Working with Oxygen
Using Installing and Storing Oxygen Safely
This page provides information on the fire and explosion hazards in the use of oxygen. It is for anyone who uses oxygen gas in cylinders.
Hazards from oxygen
Oxygen gas in cylinders is used in gliding for breathing at high altitudes
The air we breathe contains about 21% oxygen. Without oxygen we would die in a matter of minutes. It may be hard to believe, but oxygen can also be dangerous. The dangers are fire and explosion.
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 grease. 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 create a dangerous situation. It becomes easier to start a fire, which will then burn hotter and more fiercely than in normal air. It may be almost impossible to put the fire out. A leaking valve or hose in a poorly ventilated room or confined space can quickly increase the oxygen concentration to a dangerous level.
The main causes of fires and explosions when using oxygen are:
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. Smoking should be forbidden where oxygen is being used.
Oxygen enrichment is often the result of:
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;
If oxygen enrichment from an oxygen leak is suspected, the oxygen supply should be turned off. Cigarettes and open flames should be extinguished. The area 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.
Some of the most serious oxygen-related 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.
Where the risk from oxygen enrichment is high, such as in a confined spacethe 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:
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:
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.
You should always: