air. Caution should be taken in large enclosed spaces without forced ventilation as

A supply of non-contaminated fresh air is the most important requirement at

every location that might be visited or worked in while onboard.

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there may be pockets of poor quality air that have not been displaced with good air. Oxygen monitors must always be used to check the atmosphere in naturally ventilated enclosed spaces. 4.4 Temperature and Pressure Variation Variation in temperature and pressure may be coincidental, sharing the same cause or circumstances. For example, during hot water tank washing, both the heat applied to the residue in a tank and the mechanical agitation can change the residue from a solid to a liquid then a vapor. The pressure of that release would be seen in a tank with accurate pressure monitoring and, as the vapor is above Standard Temperature and Pressure (STP), it tends to rise. When a vapor that is heavier than air at STP is heated, the vapor will rise, cool and fall back down. Similar vapor movement is likely when liquid is loaded into a tank. As most vapors are heavier than air, they tend to rise and then come down. On a ship sailing in a tropical zone, vapor that is heavier and denser than air in a tank will contract in volume if the ship moves to a cold climate. The vapor may then condense to form a liquid. However, the opposite will occur with a small quantity of liquid at the bottom of a tank or container in a cold weather location. Transporting an empty tank to a warm port to load a pure high value, non-contaminated cargo allows any small amount of liquid content to turn into vapor and contaminate the incoming liquid.

The physical effect of phase change from solid to liquid to vapor is accompanied by an expansion in volume. The reverse occurs when the temperature is reduced. The only exception is the temperature reduction of water, when the phase change from liquid to solid causes expansion. Liquids, solids, emulsions, mud, scale or sludge, when heated or disturbed, will release vapor. An important point is that water can hold other components. Some may be harmful to personnel walking through any water pools at the bottom of a tank, resulting in contaminated fresh air.

If personnel require knee-high boots to enter a tank, it suggests that there is a

residual liquid and that the tank is not safe to enter.

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4.5 Isolation of space Isolation of a confined space is a process where the space is removed from service by one or more of the following. Locking out: Electrical sources, preferably at disconnect switches remote from the equipment. Blanking and bleeding, securing valves: Cargo, ballast, IGS, pneumatic and hydraulic lines. The inert gas branch should be blanked off. The appropriate blanking is to be checked at each tank if entry is required while inerting, or gas freeing of other tanks is taking place, or if any other tanks are inerted or contain hydrocarbons. An alternative to pipe blanking would be to remove a section of the branch line. Disconnecting: Mechanical linkages on shaft-driven equipment where possible. Securing: Mechanical moving parts within confined spaces with latches, chains, chocks, blocks, or other devices. Notice boards Appropriate notices, which clearly specify which space and prevailing requirements agreed upon for confined space entry, should be displayed in prominent locations such as bridge, cargo control room, and/or engine control room. Blanking, locking and securing of equipment:

Signage There is no internationally recognized marine signage that depicts – ENCLOSED or CONFINED SPACES. Different signs have been promulgated and many ships denote the danger by the use of painting warning notices or stencils. This Guidance suggests one design, but there are many that could be used. The important point is that the crew are warned that the space is enclosed and that entry requires an entry permit and authorization to enter. Companies and ships Officers should identify enclosed spaces on board their ships and ensure that appropriate warning signage is used.

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5.0 Enclosed Space Entry Permit CMS procedures should always be followed when entering an enclosed space. A risk assessment should also be carried out where deemed necessary or if required by the CMS, and a Permit to Work must be obtained prior to entry (See Appendix-I). Ideally, and before anyone enters the space, the Permit to Work provisions should be checked carefully by the person in charge of the task due to be carried out inside the compartment and verified by the responsible person in overall charge of the operation who should remain outside throughout. This will minimize the possibility of key safeguards being overlooked. A Permit to Work for an enclosed space should be issued for a defined period. Open ended permits are unacceptable. It is recommended that Permits to Work are issued for a period not exceeding 8 hours, or less if required by the CMS or as determined by a risk assessment. When entering an enclosed space a suitably experienced crew member should be stationed at the entrance to the space. The IMO term for this person is an “attendant”, described as being “a person who is suitably trained within the safety management system, maintains a watch over those entering the enclosed space, maintains communications with those inside the space and initiates the emergency procedures in the event of an incident occurring”. The attendant should remain by the entrance until all personnel have left the space.

There should be an agreed means of communication between those in the space and the attendant, for example by using visual signals or two-way handheld radios. The reporting interval should be understood by all personnel involved. There should also be a means of communication between the attendant and whoever is on watch on the bridge, in the cargo control room or in the engine room so that immediate assistance can be summoned in an emergency.

Ensure that all tools, equipment and materials are Removed from the space upon completion of work.

If the attendant is changed, a thorough handover should take place. The new attendant should be provided with all relevant information including the number of people in the space, the method of communication with those inside, the reporting interval and the means of summoning assistance in case a rescue team is required. Should there be a change in conditions, particularly if the atmosphere in the space deteriorates, a gas monitoring device alarm is heard or the ventilation arrangements fail, the Permit to Work is rendered invalid and everyone must leave the space immediately. Personnel may only re-enter the compartment once the situation has been rectified, the atmosphere has been made safe and a new Permit to Work has been issued.

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Check the ship plans before entering the space for the first time.

Upon completion of the work, all personnel should leave the space promptly taking with them all tools, equipment and materials. The attendant should perform a head count thereafter. All accesses to the space should then be closed. Manhole sealing arrangements should be cleared of debris and new gaskets fitted where possible. The lids should be re-secured and opposite bolts tightened sequentially. In the case of ballast tanks manholes it is recommended that the tanks are tested hydrostatically at the earliest opportunity to ensure that there are no leaks. If an adjacent space contains cargo, such a test may be postponed until it is empty. Once the space has been closed, any valves that were locked shut should be put back into service. Warning notices and blanks inserted into lines should be removed, and any disconnected sections of pipe should be refitted. Gas detection equipment should be retested and calibrated in line with manufacturer instructions before being stowed away ready for the next occasion, and assigned for servicing if required. Similarly, all emergency tank rescue equipment should be returned to its storage location. Copies of the Permits to Work issued for the enclosed space entry should be filed in accordance with CMS requirements.

The permit should be relevant and as accurate as possible. It should state the location and details of the work to be done, the nature and results of any preliminary tests carried out, the measures undertaken to make the job safe and the safeguards that need to be taken during the operation.

A permit to work, does not in itself make the job safe, but contributes to measures

for safe working. The enclosed space entry permit relates to allowing people into

the space – the work to be conducted in the space requires a separate evaluation. Theta

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The permit should specify the period of its validity (which should not exceed 24 hours) and any time limits applicable to the work which it authorizes.

Only the work specified on the permit should be undertaken Before signing the permit, the authorizing officer should ensure that all measures

specified as necessary have been taken The authorizing officer retains responsibility for the work until he has either cancelled the

permit or formally transferred it to another authorized person who should be made fully conversant with the situation. Anyone who takes over, either as a matter of routine or in an emergency, from the authorizing officer, should sign the permit to indicate transfer of full responsibility

The person responsible for carrying out the specified work should countersign the permit to indicate his understanding of the safety precautions to be observed

On completion of the work, that person should notify the responsible officer and get the permit cancelled

The person carrying out the specified work should not be the same person as the authorizing officer

5.1 Procedures before entry

Always use an enclosed space entry permit

Access to and within the space should be adequate and well illuminated. No source of ignition should be taken into the space unless the master or responsible officer is satisfied that it is safe to do so. Use only equipment that is certified intrinsically safe in potentially flammable atmospheres, especially in fuel oil tanks. In all cases, rescue and available resuscitation equipment should be positioned ready for use at the entrance to the space. Rescue equipment means breathing apparatus together with fully charged spare cylinders of air, life lines and rescue harnesses, and torches or lamps, approved for use in a flammable atmosphere. A means of hoisting an incapacitated person from the confined space may be required. The number of personnel entering the space should be limited to those who need to work in the space. When necessary, a rescue harness should be worn to facilitate recovery in the event of an accident.

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At least one attendant should be detailed to remain at the entrance to the space while it is occupied. An agreed and tested system of communication should be established between any person entering the space and the attendant at the entrance, and between the attendant at the entrance to the space and the officer on watch. Before entry is permitted it should be established that entry with breathing apparatus is possible. Any potential difficulty of movement in any part of the space as a result of breathing apparatus or lifelines or rescue harnesses being used or any other problems that would arise if an incapacitated person had to be removed from the space should be carefully considered and the risks minimized. Lifelines should be long enough for the purpose and capable of being firmly attached to the harness, but the wearer should be able to detach them easily should they become tangled. 5.2 Procedures During entry

Always use an enclosed space entry permit. Do not enter a tank without one.

Ventilation should continue while the space is occupied and during temporary breaks. In the event of a failure of the ventilation system, any personnel in the space should leave immediately. Good natural ventilation is acceptable if for example two accesses are open so there is a through draft of fresh air. Care needs to be taken in large enclosed spaces without forced ventilation as there may be pockets of poor quality air that have not been replaced by good air. The atmosphere should be tested periodically while the space is occupied and personnel should be instructed to leave the space should there be any deterioration of conditions. If unforeseen difficulties or hazards develop, the work should be stopped and the space evacuated so that the situation can be reassessed. Permits should be withdrawn and only reissued, with any appropriate revisions, after the situation has been reassessed. If any worker in a space feels in any way adversely affected they should give the prearranged signal to the attendant standing by the entrance and immediately leave the space.

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Should an emergency occur, the alarm should be sounded so that back-up is immediately available to the rescue team. Under no circumstances should the attendant enter the space before help has arrived and the situation has been evaluated to ensure the safety of rescuers who may have to enter the space. If air is being supplied through an air line to a person who is unwell, a check should be made immediately that the air supply is being maintained at the correct pressure. Once the casualty is reached, checking of the air supply must be the first priority. Unless he is gravely injured and in imminent danger, the casualty’s condition should be properly assessed before being removed.

Enclosed spaces are potentially dangerous

Noise Noise in an enclosed space can be amplified by the design and acoustic properties of the space. Excessive noise can affect communication, such as a shouted warning going unheard or misinterpreted. Falling objects Workers in enclosed spaces should be mindful of the possibility of objects falling, particularly in spaces which have a topside opening, and where work is being carried out above the worker. Slick/wet surfaces Slips and falls can occur on a wet surface causing injury or death. Corroded and unstable platforms and ladders are a risk.

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The Table below provides an overview of entry procedures : Before Entry All parties to discuss the job to be done in the space

What are the hazards of the space and how can they be controlled ? What are the hazards of the job and how can they be controlled ? Risk Assessment

Document the hazards and necessary safety measures and controls. Secure the Space

Empty the space if necessary and take steps to prevent the space filling up : Lock out valves and pumps, and Place notices forbidding their operation. Is the space adjacent to other tanks, holds, or pipelines which if not

secure could present a danger ? Ventilate

Allow sufficient time for the space to be thoroughly ventilated naturally or mechanically. Guard any openings against accidental and unauthorized entry. Test Test the atmosphere in the space for Oxygen content and the presence of flammable and toxic gases or vapors. Do not enter until the atmosphere has been determined to be safe. Permit – Complete an enclosed space entry permit to work (PER-006), confirming that : The hazards of the job and of the space have been dealt with. The atmosphere in the space is safe and ventilated. The space will be adequately illuminated. An attendant at the entrance has been appointed. Communications have been established between bridge and entry point, and entry point and entry party. Emergency rescue equipment is available at the entrance and there are sufficient personnel on board to form a rescue party. All personnel involved are aware of the task and the hazards, and are competent in their role.

During Entry Ensure the space is suitably illuminated. Wear the right PPE Continue to ventilate the space Test the atmosphere at regular intervals Communicate regularly Be alert, and leave the space when requested or if you fell ill.

