Dear all,
We use & store liquid O2 in our plant which comes in Oxygen tankers.What can happen if O2 leaks i mean what are hazards associated with it?Do we need any special PPEs or precaution for its arrest. What actions can be taken in such cases.If any one have some SOP or Instruction regarding the same,kindly share.
Regards,
Hansa Vyas
From India, Udaipur
198We use & store liquid O2 in our plant which comes in Oxygen tankers.What can happen if O2 leaks i mean what are hazards associated with it?Do we need any special PPEs or precaution for its arrest. What actions can be taken in such cases.If any one have some SOP or Instruction regarding the same,kindly share.
Regards,
Hansa Vyas
From India, Udaipur
This is the short answer
On top of the fire risk and explosion especially if it contact with any oil product or the risk of leak and people smoking out side or hot exhaust off vehicles
On top of being a class 2 gas and Store away from ignition sources and oxidizers. Secure with a double chain to prevent falling. Store oxygen away from flammable gases. Check connections regularly to avoid leaking.
The next thing to do is pull the MSDS sheet and read the risk problems and fire risks, plus what does your local government codes and standard state
Because oxygen is colourless, odourless and tasteless:
oxygen enrichment cannot be detected by the normal human senses!
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.
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.
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.
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.
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
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.
Smoking is Forbidden in locations liable to oxygen enrichment
BOTTOM LINE IF IT IGNITES OR CATCHES ON FIRE YOU ARE GOING TO HAVE A BLEVE (BOILING LIQUID EXPANSION VAPOUR EXPLOSION) BECAUSE THE TANK IS A COMPRESSED GAS DESIGN EVEN IF THE ESCAPE HATCHES WORK
From Canada, Calgary
On top of the fire risk and explosion especially if it contact with any oil product or the risk of leak and people smoking out side or hot exhaust off vehicles
On top of being a class 2 gas and Store away from ignition sources and oxidizers. Secure with a double chain to prevent falling. Store oxygen away from flammable gases. Check connections regularly to avoid leaking.
The next thing to do is pull the MSDS sheet and read the risk problems and fire risks, plus what does your local government codes and standard state
Because oxygen is colourless, odourless and tasteless:
oxygen enrichment cannot be detected by the normal human senses!
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.
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.
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.
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.
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
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.
Smoking is Forbidden in locations liable to oxygen enrichment
BOTTOM LINE IF IT IGNITES OR CATCHES ON FIRE YOU ARE GOING TO HAVE A BLEVE (BOILING LIQUID EXPANSION VAPOUR EXPLOSION) BECAUSE THE TANK IS A COMPRESSED GAS DESIGN EVEN IF THE ESCAPE HATCHES WORK
From Canada, Calgary
Dear Tgpenny,
Thanks a lot for gr8 explanation.Actually, few days back one liquid Oxygen carrying tank got leaked just outside our plant.
Fire hazard i was aware of but u explaned it very good.
But i am also curious to know about its heath hazard & what PPE's are required to arrest this leakage.
If u could add up to this also, it would be gr8.
Thanks & regards,
Hansa Vyas
From India, Udaipur
Thanks a lot for gr8 explanation.Actually, few days back one liquid Oxygen carrying tank got leaked just outside our plant.
Fire hazard i was aware of but u explaned it very good.
But i am also curious to know about its heath hazard & what PPE's are required to arrest this leakage.
If u could add up to this also, it would be gr8.
Thanks & regards,
Hansa Vyas
From India, Udaipur
Dear Hansa
Please go through the following from one of our earlier discussions. It's from Mr. Keshav Pillai
"As a health hazard it has been discovered that delivery of higher concentration and high pressure of O2 can cause hypoxia from pulmonary damage, as well as causing visual damage and central nervous dearrangement."
I am also not sure about any PPE requirement in such situation of O2 leakage... Lets wait for others opinion...
From India
Please go through the following from one of our earlier discussions. It's from Mr. Keshav Pillai
"As a health hazard it has been discovered that delivery of higher concentration and high pressure of O2 can cause hypoxia from pulmonary damage, as well as causing visual damage and central nervous dearrangement."
I am also not sure about any PPE requirement in such situation of O2 leakage... Lets wait for others opinion...
From India
With any gas leak Oxygen or not the following is always true in safety
DO NOT switch on or off any electrical appliances.
DO NOT smoke
DO NOT use naked flames
DO NOT use intercoms or door entry systems – they can cause sparks
DO NOT use a phone in the property – it can cause sparks.
DO NOT use mobile phones
DO NOT flick any electrical switches – they can cause sparks
DO open windows and doors to allow the gas to disperse
DO turn off gas at the meter
Oxygen gas in cylinders is used by many people at work and sometimes at home. It is used:
in welding, flame cutting and other similar pr ocesses;
for helping people with breathing difficulties;
in hyperbaric chambers as a medical tr eatment;
in decompression chambers for people who work in compr essed air or in deepsea diving;
for food preservation and packaging;
in steelworks and chemical plants.
The air we breathe contains about 21% oxygen. W ithout oxygen we would die in a matter of minutes. It may be har d to believe, but oxygen can also be danger ous. The dangers are fire and explosion.
Oxygen gas is colorless, odorless, non-toxic cryogenic liquid or colorless, odorless, oxidizing gas.
Contact with oxygen liquid, its cold vapors or cold piping can cause frostbite and cryogenic burns to exposed tissue. Liquid releases will quickly vaporize to gas.
The chief physical hazard associated with releases of the gas is its oxidizing power which can greatly accelerate the burning rate for both common and exotic combustible materials. Emergency personnel must practice extreme caution when approaching oxygen releases because of the potential for intense fire.
