Each type of extinguisher may be rated for one or more classes of fire, although in some cases, an extinguisher may have limited use on a particular class of fire. They can be dangerous if used on a fire for which the extinguisher is not designed. Water, Foam, and Wet Chemical extinguishers should not be used on electrical fires.
The Classes of fire are: -
- Class A Ordinary Combustible
- Class B Flammable and Combustible liquids
- Class C Flammable Gases
- Class D Combustible metals
- Class E Electrically energised equipment
- Class F Cooking oils and fats
Portable fire extinguishers are distinguishable by their labels and their colouring. In 1997 the Standard Colours of some portable extinguishers were changed.