After Entry Ensure all equipment and personnel are removed from the space. Close the access of the space to prevent unauthorized entry. Close the entry permit Reinstate any systems as appropriate.

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6.0 Enclosed Space Rescue It is natural for humans to try and rescue someone believed to be in danger. However many seafarers and stevedores have lost their lives by following their instincts and entering an enclosed space without thinking in order to rescue a collapsed colleague. More than half of all personnel who have died in enclosed spaces were would-be rescuers. In many instances the rescuer had acted alone after mistakenly thinking that the person lying at the bottom of the compartment had slipped and fallen while using the ladder or tripped and knocked themselves out, not realizing that they had collapsed due to the deficient atmosphere

inside the space. Although assumptions of this kind may sometimes be correct, chances must never be taken and enclosed space rescue procedures should always be followed regardless of the actual cause of the incident. Similarly, the attendant stationed outside the enclosed space should never enter the compartment if those inside appear to be getting in to difficulty. Every rescue attempt should be safely managed so that the rescuers do not become additional victims, compounding the size and complexity of the rescue operation.

Rescue equipment should be placed by the entrance to the enclosed space before personnel start work, ready for immediate use.

The restricted manhole opening into this chain locker Made it difficult to access the space whilst wearing SCBA and to recover the persons who had collapsed Inside .

Such equipment may include:

Oxygen/flammable gas/toxic gas detectors. Full rescue harnesses. Lifelines of sufficient length. Additional communication equipment. Self-Contained Breathing Apparatus (SCBA) - ideally positive pressure with spare

bottles, or airline breathing apparatus. Protective clothing, particularly where contact with hazardous substances is possible. Torches, intrinsically safe where necessary. Tripod and man-riding winch gear - where available, and if vertical rescue is possible. Neil Robertson stretcher or equivalent. Resuscitator. First aid kit.

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Members of the enclosed space rescue team should not be tasked with working inside the compartment and should be available to provide rapid assistance without delay. They should also be properly drilled in enclosed space rescue and be familiar with the use of the SCBA and airline breathing apparatus available on board. The person in charge of the enclosed space rescue team should direct the rescue efforts from the entrance to the compartment and should not enter the space itself. Sufficient personnel should be available outside the compartment to assist, particularly if casualties in Neil Robertson stretchers need to be lifted out. Under no circumstances should Emergency Life Support Apparatus (ELSA) be worn by anyone rescuing a casualty from an enclosed space. There have been many deaths and near-fatalities involving personnel who have attempted to rescue a colleague while wearing an ELSA. During a rescue attempt, personnel wearing SCBA may not be able to enter the compartment easily if the access arrangements are restricted. It may be necessary for the SCBA to be passed through the access separately to the mask wearer inside. Some manufacturers now produce smaller SCBA sets that are designed to be donned rapidly and enable easier access to spaces with limited openings. Entering an enclosed space with a confined entrance should be practiced during rescue drills. In the event of an enclosed space incident in port or at anchor, additional assistance from the emergency services ashore should be requested at the earliest opportunity. Enclosed space rescue training is not, at present, a statutory requirement under SOLAS, and very few countries require enclosed space rescue drills to be conducted in order to comply with national or flag state requirements. Consequently Members are encouraged to require their vessels to carry out regular enclosed space entry training during shipboard emergency drills, perhaps once every two months, if they are not doing so already. Amendments to SOLAS Chapter III to mandate the conduct of periodic enclosed space rescue training are being discussed by the IMO and are expected to come into force in the not too distant future.

6.1 Enclosed Space Rescue – Action Plan

Safety Precautions - Do not rush in - Do not try to act alone – do not enter until help arrives. - Call back-up - Stand-by team to assist - Ventilate the atmosphere.

Emergency Response

A confined space entry incident can easily escalate from a tragic circumstances

into a catastrophe. This can happen when the safety standby person, realizing

that someone is in difficulty, reacts by entering to carry out a rescue. One of the

hardest decisions is to not enter to save the life of a colleague, but to alert the

rescue party, assist their preparation and standby by during the rescue.

Rescuing people in a confined space has been associated with some disastrous

outcomes, including where the Master, presumably in grim determination, has

entered and succumbed, leaving a void in the overall command structure of the

ship.

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- Follow correct procedures - Stay alert and be ready to get out quickly if there are any worrying signs.

Casualty Assessment and Care

- Approach with care – don’t become a casualty too. - If the atmosphere is safe, begin primary assessment. - It the atmosphere is unsafe, remove the casualty immediately.

Methods of Casualty evacuation from an enclosed space Evacuation of casualties from enclosed spaces can be difficult and risky for both casualty and rescuers. The following methods may be adopted in an emergency evacuation.

Practice your emergency rescue procedures.

How effective is your stretcher in confined spaces? Stretchers are available that are specifically designed for use in confined spaces where rigid stretchers would not be suitable or might not even reach. Stretchers are available that roll up and can be stowed away in a backpack. Flexible stretchers and spine boards like these are ideal for use where a casualty may have to be transported through lightering holes or around other structures in tank and void space arrangements. A stretcher is the ideal means of transporting a casualty. Where the stretcher is too large, or not available, the following methods can be used :

- Forward drag (rescue crawl or neck drag) - Cross chest method - Collar pull - Leg pull - Blanket

If the atmosphere and environment are safe, and the casualty has suffered a physical injury, it is advisable to seek professional medical advice before moving him/her, particularly where it is suspected that the casualty has a spinal injury.

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Collar pull method - Employed when methods described earlier cannot be used - Casualty’s head is positioned in direction of exit.

Leg pull method

- Last resort in very enclosed spaces under life threatening situation. - If casualty’s legs are in direction of exit and casualty cannot be repositioned.

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7.0 Entering an Enclosed Space with an Unsafe Atmosphere It may sometimes be necessary to enter an enclosed space where the atmosphere cannot be made safe beforehand, or it is not possible to test the space due to the unavailability of gas detectors. Entering a space in these conditions should only be undertaken if it involves the safety of life or the safety of the ship, or due to essential operational requirements. If such a situation arises, in addition to the usual enclosed space entry precautions, further safety measures should be taken to reduce the risk of an incident. For example:

Only the minimum number of persons required to complete the work safely should enter the space.

As far as possible the space should be ventilated. Each person should wear breathing apparatus, ideally positive pressure, of the self-

contained or airline type. If the latter, airline systems with two separate air supplies (main and backup bottle) are preferable. Emergency Life Support Apparatus (ELSA) should not be used.

Personnel entering the space must be thoroughly familiar with the use of the breathing apparatus being worn.

Airline breathing apparatus should be fed with a continuous supply of air, and hoses should be laid out on deck to stop them becoming crushed or kinked. If necessary, notices should be posted instructing personnel to stand clear of the airlines. If a compressor is being used to supply the air, the duty engineer should be informed to ensure that it is not shut down inadvertently.

Should breathing difficulties be experienced or if an airline system with two separate supplies is being worn and the primary supply fails, the integrity of the air supply and airline should be checked immediately and the user should leave the space.

Each person should wear a full body rescue harness and, where practicable, be connected to a lifeline of sufficient length. The attendant situated outside the space should ensure that the lifelines run freely, paying them out and taking up the slack as necessary.

A Chief Officer collapsed when entering this hold full of logs. A seamen who attempted to rescue him also collapsed. An engineer who tried to rescue both men was lucky to escape with his life after entering the access wearing an ELSA. The Chief Officer and the seaman both lost their lives.

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Everyone entering the compartment should be provided with a personal gas detector for

measuring oxygen and, depending on the atmosphere inside the tank, flammable and toxic gas.

If residues inside the space might pose an absorption hazard to personnel, suitable protective overalls and eye protection should be worn.

If SCBA is being worn, bottle pressure readings should be taken prior to entry. Air bottle duration, whistle times and a deadline for leaving the compartment calculated in accordance with the bottle pressure readings should also be discussed and agreed.

A rescue team should stand by outside the space wearing full body rescue harnesses, breathing apparatus and lifelines, ready to enter the space immediately in case of an emergency.

7.1 Cases Analysis Heightened frequency of enclosed space incidents resulting in the death of both crewmembers and visitors Further to various Technical bulletins, the managers are concerned to note a heightened frequency of incidents resulting in the death of both crewmembers and visitors as a consequence of entry into enclosed spaces, or through the release of noxious gases in enclosed spaces. These include: 4th October 1984 Two workers (26 and 27 years old) were overcome by gas vapors and drowned after rescuing a third worker from a fracturing tank at a natural gas well. The tank contained a mixture of mud, water and natural gas. The first worker had been attempting to move a hose from the tank to another tank. A chain secured the hose and when the worker moved it, the chain fell into the tank. The worker entered the tank to retrieve the hose and was overcome. 13th may 1985 A 21-year-old worker died inside a wastewater holding tank, that was 4 feet in diameter and 8 feet deep, while attempting to clean and repair a drain line. Sulphuric acid was used to unclog a floor drain leading into the holding tank. The worker collapsed and fell face down into 6 inches of water at the bottom of the tank. A second 21-year-old worker attempted a rescue and was also overcome and collapsed. The first worker was pronounced dead at the scene and the second worker died 2 weeks later. Cause of death was attributed to asphyxiation by methane gas. Sulphuric acid vapors may have also contributed to cause of death. Spain, April 2008 The cargo receiver’s surveyor died on board after entering an untested hold via an opened access hatch. The incident occurred despite the surveyor having been strictly advised by the chief officer and another crewmember to remain out of the holds until clearance was obtained. Indonesia, June 2008 Two shore-based contractors boarded the ship with the intention of removing sludge from a tank. Unknown to the crew, they gained access to the tank. They were not using breathing apparatus, had not taken any measures to determine the composition of the atmosphere within the tank, and they were overcome by fumes and died. It is likely that one of the contractors entered the space in an attempt to rescue his colleague. USA, June 2008 A bulk carrier was discharging a coal cargo in Mobile, Alabama, when a stevedore entered the hold via an ‘Australian ladder’. The bottom of the ladder compartment was blocked by coal and it was later determined that the oxygen level was well below normal. The stevedore died. A crewmember, using only basic equipment, was lucky to escape with his own life after he had

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courageously, but recklessly, entered the area in the hope of helping the stevedore. It was later determined that the stevedore had fallen and broken his neck as a result of losing consciousness.

Fatality in Engine scavenging air receiver. A containership reported on leaving port that the second engineer was missing. After an extensive search by the crew, the individual was presumed to have gone ashore and missed the sailing. When the ship arrived at the following port the engineer was found dead behind an access door to the main propulsion engine’s scavenging air receiver. The engine’s scavenging air space can normally be accessed by two manholes located on both ends of the scavenging air receiver.

These circular manholes are secured by three L-shaped dogs, having an outer edge that is tightened against an inner circumferential lip on the edge of the access hole. Tightening is achieved by a handled fastener.

Scavenge space inspection door.

Investigators determined that the engineer entered the scavenging air receiver alone. Although his reason for entering the receiver was not known, engine maintenance was performed in that space while at the first port and he may have returned to re-inspect the area or check for left-behind tools and materials. It appears that after his entry, the door accidentally closed. Investigators believe that at that time, the upper left dog, because of its weight and perhaps the vibration of the door as it closed, caused it to move; allowing its edge to catch the lip at the opening. Once caught, the door could no longer be opened from inside the receiver. The second engineer was a mariner experienced in following company procedures and safe working practices. Unfortunately, on this occasion, he entered without informing anyone or having an assistant stationed outside. Searches by the crew in the machinery spaces and the main engine while the ship was preparing to sail, failed to uncover what had gone wrong. In this casualty, there were initially sufficient quantities of oxygen for the second engineer to breath, until the engine started, which caused the ambient conditions inside the receiver to change dramatically and kill him. Mariners may not associate certain work areas with the concept of confined spaces and therefore may fail to take the precautionary steps needed. In the engine room, the following should be considered examples of enclosed spaces: • main engine crankcases

Unplanned rescue, such as when someone instinctively rushes in to help a

downed co-worker, can easily result in a double fatality or even multiple

fatalities if there is a more than one would-be-rescuer.