The primary health hazard at atmospheric pressure is respiratory system irritation after exposure to high oxygen concentrations. Maintain oxygen levels in air above 19.5% and below 23.5%. While up to 50% oxygen can be breathed for more than 24 hours without adverse effects, high concentrations in open air accelerate combustion and increase the risk of fire and explosion of combustible or flammable materials.
Effects of acute exposure
Eye contact: Can cause frostbite (liquid form).
No adverse effects from gas.
Skin contact: Can cause frostbite (liquid form).
No adverse effects from gas.
Inhalation: May cause breathing difficulty.
Prolonged exposure to high oxygen levels (>75%) can cause central nervous system depression: signs/symptoms can include headache, dizziness, drowsiness, poor coordination, slowed reaction time, slurred speech, giddiness and unconsciousness.
May cause coughing and chest pain.
May cause lung damage.
May cause soreness of the throat.
Ingestion: Not a likely route of exposure.
Effects of chronic exposure: None known.
Reproductive effects: Oxygen deficiency during pregnancy has produced developmental abnormalities in humans and experimental animals.
Skin contact: Remove contaminated clothing.
Treat for frostbite if necessary by gently warming affected areas.
Consult a physician.
Eye contact: Immediately flush eyes with plenty of water for at least 15 minutes.
Consult an ophthalmologist.
Inhalation: RESCUERS SHOULD NOT ATTEMPT TO RETRIEVE VICTIMS OF EXPOSURE TO THIS PRODUCT WITHOUT ADEQUATE PERSONAL PROTECTIVE EQUIPMENT. At a minimum, Self-Contained Breathing Apparatus should be worn.
Remove victim(s) to fresh air, as quickly as possible. If not breathing qualified personnel should administer artificial respiration. Get medical attention.
IKeep person warm and at rest.
Ingestion: No first aid should be needed.
Not considered a potential route of exposure.
Flammability: Oxidizer.
Conditions of flammability: Contact with flammable materials.
Vigorously accelerates combustion.
Extinguishing media: Use appropriate extinguishing media for surrounding fire.
Special procedures: Self-contained breathing apparatus required.
Firefighters should wear the usual protective gear.
Cool fire exposed containers with water spray.
Personnel should be evacuated, if necessary, to upwind area.
Remove containers from fire area if without risk.
Sensitivity to mechanical impact: Avoid impact against container.
Explosive power: Closed containers may rupture or explode due to pressure build-up when exposed to extreme heat.
Leak/Spill: Evacuate all non-essential personnel.
Stop leak without risk.
Keep combustible materials away from spill.
Ventilate. Eliminate all sources of ignition.
Allow to evaporate to atmosphere.
Do not walk on or roll equipment over the spill
Wear gloves and goggles
Ventilate area. Monitor the surrounding area for Oxygen level.
Handling procedures and equipment: Never allow any unprotected part of the body to touch uninsulated pipes or vessels that contain cold fluids. The extremely cold metal of the container will cause moist flesh to stick fast and tear when one attempts to withdraw from it.
Protect system components against physical damage. Check all hoses and transfer equipment before filling them with the liquid. Replace any worn or cut hoses prior to use.
Liquid Oxygen is extremely cold and is under pressure. A complete hose failure can result in a large release of Oxygen and violent movement of the hose and associated equipment, which may cause severe injury or death. Special care must be taken when depressurizing and disconnecting hoses.
Use adequate ventilation.
Avoid inhalation.
Never work on a pressurized system.
If there is a leak, close the upstream valve, blow down the system by venting to a safe place, then repair the leak.
For bulk liquid shipments
Oxygen, refrigerated liquid
UN 1073
Class 2.2 (Non-Flammable Gas) with subsidiary risk 5.1 (Oxidizer)
Oxygen behaves differently to air, compressed air, nitrogen and other inert gases. It is very reactive. Pure oxygen, at high pressure, such as from a cylinder, can react violently with common materials such as oil and gr ease. Other materials may catch fire spontaneously. Nearly all materials including textiles, rubber and even metals will burn vigorously in oxygen.
Even a small increase in the oxygen level in the air to 24% can cr eate a dangerous situation. It becomes easier to start a fir e, which will then bur n hotter and more fiercely than in normal air. It may be almost impossible to put the fir e out. A leaking valve or hose in a poorly ventilated r oom or confined space can quickly incr ease the oxygen concentration to a danger ous level.
The main causes of fires and explosions when using oxygen ar e:
❋ oxygen enrichment from leaking equipment;
use of materials not compatible with oxygen;
use of oxygen in equipment not designed for oxygen service;
incorrect or careless operation of oxygen equipment.
Risk assessment
Employers are legally required to assess the risks in the workplace, and take all reasonably practicable precautions to ensure the safety of workers and members of the public. A careful examination of the risks fr om using oxygen should be included in the risk assessment.
Beware of oxygen enrichment
Oxygen enrichment is the term often used to describe situations where the oxygen level is greater than in air. Oxygen is colourless, odourless and tasteless. The presence of an oxygen enriched atmosphere cannot be easily detected by the human senses.
The main danger to people from an oxygen enriched atmosphere is that clothing or hair can easily catch fire, causing serious or even fatal burns. For example, people can easily set their clothing and bedding on fire by smoking while receiving oxygen treatment for breathing difficulties.
Smoking should be forbidden where oxygen is being used.
Oxygen enrichment is often the result of:
leaks from damaged or poorly maintained hoses, pipes and valves;
leaks from poor connections;❋ opening valves deliberately or accidentally;
not closing valves properly after use;
using an excess of oxygen in welding, flame cutting ora similar process;
poor ventilation where oxygen is being used.
Consequently, the main ways to prevent oxygen enrichment are to keep oxygen equipment in good condition and to take care when using it. Good ventilation will also reduce the risk of oxygen enrichment.
