Fire Extinguisher Colours

All modern fire extinguishers in the UK are manufactured with a red body (known as Signal Red), in accordance with British Standard BS EN 3. The extinguisher type is identified by a coloured label or band, rather than the cylinder itself being fully coloured.

Although older-style fire extinguishers with fully coloured bodies (e.g. cream, blue, black) may still be found in some premises, they are no longer manufactured and should be replaced when they reach the end of their service life.

Halon fire extinguishers (previously identified by a green colour) are illegal in the UK and must not be used or supplied under any circumstances.

Because of strict colour coding and performance requirements, fire extinguishers used in UK workplaces must comply with BS EN 3 and be selected based on the findings of a fire risk assessment, not colour alone.

Different classes of fire require different extinguishing media. Selecting the wrong type of extinguisher can significantly increase risk to occupants. For this reason, Responsible Persons must ensure extinguishers are suitable for the hazards present and are correctly installed, labelled, and maintained.

Fire extinguishers supplied to commercial and public buildings are factory-certified to BS EN 3 and must be correctly commissioned, positioned, and recorded on site as part of the premises’ fire safety arrangements.

What Are the Fire Extinguisher Colours?

Although all extinguishers are now red, the following coloured labels or bands are used to identify the extinguisher type:

1. Blue – Dry Powder
2. Black – Carbon Dioxide (CO₂)
3. Cream – Foam
4. Red – Water (including spray or mist variants)
5. Yellow – Wet Chemical

These colour bands provide quick visual identification but should never be relied upon as the sole basis for extinguisher selection. Suitability must always be determined by a fire risk assessment.

1. Blue (Dry Powder Extinguishers)

Blue label extinguishers are often referred to as ABC extinguishers, as they may be suitable for Class A, B, and C fires. However, they are not recommended for use in enclosed or occupied spaces due to visibility impairment and inhalation risks.

Specialist dry powder extinguishers may also be used for certain Class D metal fires, but these are distinct products and must not be confused with standard ABC powder units.

How Do a Dry Powder Extinguishers Work?

Dry powder or chemical extinguishers work by coating the fuel or burning material with a thin layer of dust. This separates the fuel from the oxygen. It also works by interrupting the chemical reaction of a fire, which is why they are effective in putting out fires from classes A, B, and C.

Dry powder extinguishers work by coating the burning material and interrupting the chemical reaction of the fire, separating the fuel from oxygen.

Used on:

• Solid combustibles (wood, paper, textiles)
• Flammable liquids (petrol, diesel, oils)
• Flammable gases (LPG, acetylene)
• Electrical fires (up to 1000V, where appropriate)

Not used on:

• Cooking oil fires
• Fires above 1000V
• Occupied or confined indoor spaces

Who Might Need Dry Powder Extinguishers?

• Welding and flame-cutting premises
• Industrial boiler rooms
• Sites using flammable gases
• Garage forecourts

2. Black (Carbon Dioxide (CO2) Extinguishers)

CO₂ extinguishers are primarily intended for electrical fires and Class B flammable liquid fires. They leave no residue, making them suitable for protecting sensitive equipment.

How Do CO₂ Extinguishers Work?

CO₂ extinguishers work by displacing oxygen around the fire, effectively suffocating the flames.

Used on:

• Electrical equipment
• Flammable liquids

Not used on:

• Solid combustibles
• Cooking oil fires
• Fires involving deep-seated materials

Who Might Need Carbon Dioxide Extinguishers?

• Server rooms
• Electrical intake rooms
• Office environments
• Commercial premises with IT infrastructure

3. Cream (Foam Extinguishers)

Foam extinguishers are suitable for Class A and Class B fires, particularly where flammable liquids are present.

How Does a Foam Extinguisher Work?

Foam extinguishers work by forming a blanket over the burning surface, cooling the fire and cutting off oxygen.

Used on:

• Solid combustibles
• Flammable liquids

Not used on:

• Electrical fires
• Metal fires
• Cooking oil fires

Who Might Need Foam Extinguishers?

• Offices
• Warehouses
• Schools
• Retail premises

Many premises require a combination of foam and water extinguishers, depending on the fire risk assessment.

4. Red (Water Extinguishers)

Water extinguishers are the most commonly used and cost-effective option for Class A fires only.

How Does a Water Extinguisher Work?

Water extinguishers extinguish fire by cooling the burning material below its ignition temperature.

Used on:

• Wood
• Paper
• Textiles

Not used on:

• Electrical fires
• Flammable liquids
• Cooking oils and fats

Who Might Need Water Extinguishers?

• Offices
• Schools
• Residential buildings
• Warehouses storing organic materials

5. Yellow (Wet Chemical Extinguishers)

Wet chemical extinguishers are specifically designed for Class F fires, typically involving cooking oils and fats.

How Does a Wet Chemical Extinguisher Work?

Wet chemical extinguishers apply a fine mist and chemical solution, forming a soapy layer that cools and suppresses re-ignition.

Used on:

• Commercial cooking oil fires
• Limited Class A fires (where specified)

Not used on:

• Electrical fires
• Flammable gases
• Flammable metals

Who Might Need Wet Chemical Extinguishers?

• Restaurants
• Commercial kitchens
• Catering facilities

Why Is Extinguisher Colour Coding Necessary?

Colour bands provide rapid visual identification, which is essential during emergencies. All extinguishers should be clearly signed, accessible, and correctly mounted (typically with the handle around 1 metre from floor level).

Correct identification helps prevent dangerous misuse — for example, using water on a cooking oil fire can cause violent flare-ups and serious injury.

Why Did The Fire Extinguisher Colour Change?

Before 1997, extinguisher bodies were fully colour-coded. This changed with the introduction of BS EN 3, which standardised red bodies to:

• Improve visibility in smoke-filled environments
• Reduce confusion
• Align with international standards

What Are the Different Classes of Fire?

• Class A: Solid combustibles (wood, paper, textiles)
• Class B: Flammable liquids
• Class C: Flammable gases
• Class D: Combustible metals
• Electrical: Fires involving live electrical equipment
• Class F: Cooking oils and fats

Conclusion

All extinguishers should comply with BS EN 3 and be serviced at least annually by a competent person. Training should be provided so that staff understand when — and when not — to use an extinguisher safely.

We supply, install, commission, and maintain fire extinguishers as part of a fully compliant fire safety solution. Contact us to ensure your premises meet current UK fire safety requirements.