Over 50% of the workers in confined spaces die while attempting to rescue

other workers.

An unplanned rescue could be the last !

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• scavenging air spaces • exhaust ducting • boiler drums • furnaces • stack casings • condensers • sewage plant tanks • fuel oil and lube oil tanks • waste oil tanks

Famous last Words ? “I just calibrated our gas monitor last month – it should still be accurate” Calibration is the cornerstone of any successful gas – monitoring program. Unless you compare and adjust your instrument to a known concentration of gas prior each use, you have no assurance of the unit’s accuracy. The workers should be using a calibrated, direct reading gas monitor. Unfortunately, they make no mention of calibration frequency. Refer to the manufacturer’s recommendations, and set up a program according to their guidelines. For your protection, and the protection of your employer, always document calibrations and preserve these records in a log. The calibration log should be maintained, current and include all the gas monitors used. These records should be on file for no less than 1 year, although retention for 5 years is advised. “I put the tubing into the space, turned on the stamping pump, waited the recommended time (for the unit to respond) and all my readings checked out OK” Monitoring the gases in one area of a confined space is a dangerous oversight. Some gases are heavier than air, some are lighter. The molecular weight of a gas determines where it will accumulate within a confined space. Air has a molecular weight of approximately 28.8. Common gases, such as hydrogen sulphide and methane, will stratify naturally at different levels. Hydrogen sulphide, for example, has a molecular weight of 34 so it can be expected to accumulate closer to the floor. Methane will be present closer to the top of the space due to its molecular weight of 16. This is assuming, of course, the space has poor natural ventilation or has not been stirred up and the gases allowed to stratify.

Atmospheres may be different in individual bays of the same tank.

“Our inerting operation looks like a success – our instrument shows 1.2% Oxygen and no LEL gases”. This common assumption can prove fatal. If you are using most common gas monitors to

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evaluate the concentration of combustible gases (LEL) in an inert environment, you may be getting a false sense of security. Gas monitors employing catalytic diffusion sensors are very effective in determining hazard potential because they operate on the fire triangle principle. When you remove one of the elements from the fire triangle, namely oxygen, no reaction takes place. The danger in this is if you have explosive amounts of gas in an inert situation and if oxygen in introduced or if the gas were to leak out of that area, a hazard could result. Members are encouraged to ensure that there is an onboard system which ensures that all shore-based personnel are aware that they must not enter an enclosed space without prior permission of the master. Rigorous enforcement of the ship’s ISPS system should ensure that the business of all visitors to the vessel is known and understood by the ship’s senior officers.

7.2 Further Considerations Suitable notices may be displayed outside all enclosed spaces designating each compartment as one where enclosed space procedures must be followed prior to entry. This may overcome the possibility of personnel regarding an enclosed space fitted with a weather-tight door as being safe, as opposed to a compartment where the only means of access is a bolted manhole. Consideration may also be given to locking the doors of spaces where access is not normally required, such as chain lockers and cofferdams. If the cargo is to be fumigated, all access doors to the cargo holds should be locked and warning notices posted prohibiting entry. These arrangements should remain in place until such time as the spaces have been fully ventilated in keeping with the fumigator’s instructions. In addition to crewmembers, shore contractors should also be required to follow a vessel’s Permit to Work procedures where applicable. No distinction should be made in this respect, and shore contractors should be fully briefed and instructed by a responsible officer in accordance with the vessel’s Permit to Work procedures before they begin. If concerns arise regarding the capabilities of the shore contractors or if it appears that they are not fulfilling the appropriate Permit to Work conditions, work should be stopped until such time as the responsible officer is satisfied that the shore contractors will work safely in compliance with the vessel’s procedures. If significant work is to be carried out concurrently in multiple enclosed spaces, for example in a shipyard or dry-dock, it may not be possible to implement the vessel’s Permit to Work system effectively and cover all work activities. Shipyards and dry-dock facilities will normally have their own procedures covering such situations and often employ their own Safety Officers or chemists to test the atmosphere of enclosed spaces, particularly if they need to comply with local regulatory requirements. However, it may be prudent to check that the procedures are satisfactory before work begins. Similarly, work should be halted if any unsafe practices are observed thereafter. In all cases it is recommended that nobody enters an enclosed space alone. Members requiring further guidance should contact the Loss Prevention department.

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Never enter an enclosed space alone or attempt to rescue somebody who has collapsed without following the vessel’s enclosed space rescue procedures.

8.0 Completion and Permit Closure On expiry of the permit-to-work, everyone should leave the space, and openings should be closed or otherwise secured against entry. At the end of the work, the permit must be closed and signed off. Where work is ongoing but the permit period expires, an extension can be provided in the form of a new permit. Where an extension is required, the safety measures originally taken must be reconfirmed and entry must be reapproved. Before closing the space, the responsible officer should check to confirm that all people and equipment have been removed. The entrance to the space should never be left unattended while open, without measures having been taken to prevent unauthorized access. This is particularly important where the access is on the deck, as there is a risk that somebody may fall in to the space.

Certain checks need to be done after tank entry

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9.0 Duties Training for attendant Any worker functioning as an attendant at a permit entry confined space must be trained in the emergency action plan, the duties of the attendant and in :

Proper use of the communications equipment used for communicating with authorized workers entering the confined space or for summoning emergency or rescue services.

Authorized procedures for summoning rescue or other emergency services. Recognition of the unusual actions of a worker which could indicate that they might be

experiencing a toxic reaction to contaminants which could be present in that space. Any training for rescuers, if the attendant will function as a rescuer. Any training for workers who enter the confined space, if the permit specifies that the

duty of the attendant will rotate among the workers authorized to enter the confined space.

Duties of the Person Authorizing or in Charge of the Entry The person who authorizes or is in charge of the permit entry confined space must comply with the following :

Make certain that all pre-entry requirements, as outlined on the permit, have been completed before any worker is allowed to enter the confined space.

Make certain that any required pre-entry conditions are present. If an in-plant rescue team is to be used in the event of an emergency, make sure that

they would be available. Make sure that any communication equipment that would be used to summon either the

in-plant rescue team or other emergency assistance is operating correctly. Terminate the entry upon becoming aware of a condition or set of conditions whose

hazard potential exceeds the limits authorized by the entry permit. Personal Responsibility If you are entering an enclosed space, it is your responsibility to :

Not enter alone Not enter without a valid tank or enclosed space entry permit Ensure that the space has been adequately ventilated, isolated emptied, or otherwise

made safe for entry. Immediately exit a space, without question, upon word from the attendant, no matter

what the reason. Follow all safety rules and procedures that apply to the job. Use the appropriate PPE.

Attendant’s Responsibilities

Maintain communications with those who have entered the space. Maintain communications with a responsible officer on the bridge. Summon assistance in an emergency. Monitor those who have entered during the job, and on entry and exit to help ensure their

safety. Monitor conditions in the space before and during entry. Control access to the enclosed space and guard against unauthorized access. Summon emergency assistance as needed. Keep records of enclosed space work, such as air test results, and a log of personnel

entry and exit times.

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Monitor factors that could affect the space and warn those entering of any changes to conditions.

The attendant should not abandon his post for any reason while personnel are in the space, unless relieved by another qualified attendant. Drills There is a statutory requirement for drills to be carried out, usually every three months (depending upon flag requirements) simulating the rescue of an incapacitated person from a dangerous space. Each drill should be recorded in the official log book. A drill should normally be held soon after significant changes of crew members. All personnel should be aware of enclosed space entry hazards and procedures.

Drills carried out on board should be as realistic as possible. It is useful to have a human-sized training dummy available so that crew can practice moving a pretend-casualty on a stretcher through a ballast tank, while wearing breathing apparatus.

Briefings should take place to ensure crew members understand the correct procedures to be followed for enclosed space entry, and the purpose of the equipment used or kept on stand-by.

Any attempt to rescue a person who has collapsed within a space should be based on a prearranged plan, which should take account of the design of the ship in question. Allocation of personnel to relieve or back-up those first into the space should be part of the plan. Regular drills should test the feasibility of the ship’s rescue plan under different and difficult circumstances. In the drill, an enclosed space should be made safe or, for operational convenience, a non-dangerous space may be used, so long as it provides equivalent, realistic conditions for actual real-life rescue. Training should include:

• Enclosed space entry procedures • Responsibilities of workers entering an enclosed space, • The hazards associated with entry into dangerous spaces, and the precautions to be

taken. • The use and maintenance of equipment and clothing required for entry into dangerous

spaces. • Hazard assessment, particularly for permit issuers. • Recognition of the circumstances and activities likely to lead to the presence of a

dangerous atmosphere. • Use of the atmosphere testing equipment. • Calibration procedures of the atmosphere testing equipment • Management of shore-side contractors.

Maintenance of equipment for entry into dangerous spaces All breathing apparatus, rescue harnesses, lifelines, resuscitation equipment and any other equipment for use in, or in connection with, entry into dangerous spaces, or for use in emergencies, should be properly maintained, inspected periodically and checked for correct operation by a competent person, and a record of the inspections and checks kept. All items of breathing apparatus should be inspected for correct operation before and after use. Equipment for testing the atmosphere of dangerous spaces, including oxygen meters, should be kept in perfect working order and, where applicable, regularly serviced and calibrated. Careful heed should be given to manufacturers’ recommendations, the details of which should always be kept with the equipment.

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Always have good lighting when in an enclosed space.

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10.0 Communication Communication between the worker inside and the standby person outside is of utmost importance. If the worker should suddenly feel distressed and not be able to summon help, an injury could quickly become a fatality. Frequently, the body positions that are assumed in a confined space make it difficult for the standby person to detect an unconscious worker. When visual monitoring of the worker is not possible because of the design of the confined space or location of the entry hatch, a voice or alarm-activated explosion-proof type of communication system will be necessary. Suitable illumination of an approved type is required to provide sufficient visibility for work. Noise in a confined space, which may not be intense enough to cause hearing damage, may still disrupt verbal communication with the emergency standby person on the exterior of the confined space. An adequate communication system will be needed and should enable communication :

Between those inside the confined space. Between those inside the confined space and those outside. To summon help in case of an emergency.

Requirements of a Confined Space Entry Communication System

Reliable. Two way continuous speech communication capability Compact, rugged, environmentally protected from water ingress Rapid deployment capability with simple, intuitive operation and minimum training

requirements. Certification covering all anticipated gases, vapors and dusts. Shift plus battery life Compatible with hand hats, gloves and breathing apparatus Operation possible with hazardous material (Hazmat) isolation suits Any cable reels taken into the entry to be compact and lightweight Roving capability for attendant to permit local mobility while monitoring transmissions Emergency alarm button on the entrants’ equipment Hand-off voice operated operation (where appropriate) Ability to operate in a high noise environment, with either headset, earpiece or telephone

handset, as necessary. Transmission discipline must be effective. The aim is to communicate any message in a logical format with good enunciation and then to smoothly hand over the communication channel. This is essential in ‘press to talk’ systems. Message confirmation should also be practiced to confirm that instructions or information have been fully understood.

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11.0 Closing Summary

11.1 Key Points when Preparing to Evaluate the Atmosphere in a Compartment

Throughout this Guidance, there has been repeated advice to stay out of confined spaces, question alternatives and devise methods of achieving the desired internal results with no human entry. However, real circumstances are more often contrary to this advice and the following should be remembered :

The effects of density layering caused by temperature inversions and water humidity-relative vapor densities can range from lightweight to much heavier height inside a space.

Turbulence caused by fans must be stopped while searching for gases, particularly when attempting to declare a fresh air gas condition. The ventilating fans should be shut down for ten minutes to allow the atmosphere to stabilize before commencing a search for any specific content.