Oxygen enrichment can also result from the misuse of oxygen. Never use oxygen for:
cooling or refreshing the air in confined spaces;
dusting benches, machinery or clothing.
If oxygen enrichment from an oxygen leak is suspected, the oxygen supply should be turned off. Cigarettes and open flames should be extinguished. The room should be well ventilated and the source of the leak identified and repaired. It is possible that oxygen may contaminate any clothing in the area. If this is suspected, the clothing should preferably be removed and taken outside for airing and ventilating.
Confined spaces
Some of the most serious oxygenrelated incidents have involved damaged oxygen hoses leaking into confined spaces, where welding and burning operations were taking place. The workers’ oxygen enriched clothing caught fire, causing serious or fatal injuries.
Gas cylinders should not be taken into confined spaces; the gas can be fed in by using hoses. The hoses should be removed from the confined space when work is finished or suspended, such as at the end of each day. Where this is not practicable, the hoses should be disconnected from the gas supply at the cylinder or manifold.
Where the risk from oxygen enrichment is high, such as in a confined space or a poorly ventilated room, the use of oxygen monitoring equipment is advisable.
Never use materials incompatible with oxygen
Some materials react explosively if they come into contact with pure oxygen at high pressure. Other materials may catch fire spontaneously. Such materials are incompatible with oxygen.
Equipment designed for oxygen service is made from materials and components that have been tested and proved to be compatible, and are safe for the purpose. The reasons for a particular design and choice of material are not always obvious. Using substitute materials or components, which appear to be similar but are not proven to be oxygen compatible, is extremely dangerous and has caused many accidents.
You need to take care when replacing:
Orings and gaskets
There are hundreds of different types of rubber and elastomer, and most are not compatible with oxygen.
Metal components
Many metals and alloys are not suitable for use with oxygen.
Never use oxygen in equipment not designed for it
Many serious accidents have been caused by using oxygen instead of other gases such as air, compressed air or nitrogen. Oxygen can react explosively with oils and greases. People have been injured or even killed when pumps, engines, tyres and pressure equipment have been blown apart by the explosion. Oxygen can also cause other materials to ignite spontaneously. The resulting fire can cause damage to equipment and injury to people.
You should never use oxygen for:
driving pneumatic tools;
inflating vehicle tyres;
pressurising and purging systems;
replacing air or inert gas;
starting diesel engines.
Oxygen must not be introduced into any equipment unless it has been designed for oxygen service by competent people with specialist knowledge.
Take care with oxygen cylinders and equipment
If oxygen cylinders and equipment are used carelessly or incorrectly, then a fire may result. All users of oxygen should know and understand the dangers, and should receive training in the use of oxygen equipment.
There are a number of precautions to follow when using oxygen equipment.
Oxygen cylinders
You should always:
handle oxygen cylinders carefully. Use a purposebuilt trolley to move them;
keep cylinders chained or clamped to prevent them from falling over;
store oxygen cylinders when not in use in a wellventilated storage area or compound, away from combustible materials and separated from cylinders of flammable gas.
Oxygen equipment
You should always:
❋ open the valve slowly. Rapid opening, particularly of cylinder valves, can result in momentarily high oxygen velocities. Any particles will be pushed through the system very quickly, causing frictional heat. Alternatively, if the system has a dead end such as where a pressure regulator is connected to an oxygen cylinder, heat can be generated through compression of the oxygen. Both cases can result in a fire;
ensure that the pressure adjusting screw of the pressure regulator is fully unwound, so that the regulator outlet valve is closed before opening the oxygen cylinder valve, particularly when opening the cylinder valve for the first time after changing cylinders;
ensure that cylinder valves are closed and piped supplies isolated whenever work is stopped. Do not try to cut off the supply of oxygen by nipping or kinking flexible hose when changing equipment, eg blowpipes;
maintain hoses and other equipment in good condition. Leak tests can be carried out easily using a proprietary spray or liquid solution that is certified for use on oxygen systems. Soap or liquids that may contain grease should not be used.
Cleanliness
You should always:
keep oxygen equipment clean. Contamination by particulate matter, dust, sand, oils, greases or general atmospheric debris is a potential fire hazard. Portable equipment is particularly susceptible to contamination, and precautions should be taken to keep it clean;
use clean hands or gloves when assembling oxygen equipment, eg attaching the pressure regulator, making connections;
wear suitable clean clothing, free from oil and easily combustible contaminants.
General precautions
You should always:
ensure that ventilation is adequate;
check that fire extinguishers are in good condition and ready for use;
check that escape routes are clear.
The Hazard Potential for Oxygen
Pure oxygen does not burn itself but makes fires burn faster and hotter. To prevent the enhanced fire situation, any location where oxygen is stored or used must be relatively free of flammable and combustible items. Examples of these materials include alcohols, solvents, petroleum products, and papers. Open flames, sparks, or high heat from smoking items, radiant heaters, and certain appliances must be controlled. The highest safe temperature for the oxygen tank and accessories is 125 degrees Fahrenheit.
Oxygen Leaks and Corrective Actions
The quantity of oxygen that might leak from a system may range from extremely low up to an emergency situation. Leaks can occur from O-rings connections, the valve packing, in blenders, or from the oxygen supply tubes used. The relative hazard rating and the appropriate action at SMH is:
Non-detectable leaks:
This type of leak is normally not detectable (no hissing sound). These leaks may be the result of a failure in the O-ring or other connections. The quantity of oxygen released into the room is less than what might be used by a patient. The general ventilation will adequately remove the excessive oxygen to prevent an enriched atmosphere of oxygen. These problems are repaired during routine maintenance activities.
The following is a great link for training cut and paste into your search engine
http://asiaiga.org <link updated to site home>
Again some Summary of advice
1 Be aware of the dangers of oxygen if in doubt, ask. ✑ 2 Prevent oxygen enrichment by ensuring that equipment is leak tight and in good working order. ✑
3 Check that ventilation is adequate. ✑
4 Always use oxygen cylinders and equipment carefully and correctly. ✑
5 Always open oxygen cylinder valves slowly. ✑
1 Do not smoke where oxygen is being used. ✕
2 Never use replacement parts which have not been specifically approved for oxygen service.
3 Never use oxygen equipment above the pressures certified by the manufacturer. ✕
4 Never use oil or grease to lubricate oxygen equipment. ✕
5 Never use oxygen in equipment which is not designed for oxygen service.
From Canada, Calgary
DO NOT switch on or off any electrical appliances.
DO NOT smoke
DO NOT use naked flames
DO NOT use intercoms or door entry systems – they can cause sparks
DO NOT use a phone in the property – it can cause sparks.
DO NOT use mobile phones
DO NOT flick any electrical switches – they can cause sparks
DO open windows and doors to allow the gas to disperse
DO turn off gas at the meter
Oxygen gas in cylinders is used by many people at work and sometimes at home. It is used:
in welding, flame cutting and other similar pr ocesses;
for helping people with breathing difficulties;
in hyperbaric chambers as a medical tr eatment;
in decompression chambers for people who work in compr essed air or in deepsea diving;
for food preservation and packaging;
in steelworks and chemical plants.
The air we breathe contains about 21% oxygen. W ithout oxygen we would die in a matter of minutes. It may be har d to believe, but oxygen can also be danger ous. The dangers are fire and explosion.
Oxygen gas is colorless, odorless, non-toxic cryogenic liquid or colorless, odorless, oxidizing gas.
Contact with oxygen liquid, its cold vapors or cold piping can cause frostbite and cryogenic burns to exposed tissue. Liquid releases will quickly vaporize to gas.
The chief physical hazard associated with releases of the gas is its oxidizing power which can greatly accelerate the burning rate for both common and exotic combustible materials. Emergency personnel must practice extreme caution when approaching oxygen releases because of the potential for intense fire.
The primary health hazard at atmospheric pressure is respiratory system irritation after exposure to high oxygen concentrations. Maintain oxygen levels in air above 19.5% and below 23.5%. While up to 50% oxygen can be breathed for more than 24 hours without adverse effects, high concentrations in open air accelerate combustion and increase the risk of fire and explosion of combustible or flammable materials.
Effects of acute exposure
Eye contact: Can cause frostbite (liquid form).
No adverse effects from gas.
Skin contact: Can cause frostbite (liquid form).
No adverse effects from gas.
Inhalation: May cause breathing difficulty.
Prolonged exposure to high oxygen levels (>75%) can cause central nervous system depression: signs/symptoms can include headache, dizziness, drowsiness, poor coordination, slowed reaction time, slurred speech, giddiness and unconsciousness.
May cause coughing and chest pain.
May cause lung damage.
May cause soreness of the throat.
Ingestion: Not a likely route of exposure.
Effects of chronic exposure: None known.
Reproductive effects: Oxygen deficiency during pregnancy has produced developmental abnormalities in humans and experimental animals.
Skin contact: Remove contaminated clothing.
Treat for frostbite if necessary by gently warming affected areas.
Consult a physician.
Eye contact: Immediately flush eyes with plenty of water for at least 15 minutes.
Consult an ophthalmologist.
Inhalation: RESCUERS SHOULD NOT ATTEMPT TO RETRIEVE VICTIMS OF EXPOSURE TO THIS PRODUCT WITHOUT ADEQUATE PERSONAL PROTECTIVE EQUIPMENT. At a minimum, Self-Contained Breathing Apparatus should be worn.
Remove victim(s) to fresh air, as quickly as possible. If not breathing qualified personnel should administer artificial respiration. Get medical attention.
IKeep person warm and at rest.
Ingestion: No first aid should be needed.
Not considered a potential route of exposure.
Flammability: Oxidizer.
Conditions of flammability: Contact with flammable materials.
Vigorously accelerates combustion.
Extinguishing media: Use appropriate extinguishing media for surrounding fire.
Special procedures: Self-contained breathing apparatus required.
Firefighters should wear the usual protective gear.
Cool fire exposed containers with water spray.
Personnel should be evacuated, if necessary, to upwind area.
Remove containers from fire area if without risk.
Sensitivity to mechanical impact: Avoid impact against container.
Explosive power: Closed containers may rupture or explode due to pressure build-up when exposed to extreme heat.
Leak/Spill: Evacuate all non-essential personnel.
Stop leak without risk.
Keep combustible materials away from spill.
Ventilate. Eliminate all sources of ignition.
Allow to evaporate to atmosphere.
Do not walk on or roll equipment over the spill
Wear gloves and goggles
Ventilate area. Monitor the surrounding area for Oxygen level.
Handling procedures and equipment: Never allow any unprotected part of the body to touch uninsulated pipes or vessels that contain cold fluids. The extremely cold metal of the container will cause moist flesh to stick fast and tear when one attempts to withdraw from it.
Protect system components against physical damage. Check all hoses and transfer equipment before filling them with the liquid. Replace any worn or cut hoses prior to use.
Liquid Oxygen is extremely cold and is under pressure. A complete hose failure can result in a large release of Oxygen and violent movement of the hose and associated equipment, which may cause severe injury or death. Special care must be taken when depressurizing and disconnecting hoses.
Use adequate ventilation.
Avoid inhalation.
Never work on a pressurized system.
