Flammable Gases

Acetylene, Hydrogen, Propane, Propylene and Methane are all flammable gases referred to as fuel gases. When these gases are mixed with an oxidant and provided with an ignition source they will burn.

The fuel gases all have an associated asphyxiation hazard but also present the more important hazards of fire and explosion.

The diagram below shows the flammability concentration limits for an atmosphere of air. The orange bands show the percentage range of fuel gas that present particular danger of fire and explosion

flammability concentration limits for an atmosphere of air

As the percentage of the fuel gas increases, the risk of fire becomes greater. After the concentration has exceeded the upper value, the air becomes saturated by the gas and ignition becomes less likely.

Any container that is kept inside or in a confined space can mean that even small quantities of escaping fuel gas are sufficient under certain conditions to form an ignitable mixture. There is only a small risk that the lower ignition limits will be reached in large working areas that have good natural ventilation or are in the open air.

Leakage of fuel gases may form ignitable mixtures with the surrounding air and lead to fire or explosions. For this reason many of them are ‘stenched’ (given a smell, e.g. rotting fish) which means that leaks can be more readily identified.

For further information on flammable gases please contact us on 0800 111 333