Classification of fires: Class A will extinguish fires involving combustible solid items such as wood, plastics, paper. Class B will extinguish fires involving flammable fuels/liquids such as petrol, diesel, oil paraffin. Class C will extinguish fires involving flammable gases such as acetylene, LPG, natural gas.Dry powder will be most effective on any fire where the burning produces flame fronts as in liquids and gases. [Class B AND C-SWFEBC]. It is suggested when faced with a fire with Class C components, only extinguish if total isolation of the gas supply can take place (SWFE1-SWFE1G-SWFE2G). Dry powders are known for their “rapid flame knockdown” properties. Dry powder can also be used on electrical fires as powder is not a conductor of electricity.