Fire Extinguisher Colours and Types: A UK Guide

Picking the wrong extinguisher can make a fire worse, and in a real emergency nobody has time to read the small print. Fire extinguisher colours are there so people can grab the right one quickly. This guide explains every UK extinguisher colour, which fires each type works on, what never to use it on, and how to read the rating on the label.

Fire extinguisher colours chart (UK)

The body of a modern UK extinguisher is signal red. The agent inside is shown by a colour zone, which London Fire Brigade guidance says can cover up to 5% of the surface area.

Source: London Fire Brigade Guidance Note 08 (Rev 20, January 2025); Warwickshire Fire and Rescue Service; HM Government, Fire safety risk assessment: offices and shops. Always follow the instructions on the extinguisher label.

Why are all fire extinguishers red?

A single red body makes every extinguisher easy to spot as firefighting equipment, wherever it is mounted. London Fire Brigade guidance states that the body should be signal red whatever the extinguishing agent, with a colour zone to identify the contents.

So when people talk about a “blue” or “black” extinguisher, they mean a red extinguisher with a blue or black band or label panel. Older extinguishers made to previous standards were often painted entirely in the colour of their agent. Government guidance says these remain acceptable until they are no longer serviceable, but it is good practice not to mix old and new styles on the same floor. Water mist units are an exception to the red rule: London Fire Brigade describes them as having a white body.

The types of fire extinguisher explained

Red: water extinguishers

Water extinguishers are for Class A fires involving solid materials such as wood, paper, cardboard and textiles. The water soaks into the material and cools it below the point where it will keep burning.

Water conducts electricity, so it must not be used on live electrical equipment. Plain water must never be used on burning liquids or cooking oil either, because it can spread the fire. Plain water units are large and heavy. Versions with additives have a higher firefighting rating, so a smaller extinguisher can do the same job.

Typical locations: offices, shops, schools, warehouses and corridors where paper, packaging and furniture are the main fuel.

Cream: foam extinguishers

Foam extinguishers work on Class A solids and Class B flammable liquids. The foam forms a blanket over the burning surface that seals in flammable vapours and starves the fire of oxygen, while the water content cools it.

Do not use foam on live electrical equipment or metal fires. Many workplaces are replacing older AFFF foam because of restrictions on PFAS chemicals. London Fire Brigade notes that fluorine-free foam is the more environmentally friendly option. Our guide to the AFFF fire extinguisher ban explains what has changed and what duty-holders need to do.

Typical locations: premises with both general combustibles and flammable liquids, such as garages, workshops and some warehouses.

Blue: dry powder extinguishers

Standard “ABC” dry powder extinguishers work on Class A, B and C fires, and government guidance says they give a good knock down. They can be used on electrical equipment, but will almost certainly leave it useless.

Powder has drawbacks indoors. It does not soak in or cool well, so a fire can reignite. Warwickshire Fire and Rescue Service advises avoiding breathing in the powder and notes that clean-up afterwards is difficult. Government guidance adds that powder can cut visibility, may affect people with breathing problems and is not generally suitable for enclosed spaces.

Specialist Class D powder for metal fires is a different product with a violet code. Standard ABC powder should not be used on metal fires.

Typical locations: vehicles, forecourts, boiler rooms, outdoor and mixed-risk areas, and sites with flammable gas.

Black: carbon dioxide (CO2) extinguishers

CO2 extinguishers are for Class B flammable liquid fires and for electrical equipment, including computers and switchgear. The gas displaces the oxygen around the fire.

CO2 does little to cool, so once the gas disperses a fire can reignite if the material is still hot. That is why CO2 is not listed for Class A fires. A 2.5 kg CO2 extinguisher is typically rated 34B.

Typical locations: offices, server rooms, plant rooms and anywhere with significant electrical equipment.

Yellow: wet chemical extinguishers

Wet chemical extinguishers are designed for Class F fires involving cooking oils and fats, such as deep fat fryers in commercial kitchens. The agent bonds with the burning fat or oil, smothering the fire and cooling it.

Government fire safety guidance describes Class F extinguishers as particularly suitable for commercial catering premises with deep-fat fryers, and says foam extinguishers are not suitable for deep-fat fryers or chip pans. Essex County Fire and Rescue Service warns never to throw water on hot or burning oil. A light-duty fire blanket is an alternative for a small pan fire.

Typical locations: commercial kitchens, canteens and food production areas with fryers.