If there is a leak, close the upstream valve, blow down the system by venting to a safe place, then repair the leak.
For bulk liquid shipments
Oxygen, refrigerated liquid
UN 1073
Class 2.2 (Non-Flammable Gas) with subsidiary risk 5.1 (Oxidizer)
Oxygen behaves differently to air, compressed air, nitrogen and other inert gases. It is very reactive. Pure oxygen, at high pressure, such as from a cylinder, can react violently with common materials such as oil and gr ease. Other materials may catch fire spontaneously. Nearly all materials including textiles, rubber and even metals will burn vigorously in oxygen.
Even a small increase in the oxygen level in the air to 24% can cr eate a dangerous situation. It becomes easier to start a fir e, which will then bur n hotter and more fiercely than in normal air. It may be almost impossible to put the fir e out. A leaking valve or hose in a poorly ventilated r oom or confined space can quickly incr ease the oxygen concentration to a danger ous level.
The main causes of fires and explosions when using oxygen ar e:
❋ oxygen enrichment from leaking equipment;
use of materials not compatible with oxygen;
use of oxygen in equipment not designed for oxygen service;
incorrect or careless operation of oxygen equipment.
Risk assessment
Employers are legally required to assess the risks in the workplace, and take all reasonably practicable precautions to ensure the safety of workers and members of the public. A careful examination of the risks fr om using oxygen should be included in the risk assessment.
Beware of oxygen enrichment
Oxygen enrichment is the term often used to describe situations where the oxygen level is greater than in air. Oxygen is colourless, odourless and tasteless. The presence of an oxygen enriched atmosphere cannot be easily detected by the human senses.
The main danger to people from an oxygen enriched atmosphere is that clothing or hair can easily catch fire, causing serious or even fatal burns. For example, people can easily set their clothing and bedding on fire by smoking while receiving oxygen treatment for breathing difficulties.
Smoking should be forbidden where oxygen is being used.
Oxygen enrichment is often the result of:
leaks from damaged or poorly maintained hoses, pipes and valves;
leaks from poor connections;❋ opening valves deliberately or accidentally;
not closing valves properly after use;
using an excess of oxygen in welding, flame cutting ora similar process;
poor ventilation where oxygen is being used.
Consequently, the main ways to prevent oxygen enrichment are to keep oxygen equipment in good condition and to take care when using it. Good ventilation will also reduce the risk of oxygen enrichment.
Oxygen enrichment can also result from the misuse of oxygen. Never use oxygen for:
cooling or refreshing the air in confined spaces;
dusting benches, machinery or clothing.
If oxygen enrichment from an oxygen leak is suspected, the oxygen supply should be turned off. Cigarettes and open flames should be extinguished. The room should be well ventilated and the source of the leak identified and repaired. It is possible that oxygen may contaminate any clothing in the area. If this is suspected, the clothing should preferably be removed and taken outside for airing and ventilating.
Confined spaces
Some of the most serious oxygenrelated incidents have involved damaged oxygen hoses leaking into confined spaces, where welding and burning operations were taking place. The workers’ oxygen enriched clothing caught fire, causing serious or fatal injuries.
Gas cylinders should not be taken into confined spaces; the gas can be fed in by using hoses. The hoses should be removed from the confined space when work is finished or suspended, such as at the end of each day. Where this is not practicable, the hoses should be disconnected from the gas supply at the cylinder or manifold.
Where the risk from oxygen enrichment is high, such as in a confined space or a poorly ventilated room, the use of oxygen monitoring equipment is advisable.
Never use materials incompatible with oxygen
Some materials react explosively if they come into contact with pure oxygen at high pressure. Other materials may catch fire spontaneously. Such materials are incompatible with oxygen.
Equipment designed for oxygen service is made from materials and components that have been tested and proved to be compatible, and are safe for the purpose. The reasons for a particular design and choice of material are not always obvious. Using substitute materials or components, which appear to be similar but are not proven to be oxygen compatible, is extremely dangerous and has caused many accidents.
You need to take care when replacing:
Orings and gaskets
There are hundreds of different types of rubber and elastomer, and most are not compatible with oxygen.
Metal components
Many metals and alloys are not suitable for use with oxygen.
Never use oxygen in equipment not designed for it
Many serious accidents have been caused by using oxygen instead of other gases such as air, compressed air or nitrogen. Oxygen can react explosively with oils and greases. People have been injured or even killed when pumps, engines, tyres and pressure equipment have been blown apart by the explosion. Oxygen can also cause other materials to ignite spontaneously. The resulting fire can cause damage to equipment and injury to people.
You should never use oxygen for:
driving pneumatic tools;
inflating vehicle tyres;
pressurising and purging systems;
replacing air or inert gas;
starting diesel engines.
Oxygen must not be introduced into any equipment unless it has been designed for oxygen service by competent people with specialist knowledge.
Take care with oxygen cylinders and equipment
If oxygen cylinders and equipment are used carelessly or incorrectly, then a fire may result. All users of oxygen should know and understand the dangers, and should receive training in the use of oxygen equipment.
There are a number of precautions to follow when using oxygen equipment.
Oxygen cylinders
You should always:
handle oxygen cylinders carefully. Use a purposebuilt trolley to move them;
keep cylinders chained or clamped to prevent them from falling over;
store oxygen cylinders when not in use in a wellventilated storage area or compound, away from combustible materials and separated from cylinders of flammable gas.
