The type of fire extinguisher you need will depend on the class of fire you are most likely to experience and there are 6 classes of fire:
Class A (Wood paper plastics)
Class B (Flammable & combustible liquids)
Class C (Flammable gases)
Class D (Fires involving combustible metals)
Class E (Electrically energised equipment)
Class F (Cooking oils and fats)
Water Fire Extinguishers:
The cheapest and most widely used fire extinguishers. Used for Class A fires.
Foam Fire Extinguishers:
Used for Classes A & B fires. Foam spray extinguishers are not recommended for fires involving electricity, but are safer than water if inadvertently sprayed onto live electrical apparatus.
Dry Powder Fire Extinguishers:
Often termed the ‘multi-purpose’ extinguisher, as it can be used on classes A, B & E fires.
Warning:when used indoors, powder can obscure vision or damage goods and machinery. It is also very messy.
CO2 Fire Extinguishers:
Carbon Dioxide is ideal for electrical fires, and will also extinguish class B liquid fires, but has NO POST FIRE SECURITY and the fire could re-ignite.
Wet chemical: Specialist extinguisher for class F fires.
For Metal Fires: Class D fires require specialist fire extinguisher for use on metal fires such as sodium, lithium, manganese and aluminium swarf or turnings.
New extinguishers should conform to BS EN 3, which requires that the entire body of the extinguisher be coloured red.