Searching should be made in as many apertures as possible. For practical reasons, the rule to continue searching for something that may not be found is normally limited in a tank to a three level search at the top, middle and near the bottom of the space via apertures at each corner.

Even though an extended search is recommended, with three measurements as each of the four corners representing twelve tests and the corresponding time required, the tank or space design often will not facilitate this. Examples of this would be a very large tank where more test apertures would be expected, down to small and confined spaces such as a pressure vessel where only one aperture is available. The inside cargo oil tank on a VLCC is cavernous. Whatever the design, the atmosphere evaluation of the space must be carried out with a questioning and persistently calm logic, searching for any pocket of contamination that might inhaled. This is the task for a competent and reasoning person.

11.2 Evaluating the Atmosphere Secondary Locations The atmosphere evaluating analyst may have to consider chambers, ducts, double bottom tanks, pipe tunnels and other structures that do not allow gas sensing from an external location in fresh air. When a competent and responsible decision has been made that human entry into such a location is necessary, this is when breathing apparatus is required, with the associated operational precautions, unless a non-human appliance can be used to achieve the required atmosphere evaluation. Such gas testing is dealt with by the ship repair yard’s competent analyst and occasionally the shipboard competent person if circumstances demand. For safety, if breathing apparatus is used, not as a direct emergency condition but recognizing that there is no other way for the space to be declared safety for entry, it requires training, confidence and competence in use. When confined space entry cannot be avoided then a list (Enclosed Space Entry Permit form) becomes necessary (See Appendix – I). Although more items can be added to the Enclosed Space Entry Permit list, the idea is to create a firm and systematic management concept while addressing the reality. About the Ventilation, we have already describe the procedures in the chapter – 4.3 of this Guidance, although it is central the supply of fresh air. In most locations, fan driven ventilation is the norm if not a regulatory demand. It must be from a non- contaminated zone and is best delivered direct to the internal place of work, both comforting in temperature and satisfying in worker respiration. If there is an occasion when fan driven ventilation is not possible, expired human breath may accumulate a content of asphyxiating carbon dioxide, dulling the senses and becoming

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potentially lethal. The external Safety Standby person and any internal portable gas alarms sensing a reduction in oxygen are very important to prevent disaster. Special comments must be made regarding the person chosen as the Safety standby person at the entrance to a confined space. The attributes and common sense required to be proficient in this position are key to the operation. Alertness of mind, decisive direction and clear communication are essential. It is essential that this person does not become trapped by going to rescue casualties in a space and becoming an additional victim himself. In conclusion, returning to the introduction of this Guidance, it is hoped that the information included and the objective of safety on board ship will see all who consider entering dark places doing so in “FRESH AIR”

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Appendix - I

Example of Enclosed Space entry Permit

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Appendix - II

The Dangers of Hydrogen Sulphide in Marine Bunkers Source : UK Health & Safety Executive. Introduction Personnel working in the oil tanker industry are generally familiar with the hazards associated with the presence of hydrogen sulphide (H2S) in hydrocarbon products carried as cargo. However, the possibility that marine bunkers may also produce H2S gas is not always recognized so widely. Marine bunkers can contain H2S, but in varying concentrations depending on how it is manufactured. The gas itself is pungent, colorless, highly toxic and flammable. Exposure to high levels of H2S gas can be fatal and inhalation has resulted in seafarers’ lives being lost. Prior to taking bunkers, SOLAS Regulation VI/5-1 requires the vessel to be provided with a Material Safety Data Sheet (MSDS). This became mandatory on 1 January 2011. The MSDS will contain information regarding the composition of the fuel including the concentration of H2S, the effects of exposure to the gas and the first aid measures to be taken in such an event. In addition, the MSDS will often include guidance on the handling and storage of the product and exposure limits for each of its component parts. Whenever bunkers are received, there is always a risk that they may produce H2S gas. It is important to recognize that there is no direct correlation between the concentration of H2S in the bunker oil on board in a bunker tank and the amount of gas that may be generated or the speed at which it may develop. These issues cannot be predicted with accuracy as they depend on many factors including the chemical properties of the oil, temperature, viscosity, heating, storage time, agitation, tank shape and ventilation. When H2S is present in a bunker fuel, the concentration of gas inside a bunker compartment will exceed the declared H2S content of the bunkers by a significant margin as the latter is recorded as its liquid phase concentration, particularly in tanks with limited natural ventilation or within closed systems. Toxicity H2S gas is highly toxic and has a distinctive odour of rotten eggs. The smell intensifies as the gas concentration increases, and above 30 parts per million (ppm) the odour becomes sickeningly sweet. However, concentrations exceeding 100 ppm paralyze the olfactory nerves in the nose resulting in loss of smell. This characteristic makes H2S gas extremely hazardous. Breathing difficulties may be experienced above 320 ppm, and exposure to concentrations beyond this level may be lethal. A single breath of H2S gas at 1,000 ppm may result in immediate collapse and suffocation. The table on the following page details the effect on humans of different concentrations of H2S gas. Crewmembers should be made aware of the various symptoms of H2S poisoning. Many national authorities have also established long and short term exposure limits which should not be exceeded. In the United Kingdom a Workplace Exposure Limit (WEL) applies which sets a Time Weighted Average (TWA) regard-ing exposure to permitted concen-trations of H2S gas. Two time periods are specified; a long term exposure limit with an 8 hour TWA of 5 ppm, and a short term expo-sure limit with a 15 minute TWA of 10 ppm.

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Flag state requirements regarding H2S exposure limits may also apply, and checks should be made in this respect. Other Hazards Although the toxicity of H2S gas remains the primary hazard, lesser risks in the longer term may include corrosion within bunker tanks and pipelines, and damage to other system components. If the amount of H2S gas inside a tank exceeds the oxygen content, H2S may react with rust to form pyrophoric iron sulphide. Pyrophoric iron sulphide deposits may emit considerable heat when in contact with air and can be a source of ignition. As a by-product of this reaction, hydrogen and water are produced. If this contin-ues for some time and the tank atmosphere is humid, prolonged exposure to hydrogen may lead to fractures developing in the steel-work (known as hydrogen induced cracking) in areas subject to repeated tension and compression such as tank tops and floors.

Recommendations International Standards Organization (ISO) Fuel Standard ISO 8217:2010 limits the H2S content of residual and distillate marine fuels to 2 ppm (mg/kg) by weight in the liquid and not as vapour or gas concentration. Although the H2S limit does not apply until 1 July 2012, Members in the meantime may wish to stipulate ISO 8217:2010 with a maximum H2S content of 2 mg/kg when ordering bunkers in case such product is available. However, it should be borne in mind that tanks containing such bunkers may still produce H2S gas in concentrations which will be hazardous. Other recommendations include adding suitable guidance on the dangers of H2S in marine bunkers to the Safety Management System (SMS), providing vessels with a correctly calibrated H2S gas detector and personal monitors and training appropriate personnel in their use. Should it be necessary to enter a tank which has carried bunkers, it will be necessary to follow SMS procedures regarding enclosed space entry and test the atmosphere for oxygen and hydrocarbons beforehand. Safety may be further improved by carrying out a series of checks using the H2S gas detector. Since H2S is heavier than air, the tank atmosphere should be sampled at various heights to ensure that an accurate assessment of H2S gas can be made.

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Within the engine room fuel oils will be treated (purified), handled and heated to very much higher temperatures, which in turn will cause greater evolution of this gas. Notwithstanding the forced ventilation in this area, H2S being heavier than air will cause it to accumulate in the machinery space bilges and below the lower engine room plates. Under such circumstances access to these areas of the engine room should be treated in the same way as an entry into an enclosed space. If the odour of rotten eggs emerges from a tank when it is opened or if the gas detector indicates that H2S gas is present in quantities which exceed national or flag state exposure limits (typically 10 ppm), personnel should replace the tank lid immediately, evacuate the area and seek fresh air to breathe. If the smell of H2S gas is found to be coming from a bunker tank vent, the crew should be alerted immediately to this danger. All accommodation openings (doors and port-holes) should be kept closed at all times with clear notices posted in these locations as to the presence of H2S gas. Storage tanks that contain residual dirty oil should be emptied periodically to ensure there is no build up of H2S gas over time. Such tanks should also be tested regularly for the presence of H2S gas. Wherever possible, bunker storage tanks in machinery spaces that have sounding pipes that terminate within the space should be fitted with side level gauges so that the tank contents can be determined without opening the sounding pipe cap. As an additional safety measure, such sounding pipes may also be fitted with a gravity dead-weight closing device to minimize the possibly of them being left open inadvertently. Suitable notices should be posted to warn crewmembers that marine bunker tanks and residual dirty oil tanks may contain H2S gas, and of the associated symptoms and hazards.

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Appendix - III

Example of Safety Poster

ENTRY INTO ENCLOSED SPACES

GENERAL PRECAUTIONS for entry into cofferdams, ballast tanks and similar enclosed compartments of the vessel.

The atmosphere in any enclosed space may be incapable supporting human

life as that may be lack of oxygen and/or it may contain flammable or toxic gas.

Do not attempt to enter any of the vessel’s enclosed spaces unless authorized by the Master or a responsible officer and after all the appropriate safety checks have been carried out and an entry permit is

issued in line with the company requirements.

The Master or a responsible Officer must be satisfied that the space is safe

for entry by ensuring that:

A. the space is thoroughly ventilated prior to entry and that effective ventilation will be maintained continuously while the enclosed space is

occupied;

B. the atmosphere in the space is tested at different levels with suitable

and recently calibrated instruments for oxygen, hydrocarbon gas and toxic or other contaminant gases;

C. approved self-contained, positive pressure breathing apparatus and

resuscitation equipment is ready for use at the entrance to the space;

D. a rescue harness, complete with lifeline, and a fully charged safety

torch is ready for immediate use at the entrance to the space;

E. a responsible member of the crew, trained in the actions to be taken in the event of an emergency, is in constant attendance outside the space,

in the immediate vicinity of the entrance and in direct contact with a responsible officer;

F. lines of communications have been clearly established and are understood by all concerned

G. the personnel assigned to enter the space is provided with suitable

personal protective equipment which may include:

Protective work clothing or protective suits, safety boots, safety

helmet, gloves and where required safety glasses.

Safety harnesses for large spaces, or where climbing access is to be

undertaken

Approved safety torches and an approved UHF radio.

Personal gas detectors or an area gas detector and alarm.

Emergency escape breathing device(s).

REFER ALSO TO THE RELEVANT CHAPTER OF THE ISGOTT FOR MORE

DETAILED GUIDANCE ON ENTRY INTO AND WORK IN ENCLOSED SPACES.

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Example of Best Practice

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Appendix - IV

IMO REVISED RECOMMENDATIONS FOR ENTERING ENCLOSED SPACES ABOARD SHIPS

The International Maritime Organization (IMO) has published Revised Recommendations for Entering Enclosed Spaces Aboard Ships (IMO Resolution A.1050 (27)) coming into force on 01.01.2015. IMO has also agreed to introduce new requirements for enclosed space entry and rescue drills, and for the carriage of oxygen meters. IMO has been revising its guidance on enclosed space entry on board ships, to try to combat the ongoing problem of confined space incidents. The Revised Recommendations for Entering Enclosed Spaces Aboard Ships have been published as IMO Resolution A.1050(27). These replace the previous Recommendations (IMO A.864(20)). The recommendations have been expanded, and include additional guidance on training and on safety management, more examples of potential enclosed spaces, and greater emphasis on assuming spaces are unsafe to enter until proved otherwise. The main changes are as follows:

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Owners are required to take account of IMO’s revised guidelines and ensure that their Safety Management System (SMS) procedures and checklists for entering enclosed spaces are amended to reflect the new recommendations. Internal audits by the Owners of the ship’s safety management system should verify that the established procedures are complied with in practice. Comparable regulations are included in the:

HSC-Code, MODU-Code and DSC-Code

also coming into force on 01.01.2015.

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guidance on enclosed space entry & rescue

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