Oxygen equipment
You should always:
❋ open the valve slowly. Rapid opening, particularly of cylinder valves, can result in momentarily high oxygen velocities. Any particles will be pushed through the system very quickly, causing frictional heat. Alternatively, if the system has a dead end such as where a pressure regulator is connected to an oxygen cylinder, heat can be generated through compression of the oxygen. Both cases can result in a fire;
ensure that the pressure adjusting screw of the pressure regulator is fully unwound, so that the regulator outlet valve is closed before opening the oxygen cylinder valve, particularly when opening the cylinder valve for the first time after changing cylinders;
ensure that cylinder valves are closed and piped supplies isolated whenever work is stopped. Do not try to cut off the supply of oxygen by nipping or kinking flexible hose when changing equipment, eg blowpipes;
maintain hoses and other equipment in good condition. Leak tests can be carried out easily using a proprietary spray or liquid solution that is certified for use on oxygen systems. Soap or liquids that may contain grease should not be used.
Cleanliness
You should always:
keep oxygen equipment clean. Contamination by particulate matter, dust, sand, oils, greases or general atmospheric debris is a potential fire hazard. Portable equipment is particularly susceptible to contamination, and precautions should be taken to keep it clean;
use clean hands or gloves when assembling oxygen equipment, eg attaching the pressure regulator, making connections;
wear suitable clean clothing, free from oil and easily combustible contaminants.
General precautions
You should always:
ensure that ventilation is adequate;
check that fire extinguishers are in good condition and ready for use;
check that escape routes are clear.
The Hazard Potential for Oxygen
Pure oxygen does not burn itself but makes fires burn faster and hotter. To prevent the enhanced fire situation, any location where oxygen is stored or used must be relatively free of flammable and combustible items. Examples of these materials include alcohols, solvents, petroleum products, and papers. Open flames, sparks, or high heat from smoking items, radiant heaters, and certain appliances must be controlled. The highest safe temperature for the oxygen tank and accessories is 125 degrees Fahrenheit.
Oxygen Leaks and Corrective Actions
The quantity of oxygen that might leak from a system may range from extremely low up to an emergency situation. Leaks can occur from O-rings connections, the valve packing, in blenders, or from the oxygen supply tubes used. The relative hazard rating and the appropriate action at SMH is:
Non-detectable leaks:
This type of leak is normally not detectable (no hissing sound). These leaks may be the result of a failure in the O-ring or other connections. The quantity of oxygen released into the room is less than what might be used by a patient. The general ventilation will adequately remove the excessive oxygen to prevent an enriched atmosphere of oxygen. These problems are repaired during routine maintenance activities.
The following is a great link for training cut and paste into your search engine
http://asiaiga.org <link updated to site home>
Again some Summary of advice
1 Be aware of the dangers of oxygen if in doubt, ask. ✑ 2 Prevent oxygen enrichment by ensuring that equipment is leak tight and in good working order. ✑
3 Check that ventilation is adequate. ✑
4 Always use oxygen cylinders and equipment carefully and correctly. ✑
5 Always open oxygen cylinder valves slowly. ✑
1 Do not smoke where oxygen is being used. ✕
2 Never use replacement parts which have not been specifically approved for oxygen service.
3 Never use oxygen equipment above the pressures certified by the manufacturer. ✕
4 Never use oil or grease to lubricate oxygen equipment. ✕
5 Never use oxygen in equipment which is not designed for oxygen service.
From Canada, Calgary
Safety Risks on any compressed gases on your worksite
What are the three major groups of compressed gases?
There are three major groups of compressed gases stored in cylinders: liquefied, non-liquefied and dissolved gases. In each case, the pressure of the gas in the cylinder is commonly given in units of kilopascals (kPa) or pounds per square inch gauge (psig).
Gauge pressure = Total gas pressure inside cylinder - atmospheric pressure
Atmospheric pressure is normally about 101.4 kPa (14.7 psi). Note that compressed gas cylinder with a pressure gauge reading of 0 kPa or 0 psig is not really empty. It still contains gas at atmospheric pressure.
Liquefied Gases
Liquefied gases are gases which can become liquids at normal temperatures when they are inside cylinders under pressure. They exist inside the cylinder in a liquid-vapour balance or equilibrium. Initially the cylinder is almost full of liquid, and gas fills the space above the liquid. As gas is removed from the cylinder, enough liquid evaporates to replace it, keeping the pressure in the cylinder constant. Anhydrous ammonia, chlorine, propane, nitrous oxide and carbon dioxide are examples of liquefied gases.
Non-Liquefied Gases
Non-liquefied gases are also known as compressed, pressurized or permanent gases. These gases do not become liquid when they are compressed at normal temperatures, even at very high pressures. Common examples of these are oxygen, nitrogen, helium and argon.
Dissolved Gases
Acetylene is the only common dissolved gas. Acetylene is chemically very unstable. Even at atmospheric pressure, acetylene gas can explode. Nevertheless, acetylene is routinely stored and used safely in cylinders at high pressures (up to 250 psig at 21?C).
This is possible because acetylene cylinders are fully packed with an inert, porous filler. The filler is saturated with acetone or other suitable solvent. When acetylene gas is added to the cylinder, the gas dissolves in the acetone. Acetylene in solution is stable.
What are the pressure hazards associated with compressed gas cylinders?
All compressed gases are hazardous because of the high pressures inside the cylinders. Gas can be released deliberately by opening the cylinder valve, or accidentally from a broken or leaking valve or from a safety device. Even at a relatively low pressure, gas can flow rapidly from an open or leaking cylinder.
There have been many cases in which damaged cylinders have become uncontrolled rockets or pinwheels and have caused severe injury and damage. This danger has happened when unsecured, uncapped cylinders were knocked over causing the cylinder valve to break and high pressure gas to escape rapidly. Most cylinder valves are designed to break at a point with an opening of about 0.75 cm (0.3 inches). This design limits the rate of gas release and reduces cylinder velocity. This limit may prevent larger, heavier cylinders from "rocketing" although smaller or lighter cylinders might take off.
