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Fire Hazards of Oxygen and Oxygen enriched atmospheres

Training PackageTP 02/05

Oxygen Enrichment RisksOxygen Enrichment Risks

Asia Industrial Gases Association

298 Tiong Bahru Road, #20-01 Central Plaza, Singapore 168730

Internet: http//www.asiaiga.org

AIGA 2005 - AIGA grants permission to reproduce this publication provided the Association is acknowledged as the source

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Oxygen Enrichment RisksOxygen Enrichment Risks

Disclaimer

All publications of AIGA or bearing AIGA’s name contain information, including Codes of Practice, safety procedures and other technical information that were obtained from sources believed by AIGA to be reliable and/ or based on technical information and experience currently available from members of AIGA and others at the date of the publication. As such, we do not make any representation or warranty nor accept any liability as to the accuracy, completeness or correctness of the information contained in these publications.

While AIGA recommends that its members refer to or use its publications, such reference to or use thereof by its members or third parties is purely voluntary and not binding.

AIGA or its members make no guarantee of the results and assume no liability or responsibility in connection with the reference to or use of information or suggestions contained in AIGA’s publications.

AIGA has no control whatsoever as regards, performance or non performance, misinterpretation, proper or improper use of any information or suggestions contained in AIGA’s publications by any person or entity (including AIGA members) and AIGA expressly disclaims any liability in connection thereto.

AIGA’s publications are subject to periodic review and users are cautioned to obtain the latest edition.

Asia Industrial Gases Association

298 Tiong Bahru Road, #20-01 Central Plaza, Singapore 168730

Internet: http//www.asiaiga.org

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This document is adopted from the European Industrial Gases Association document TP 12/05

and acknowledgement and thanks are hereby

given to EIGA for permission granted for the use

of their document.

AcknowledgementAcknowledgement

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Properties of oxygenOxygen supports life

                                                                         

Oxygen is essential to life

• Its normal concentration in the air we breathe is approximately 21 %

• We can breathe in a 50-60% oxygen enriched atmosphere for several hours under medical care (oxygen therapy) But it is dangerous to do so without knowing the associated risks due to oxygen enrichment !

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Properties of oxygenOxygen supports combustion

It is not flammable but supports combustion.Most materials burn fiercely sometimes explosively in oxygen. As the oxygen concentration in air increases, the potential fire risk increases.

At concentrations above 23 % in air, the situation becomes dangerous due to the increased fire hazard. This was a van which caught fire very quickly, due to driver

who smoked inside while transporting oxygen (oxygen enriched atmosphere).

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Properties of oxygenOxygen gives no warning

Because oxygen is colourless, odourless and tasteless:

oxygen enrichment cannot be detected by the normal

human senses!

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Properties of oxygenOxygen is heavier than air

Being heavier than air, oxygen can accumulate in low lying areas

such as trenches, pits,or underground rooms,

especially in cases of cryogenic liquid spillage.

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Necessary conditions for a fire

When one of the 3 elements is missing, a fire cannot occur!

OxygenC

ombu

stib

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Mat

eria

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Ignition sourceFor a fire or explosion to occur, three elements are required:

Combustible material,Oxygen and an Ignition source

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Oxygen…

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A leaking equipment is very dangerous

Leaks can lead to oxygen enrichment, i.e. increased fire hazard.

Leaking connections, flanges and fittings connected to an oxygen source are hazardous causing the oxygen concentration in the surrounding to increase.

Insufficient ventilation increases the risk.

All equipment, newly assembled or after maintenance, has to be thoroughly leak tested before going into service.

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Liquid Oxygen spill

• A spill of liquid oxygen creates a dense cloud of oxygen enriched air as it vaporises.

• The clothing of personnel entering the cloud will become enriched with oxygen.

• When liquid oxygen impregnates the soil which contains organic material, e.g. wood, asphalt, etc., a dangerous situation exists, as the organic material is liable to explode when impacted.

• Liquid oxygen filling locations are areas where oxygen enrichment is likely to occur.

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Combustiblematerials…

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Compatibility of materials

• Only certain materials are suitable for use in oxygen service.

• Most materials - including

metals!- will burn in pure oxygen or in oxygen enriched atmospheres, even if they cannot be ignited in air.

• Oils, grease and materials contaminated with these substances are particularly hazardous in the presence of an oxygen enriched atmosphere, as they can ignite extremely easily and burn with explosive violence.

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• Equipment contaminated with oil and grease shall be cleaned for oxygen using approved cleaning agents/methods.

Never use oil or grease to lubricate oxygen equipment!

• Check with your supervisor that any material/part or substance you intend to use is approved for oxygen service.

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Ignitionsources…

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• Oxygen Enrichment of the atmosphere, for example during cryogenic liquid filling

• Shock impact with combustible material

• Improper use of oxygen

• Incorrect operation and maintenance of oxygen systems

• Use materials non compatible with oxygen service

Causes of oxygen fires

Above oxygen tanker exploded due to the ignition of the asphalt coating of the road which was impregnated with oxygen.

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Do not use oxygen for applications for which it is not

intended!

Do not use oxygen as a substitute for air, example:

• operating pneumatic tools • inflating tyres • starting diesel engines • dusting benches, machinery or clothing

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No flame in oxygen enriched atmospheres

• Oxygen enriched atmosphere can occur at:

– Pits, trenches,– Low enclosed areas, underground ways– Sewers– In ASUs, cylinder filling plants,…– Around tanker filling– Around vents, leaks– …

• In such areas :– DO NOT SMOKE– Do not use naked flames, do not weld– Wear adequate fire-resistant or cotton

garments and underclothing.

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No work before checking atmosphere • If hot work (welding, flame cutting, soldering, grinding, etc.) has to be

carried out, ensure that:– the atmosphere has been checked and confirmed as safe – If not, use ventilation means.

• Don’t start work without a Permit to Work

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If exposed to an oxygen enriched atmosphere

If you have been exposed to an oxygen enriched atmosphere or if you exit a location liable to oxygen enrichment:

Ventilate your clothing in the open air

for at least 15 minutes before smoking or going near a source of ignition.

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Do you work in locations liable to oxygen enrichment?

Smoking is Forbidden in

locations liable to oxygen enrichment

No smokin

g

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Fire Hazards ofFire Hazards ofOxygen Enriched AtmospheresOxygen Enriched Atmospheres

Work safely !It is your life!