Fire Extinguisher Types — Which One for Which Fire? (UK Guide 2026)

The five UK fire classes

UK fire classes are defined in BS EN 2:

• Class A — Solid combustibles (paper, wood, textiles)
• Class B — Flammable liquids (petrol, oils, solvents)
• Class C — Flammable gases (LPG, methane)
• Class D — Combustible metals (sodium, magnesium, titanium)
• Class F — Cooking oils and fats (kitchen frying media)

A sixth informal category covers electrical fires — electricity is a source, not a class.

The colour code system

UK extinguishers are all red bodies with a coloured label or band identifying the agent:

| Agent | Band colour | Suitable for | |---|---|---| | Water | Red | Class A only | | Foam (AFFF) | Cream | Class A, B | | CO₂ | Black | Class B, electrical | | ABC Powder | Blue | Class A, B, C, electrical | | Wet Chemical | Yellow | Class A, F | | Water Mist | White & red | Class A, B, C, F, electrical |

The red body is required under BS EN 3 — older European colour-coded bodies are no longer compliant.

Selection by environment

Office: AFFF foam (covers paper fires and small flammable-liquid spills) + CO₂ (for electrical and copier areas).

Restaurant kitchen: Wet chemical at every cooking station (Class F) + CO₂ for electrical + AFFF in dining areas.

Server room / IT space: CO₂ (electrical) — never water or powder.

Industrial / warehouse: ABC powder broad-spectrum, plus targeted CO₂ for plant.

Vehicle / forecourt: ABC powder.

Care home / hospital: Water mist increasingly popular — works on all classes including electrical, no toxicity.

Common errors

Mistakes we find regularly on site:

• Foam extinguisher next to a deep-fat fryer — useless against Class F; can spread burning oil
• Water extinguisher near electrical equipment — significant electrocution risk
• CO₂ in a small room — asphyxiation risk if used without ventilation
• Powder in enclosed offices — clean-up cost can exceed the fire damage
• No extinguisher within 30m travel distance — breach of BS 5306-8

How many do you need?

BS 5306-8 calculates extinguisher provision based on floor area and fire class. As a rough baseline:

• 2 x 13A (water or foam) per floor for Class A risks
• Travel distance to nearest extinguisher: maximum 30 metres
• 1 x CO₂ within 10m of any electrical hazard
• 1 x wet chemical per cooking station

Servicing requirements

Under BS 5306-3:

• Monthly visual user checks (Responsible Person)
• Annual basic service (competent contractor)
• 5-year extended service (powder, foam, water)
• 10-year overhaul (CO₂)
• Disposal under Hazardous Waste Regulations

MetroFire delivers BS 5306-8 site surveys, BS 5306-3 servicing and BAFE SP101-aligned competent technicians. Book a service.