• Meaning and relevance of flash point, fire point and ignition point (kindling point), auto-ignition temperature, vapour density, vapour pressure, flammable liquid categories, upper flammable limit, and lower flammable limit. • The conditions required to cause the ignition of combustible solids, flammable liquids, and gaseous materials.
E2.3 Explosion and explosive combustion Assessment criteria E2.1-E2.3: Describe the principles of combustion in relation to fire safety. Common materials involved in explosions (flammable vapours, gases, dusts) Explosive atmospheres can be caused by flammable gases, mists, vapours or by combustible dust. A sufficient amount of the substance when mixed with air will, if ignited, cause an explosion. Flammable vapours can be released from liquids such as petrol, solvents, paints, and adhesives which if mixed with air can easily ignite or explode. Gases such as hydrogen, propane, acetylene, methane, or LPG are mainly stored under pressure in cylinders or bulk containers. An uncontrolled release can ignite the gas or cause the cylinder to become a missile. Examples of dust that may become explosive and are classed as dangerous substances include dust from coal, wood, flour, sugar, polythene, grain, and certain metals. They can be found in everyday materials or from raw materials, intermediates, finished or waste products. Combustible dust in the air can explode violently if it has been ignited, such as from a spark or naked flame.
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