Flammable solids: Class A (US/EU/AU) Fires involving ordinary flammable
solids fall under
Class A. This includes
wood,
paper,
fabric,
rubber, and some types of
plastics. Such fires may be extinguished by water, wet chemical suppression, or dry chemical powder.
Flammable liquids: Class B (US/EU/AU) rated for flammable liquids and gases Fires involving flammable
liquids or liquefiable solids fall under
Class B. Examples may include
petrol/gasoline,
oil,
paint, some
waxes & plastics, though cooking fats and oils are explicitly excluded (discussed and categorised separately below). A solid stream of water should never be used to extinguish this type of fire because it can cause the fuel to scatter, spreading the flames. Smothering with
CO2 or foam is also effective. Halon has fallen out of favor in recent times (except for aircraft fire extinguishing systems) because it is an
ozone-depleting material (the
Montreal Protocol declares that Halon should no longer be used). Chemicals such as
FM-200 are now the recommended halogenated suppressant.
Flammable gases: Class B (US) / Class C (EU/AU) Fires involving flammable
gases fall under
Class C in the European/Australian system, and
Class B (along with flammable liquids) in the US system. This can include
natural gas,
hydrogen,
propane, and
butane. Due to the nature of the fuel, these fires can be difficult to extinguish. The most effective techniques for the control of a flammable gas fire are to stop the flow of fuel (by turning off any gas taps or valves) or to displace the supply of oxygen.
Electrical fires: Class C (US) / Class E (AU) / Unclassified (EU) in
Puerto Rico Fires involving the danger of
electrical hazards fall under
Class E under the Australian system, and
Class C under the US system. ejecting a plume of burning liquid wax into the air. Fires involving
cooking oils and
fats (greases) fall under
Class F under the European and Australian systems, and
Class K under the US system. Condensed aerosol suppression (such as Stat-X), aqueous vermiculite dispersion (AVD), F-500 encapsulator agent (F-500 EA). ==Comparison==