06/12/2021
What is a hazardous combustible gas atmosphere?
To put it simple, it’s an environment that contains combustible gasses in the atmosphere. In order for an atmosphere to be capable of burning explosively, four conditions must be met.
1. Adequate oxygen
2. Adequate fuel
3. A source of ignition
4. Sufficient molecular energy to sustain the fire chain reaction.
These four conditions are frequently diagrammed as the fire tetrahedron. If any side of the tetrahedron is missing, incomplete or insubstantial, combustion will not occur.
These can be broken down in to 4 basic groups:
Liquids - Liquids (such as petrol and other fuels) and solvents in industrial products (such as paint, ink, adhesives and cleaning fluids) give off flammable vapour which, when mixed with air, can ignite or explode.
Dusts - Dusts which can form explosive atmospheres are also classed as dangerous substances. Dusts can be produced from many everyday materials such as coal, wood, flour, grain, sugar, certain metals and synthetic organic chemicals.
Gases - Gases, such as liquefied petroleum gas (LPG) or methane, which are usually stored under pressure in cylinders and bulk containers. Uncontrolled releases can readily ignite or cause the cylinder to become a missile.
Solids - Solids include materials such as plastic foam, packaging, and textiles which can burn fiercely and give off dense black smoke, sometimes poisonous.
Other fire and explosion hazards
Many chemical substances can give rise to harmful heat and pressure effects because they are unstable or because they can react violently with other materials.