Poorly controlled release of compressed gas in chemical reaction systems can cause vessels to burst, create leaks in equipment or hoses, or produce runaway reactions.
What are the fire and explosion hazards associated with compressed gases?
Flammable Gases
Flammable gases, such as acetylene, butane, ethylene, hydrogen, methylamine and vinyl chloride, can burn or explode under certain conditions:
Gas Concentration within the Flammable Range: The concentration of the gas in air (or in contact with an oxidizing gas) must be between its lower flammable limit (LFL) and upper flammable limit (UFL) [sometimes called the lower and upper explosive limits (LEL and UEL)]. For example, the LFL of hydrogen gas in air is 4 percent and its UFL is 75 percent (at atmospheric pressure and temperature). This means that hydrogen can be ignited when its concentration in the air is between 4 and 75 percent. A concentration of hydrogen below 4 percent is too "lean" to burn. Hydrogen gas levels above 75 percent are too "rich" to burn.
The flammable range of a gas includes all of its concentrations in air between the LFL and UFL. The flammable range of any gas is widened in the presence of oxidizing gases such as oxygen or chlorine and by higher temperatures or pressures. For example, the flammable range of hydrogen in oxygen gas is 4 to 85 percent and the flammable range of hydrogen in chlorine gas is 4.1 to 89 percent.
Ignition Source: For a flammable gas within its flammable limits in air (or oxidizing gas) to ignite, an ignition source must be present. There are many possible ignition sources in most workplaces including open flames, sparks and hot surfaces.
The auto-ignition (or ignition) temperature of a gas is the minimum temperature at which the gas self-ignites without any obvious ignition sources. Some gases have very low auto-ignition temperatures. For example, phosphine's auto-ignition temperature of 100?C (212?F) is low enough that it could be ignited by a steam pipe or a lit light bulb. Some compressed gases, such as silane and diborane, are pyrophoric - they can ignite spontaneously in air.
Flash-back can occur with flammable gases. Many flammable compressed gases are heavier than air. If a cylinder leaks in a poorly ventilated area, these gases can settle and collect in sewers, pits, trenches, basements or other low areas. The gas trail can spread far from the cylinder. If the gas trail contacts an ignition source, the fire produced can flash back to the cylinder.
Oxidizing Gases
Oxidizing gases include any gases containing oxygen at higher than atmospheric concentrations (above 23-25 percent), nitrogen oxides, and halogen gases such as chlorine and fluorine. These gases can react rapidly and violently with combustible materials such as the following:
organic (carbon-containing) substances such as most flammable gases, flammable and combustible liquids, oils, greases, many plastics and fabrics
finely-divided metals
other oxidizable substances such as hydrazine, hydrogen, hydrides, sulphur or sulphur compounds, silicon and ammonia or ammonia compounds.
Fires or explosions can result.
The normal oxygen content in air is 21 percent. At slightly higher oxygen concentrations, for example 25 percent, combustible materials, including clothing fabrics, ignite more easily and burn much faster. Fires in atmospheres enriched with oxidizing gases are very hard to extinguish and can spread rapidly.
Dangerously Reactive Gases
Some pure compressed gases are chemically unstable. If exposed to slight temperature or pressure increases, or mechanical shock, they can readily undergo certain types of chemical reactions such as polymerization or decomposition. These reactions may become violent, resulting in fire or explosion. Some dangerously reactive gases have other chemicals, called inhibitors, added to prevent these hazardous reactions.
Common dangerously reactive gases are acetylene, 1,3-butadiene, methyl acetylene, vinyl chloride, tetrafluoroethylene and vinyl fluoride.
What are the health hazards associated with compressed gases?
Many compressed gases are toxic or very toxic. They could cause various health problems depending on the specific gas, its concentration, the length of exposure and the route of exposure (inhalation, eye or skin contact). Contact between the skin or eye and liquefied gases in liquid form can freeze the tissue and result in a burn-like injury.
What is the danger of an inert gas?
Inert gases, such as argon, helium, neon and nitrogen, are not toxic and do not burn or explode. Yet they can cause injury or death if they are present in sufficiently high concentrations. They can displace enough air to reduce oxygen levels. If oxygen levels are low enough, people entering the area can lose consciousness or die from asphyxiation. Low oxygen levels can particularly be a problem in poorly ventilated, confined spaces.
From Canada, Calgary
What are the three major groups of compressed gases?
There are three major groups of compressed gases stored in cylinders: liquefied, non-liquefied and dissolved gases. In each case, the pressure of the gas in the cylinder is commonly given in units of kilopascals (kPa) or pounds per square inch gauge (psig).
Gauge pressure = Total gas pressure inside cylinder - atmospheric pressure
Atmospheric pressure is normally about 101.4 kPa (14.7 psi). Note that compressed gas cylinder with a pressure gauge reading of 0 kPa or 0 psig is not really empty. It still contains gas at atmospheric pressure.
Liquefied Gases
Liquefied gases are gases which can become liquids at normal temperatures when they are inside cylinders under pressure. They exist inside the cylinder in a liquid-vapour balance or equilibrium. Initially the cylinder is almost full of liquid, and gas fills the space above the liquid. As gas is removed from the cylinder, enough liquid evaporates to replace it, keeping the pressure in the cylinder constant. Anhydrous ammonia, chlorine, propane, nitrous oxide and carbon dioxide are examples of liquefied gases.
Non-Liquefied Gases
Non-liquefied gases are also known as compressed, pressurized or permanent gases. These gases do not become liquid when they are compressed at normal temperatures, even at very high pressures. Common examples of these are oxygen, nitrogen, helium and argon.
Dissolved Gases
Acetylene is the only common dissolved gas. Acetylene is chemically very unstable. Even at atmospheric pressure, acetylene gas can explode. Nevertheless, acetylene is routinely stored and used safely in cylinders at high pressures (up to 250 psig at 21?C).
This is possible because acetylene cylinders are fully packed with an inert, porous filler. The filler is saturated with acetone or other suitable solvent. When acetylene gas is added to the cylinder, the gas dissolves in the acetone. Acetylene in solution is stable.
What are the pressure hazards associated with compressed gas cylinders?
All compressed gases are hazardous because of the high pressures inside the cylinders. Gas can be released deliberately by opening the cylinder valve, or accidentally from a broken or leaking valve or from a safety device. Even at a relatively low pressure, gas can flow rapidly from an open or leaking cylinder.
There have been many cases in which damaged cylinders have become uncontrolled rockets or pinwheels and have caused severe injury and damage. This danger has happened when unsecured, uncapped cylinders were knocked over causing the cylinder valve to break and high pressure gas to escape rapidly. Most cylinder valves are designed to break at a point with an opening of about 0.75 cm (0.3 inches). This design limits the rate of gas release and reduces cylinder velocity. This limit may prevent larger, heavier cylinders from "rocketing" although smaller or lighter cylinders might take off.
Poorly controlled release of compressed gas in chemical reaction systems can cause vessels to burst, create leaks in equipment or hoses, or produce runaway reactions.
What are the fire and explosion hazards associated with compressed gases?
Flammable Gases
Flammable gases, such as acetylene, butane, ethylene, hydrogen, methylamine and vinyl chloride, can burn or explode under certain conditions:
Gas Concentration within the Flammable Range: The concentration of the gas in air (or in contact with an oxidizing gas) must be between its lower flammable limit (LFL) and upper flammable limit (UFL) [sometimes called the lower and upper explosive limits (LEL and UEL)]. For example, the LFL of hydrogen gas in air is 4 percent and its UFL is 75 percent (at atmospheric pressure and temperature). This means that hydrogen can be ignited when its concentration in the air is between 4 and 75 percent. A concentration of hydrogen below 4 percent is too "lean" to burn. Hydrogen gas levels above 75 percent are too "rich" to burn.
The flammable range of a gas includes all of its concentrations in air between the LFL and UFL. The flammable range of any gas is widened in the presence of oxidizing gases such as oxygen or chlorine and by higher temperatures or pressures. For example, the flammable range of hydrogen in oxygen gas is 4 to 85 percent and the flammable range of hydrogen in chlorine gas is 4.1 to 89 percent.
Ignition Source: For a flammable gas within its flammable limits in air (or oxidizing gas) to ignite, an ignition source must be present. There are many possible ignition sources in most workplaces including open flames, sparks and hot surfaces.
The auto-ignition (or ignition) temperature of a gas is the minimum temperature at which the gas self-ignites without any obvious ignition sources. Some gases have very low auto-ignition temperatures. For example, phosphine's auto-ignition temperature of 100?C (212?F) is low enough that it could be ignited by a steam pipe or a lit light bulb. Some compressed gases, such as silane and diborane, are pyrophoric - they can ignite spontaneously in air.
Flash-back can occur with flammable gases. Many flammable compressed gases are heavier than air. If a cylinder leaks in a poorly ventilated area, these gases can settle and collect in sewers, pits, trenches, basements or other low areas. The gas trail can spread far from the cylinder. If the gas trail contacts an ignition source, the fire produced can flash back to the cylinder.
Oxidizing Gases
Oxidizing gases include any gases containing oxygen at higher than atmospheric concentrations (above 23-25 percent), nitrogen oxides, and halogen gases such as chlorine and fluorine. These gases can react rapidly and violently with combustible materials such as the following:
organic (carbon-containing) substances such as most flammable gases, flammable and combustible liquids, oils, greases, many plastics and fabrics
finely-divided metals
other oxidizable substances such as hydrazine, hydrogen, hydrides, sulphur or sulphur compounds, silicon and ammonia or ammonia compounds.
Fires or explosions can result.
The normal oxygen content in air is 21 percent. At slightly higher oxygen concentrations, for example 25 percent, combustible materials, including clothing fabrics, ignite more easily and burn much faster. Fires in atmospheres enriched with oxidizing gases are very hard to extinguish and can spread rapidly.
Dangerously Reactive Gases
Some pure compressed gases are chemically unstable. If exposed to slight temperature or pressure increases, or mechanical shock, they can readily undergo certain types of chemical reactions such as polymerization or decomposition. These reactions may become violent, resulting in fire or explosion. Some dangerously reactive gases have other chemicals, called inhibitors, added to prevent these hazardous reactions.
Common dangerously reactive gases are acetylene, 1,3-butadiene, methyl acetylene, vinyl chloride, tetrafluoroethylene and vinyl fluoride.
What are the health hazards associated with compressed gases?
Many compressed gases are toxic or very toxic. They could cause various health problems depending on the specific gas, its concentration, the length of exposure and the route of exposure (inhalation, eye or skin contact). Contact between the skin or eye and liquefied gases in liquid form can freeze the tissue and result in a burn-like injury.
What is the danger of an inert gas?
Inert gases, such as argon, helium, neon and nitrogen, are not toxic and do not burn or explode. Yet they can cause injury or death if they are present in sufficiently high concentrations. They can displace enough air to reduce oxygen levels. If oxygen levels are low enough, people entering the area can lose consciousness or die from asphyxiation. Low oxygen levels can particularly be a problem in poorly ventilated, confined spaces.
From Canada, Calgary
Community Support and Knowledge-base on business, career and organisational prospects and issues - Register and Log In to CiteHR and post your query, download formats and be part of a fostered community of professionals.