White: water mist extinguishers

Water mist extinguishers spray very fine water droplets. London Fire Brigade lists them as suitable for Class A, B and C fires and for electrical fires. The mist cools the fire and creates a barrier between the flames and the person using it.

Because one water mist unit covers several classes, it can reduce the number of different extinguisher types staff need to recognise. Check the label for any voltage or distance limits on electrical use.

Green: clean agent and lithium-ion extinguishers

Green is used for clean agent extinguishers. London Fire Brigade guidance says green-coded lithium-ion extinguishers can be used on small lithium-ion battery fires, are suitable for Class A fires, and use clean agent gases or wet chemical solutions to limit damage to sensitive equipment.

Halon extinguishers also used green, but government guidance notes that no new halon production is permitted in the UK. If you find an old halon unit, ask a competent fire equipment engineer to deal with it.

If a battery pack in an e-bike, scooter or power tool catches fire, raise the alarm and evacuate unless the fire is very small and you have the right equipment and training.

Which fire extinguisher should you use?

Match the extinguisher to what is burning. Use this as a quick guide, and see our full guide to the classes of fire for more detail.

1. Paper, wood, fabric or general rubbish: water (red), foam (cream), water mist (white) or dry powder (blue).
2. Petrol, diesel, oils, solvents or paint: foam (cream), CO2 (black), dry powder (blue) or water mist (white). Never water.
3. Flammable gas: shut off the supply if it is safe to do so. Dry powder (blue) on specialist advice.
4. Burning metal: Class D powder (violet) or dry sand only, on specialist advice.
5. Live electrical equipment: CO2 (black), dry powder (blue) or water mist (white). Isolate the power if safe.
6. Cooking oil or fat: wet chemical (yellow) or a fire blanket. Never water.

Only tackle a fire if it is small, you are trained, you have the right extinguisher and your escape route is clear behind you. London Fire Brigade is clear that extinguishers are for small, contained fires, and that evacuation comes first. Our guide to the fire triangle explains how each agent puts a fire out.

What do the numbers on a fire extinguisher mean?

The rating on the label shows which classes of fire the extinguisher has been tested on and how much fire it can put out. The letter is the class of fire, and the number relates to the size of test fire it put out under BS EN 3-7, so a higher number means more firefighting capacity.

London Fire Brigade guidance says extinguishers should be chosen by rating, not by size, weight or litres. A smaller extinguisher that achieves 13A is as effective as a larger one with the same rating.

How many fire extinguishers do you need and where should they go?

The number and type should come from your fire risk assessment. Small premises may need only one or two suitable extinguishers. Larger or more complex buildings need more, usually sited on escape routes at each floor level. For the Class A risk, government guidance says one water-based extinguisher for about every 200 square metres of floor space, with at least two per floor, will normally be adequate, and ideally nobody should have to travel more than 30 metres to reach one. British Standard BS 5306-8 covers the detailed selection and positioning of portable extinguishers, and a competent fire safety engineer can apply it to your building.

London Fire Brigade guidance on siting:

• Put extinguishers in conspicuous positions on escape routes, preferably near exit doors.
• Group them into fire points where possible, with the right mix of types for the nearby risks.
• Use signs, and directional arrows where needed, if an extinguisher is not in plain view.
• Mount them on wall brackets or stands. Stands make it obvious when one is missing.

The legal duty sits in Article 13 of the Regulatory Reform (Fire Safety) Order 2005: the responsible person must provide appropriate firefighting equipment where necessary and make sure it is easily accessible, simple to use and indicated by signs. See our guide to the Fire Safety Order for the wider duties.

Servicing and checking fire extinguishers

London Fire Brigade guidance says extinguishers need a basic service once a year by a competent person, with extended servicing in line with BS 5306-3. Between services, staff should check that each extinguisher is in place, undamaged, unused, with its seal intact and the pressure gauge (where fitted) reading correctly. Government guidance says a monthly check is normally enough. Keep a record of all maintenance and checks.

Some newer “life-cycle” extinguishers are designed to last 20 years with manufacturer refurbishment at 10 years. They do not need a traditional service contract, but they still need a visual inspection at least once a year by trained staff. Your fire marshals are often the people who carry out these routine checks.

Frequently asked questions

Where to learn more

• Fire Warden and Fire Marshal Training: extinguisher types, classes of fire and a practical extinguisher exercise
• Fire Awareness Training: half a day for all staff, with an optional extinguisher practical
• Classes of fire explained
• The fire triangle explained
• AFFF fire extinguisher ban: what duty-holders need to do
• Fire risk assessment: a UK guide