Oxygen Enrichment Risks Fire Hazards of Oxygen and Oxygen enriched atmospheres

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Oxygen Enrichment Risks Fire Hazards of
Oxygen and Oxygen enriched atmospheres
Training PackageTP 02/05
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Oxygen Enrichment Risks
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Acknowledgement

• 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

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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

• For a fire or explosion to occur, three
  elements are required
• Combustible material,
• Oxygen and an
• Ignition source

Combustible Material
Ignition source
Oxygen
When one of the 3 elements is missing, a fire
cannot occur!
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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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Combustible materials
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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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Never use oil or grease to lubricate oxygen
equipment!

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

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

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Ignition sources
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Causes of oxygen fires

• 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

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.
• Dont 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 smoking
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Fire Hazards ofOxygen Enriched Atmospheres
Work safely ! It is your life!