Fire extinguisher types and colours: which do you need?

In the UK, all new fire extinguishers have red bodies, with a coloured band or panel showing the type. Using the wrong one can make a fire worse, so it is worth knowing them.

The types

• Water (red band). For Class A fires: wood, paper, textiles. Not for electrical fires or burning liquids, unless specifically tested for electrical use.
• Foam (cream band). For Class A and Class B fires: solids and flammable liquids such as petrol and paint.
• Dry powder (blue band). For Class A, B and C fires, including flammable gases. Powder reduces visibility and can be hazardous to breathe in enclosed spaces, so it is generally not recommended indoors.
• CO2 (black band). For Class B fires and electrical equipment. Leaves no residue, which makes it the usual choice for offices and server rooms.
• Wet chemical (yellow band). For Class F fires: cooking oil and fat in commercial kitchens.
• Water mist (white band). Suitable for several classes and some electrical fires, depending on the product.

The fire classes

• Class A: solids such as wood, paper and fabric.
• Class B: flammable liquids.
• Class C: flammable gases.
• Class D: metals.
• Class F: cooking oils and fats.
• Electrical fires are not a class of their own, because electricity is a source of ignition rather than a fuel.

How many do I need?

BS 5306-8 sets out how to select and position extinguishers. As a rule of thumb, most premises need at least two Class A extinguishers per storey, positioned on escape routes near exits, plus CO2 near electrical risks and wet chemical in commercial kitchens. Your fire risk assessment should state what is needed.

Servicing

Every extinguisher needs an annual basic service by a competent person, with an extended service every five years for water, foam and powder units, and an overhaul every ten years for CO2.