What Are the Different Types of Fire Extinguishers?
The main types of fire extinguishers used in UK commercial premises are water, foam, carbon dioxide, dry powder and wet chemical. Water-mist and specialist extinguishers are also available for particular risks.
Each type contains a different extinguishing medium. Consequently, an extinguisher that is effective on burning paper may be unsuitable for electrical equipment, flammable liquids, cooking oils or combustible metals.
For example, an office may require water-based protection for paper and furniture, together with carbon dioxide extinguishers near significant electrical equipment. Meanwhile, a commercial kitchen may require a wet chemical extinguisher for cooking-oil risks.
At
AK Fire Safety
,
we provide professional
fire extinguisher supply, commissioning, installation and servicing
for businesses throughout the United Kingdom.
What Are the Seven Main Fire Extinguisher Types?
The main extinguisher categories found in UK premises are:
- Water fire extinguishers
- Foam fire extinguishers
- Carbon dioxide fire extinguishers
- Dry powder fire extinguishers
- Wet chemical fire extinguishers
- Water-mist fire extinguishers
- Specialist Class D metal-fire extinguishers
Additional clean-agent and risk-specific products are available. However, suitability should always be confirmed from the extinguisher’s certified fire rating, manufacturer instructions and the premises-specific fire risk assessment.
Understanding the Different Classes of Fire
Fires are classified according to the material or fuel involved. The fire classification helps determine which extinguishing medium may be suitable.
Class A
Solid combustible materials such as paper, cardboard, timber, fabrics, furniture and many plastics.
Class B
Flammable or combustible liquids such as petrol, diesel, paint, solvents and some adhesives.
Class C
Flammable gases such as propane, butane, methane and liquefied petroleum gas.
Class D
Combustible metals such as magnesium, sodium, potassium and certain metal powders.
Class F
High-temperature cooking oils and fats, including oil used in commercial deep-fat fryers.
Electrical Equipment
Electricity is an additional hazard rather than a separate UK fire class while equipment remains energised.
Electrical Fire Classification Explained
Electrical equipment is often informally described as a Class E fire risk. However, the UK classification system does not formally use Class E. Once the electrical supply is safely isolated, the remaining fire is classified according to the material that continues to burn.
1. Water Fire Extinguishers
Water fire extinguishers are primarily designed for Class A fires involving solid combustible materials. They work by absorbing heat from the burning material and cooling it below its ignition temperature.
Water extinguishers are commonly found in offices, schools, shops, warehouses, residential communal areas and other premises containing paper, cardboard, timber and textiles.
Water Extinguishers May Be Suitable For:
- Paper and cardboard
- Wood and timber
- Textiles and fabrics
- Furniture
- Many ordinary Class A combustible materials
Standard Water Extinguishers Must Not Be Used On:
- Live electrical equipment
- Flammable liquids
- Flammable gases
- Cooking oils and fats
- Combustible metals
Common Water Extinguisher Variations
Water-based extinguishers can include plain water, water with additives and specialised water-spray products. Their fire ratings and approved applications can differ.
Therefore, users should follow the instructions and fire ratings printed on the individual extinguisher rather than assuming that every water-based product performs in the same way.
2. Foam Fire Extinguishers
Foam fire extinguishers are generally designed for Class A solid combustible fires and suitable Class B flammable-liquid fires.
The foam helps cool burning materials. On suitable liquid fires, it can also form a blanket across the fuel surface, reducing the release of flammable vapour and helping to prevent reignition.
Foam Extinguishers May Be Suitable For:
- Paper and cardboard
- Wood and textiles
- Petrol and diesel risks where appropriately rated
- Paint and compatible solvents
- Mixed Class A and Class B risks
Foam Extinguishers Are Generally Unsuitable For:
- High-temperature cooking oils
- Flammable gases
- Combustible metals
- Live electrical equipment unless specifically tested and approved
How Should Foam Be Applied?
Foam should be applied carefully to a suitable flammable-liquid fire. Directing a powerful jet into the liquid can splash or spread the burning fuel.
Staff should receive appropriate instruction before attempting to use firefighting equipment.
3. Carbon Dioxide Fire Extinguishers
Carbon dioxide extinguishers, commonly known as CO₂ extinguishers, are often selected for significant electrical-equipment risks because carbon dioxide does not leave a powder, foam or water residue.
The extinguisher releases carbon dioxide gas through a discharge horn. The gas reduces the oxygen immediately available around the flame and provides limited cooling.
CO₂ Extinguishers May Be Suitable For:
- Computers and office equipment
- Electrical switchgear
- Control panels
- Server and communications equipment
- Some small Class B liquid fires
- Areas where extinguisher residue could damage equipment
CO₂ Extinguisher Limitations:
- It provides limited cooling.
- Class A materials may reignite.
- The gas can disperse quickly outdoors.
- It is unsuitable for cooking-oil fires.
- It is unsuitable for combustible metals.
- Discharge in confined areas may affect breathable air.
The Discharge Horn Can Become Extremely Cold
The horn of some CO₂ extinguishers can become extremely cold during discharge. Users should hold the extinguisher using only the designated operating components and insulated handles.
BAFE guidance based on BS 5306-8 states that electrically non-conductive media, such as carbon dioxide, non-conductive powder or clean agent, should be used on live electrical equipment.
4. Dry Powder Fire Extinguishers
Dry powder extinguishers release a fine chemical powder that interrupts the chemical chain reaction sustaining the fire.
General ABC powder extinguishers can carry ratings for Class A, Class B and Class C fires. However, their broad fire ratings do not mean they are suitable for every building.
Possible Powder Extinguisher Applications:
- Outdoor industrial risks
- Fuel-storage areas
- Some workshops
- Vehicle-related risks
- Flammable gas hazards
- Mixed outdoor Class A, B and C risks
Disadvantages of Dry Powder:
- Powder can reduce visibility.
- Discharge can affect breathing.
- It can contaminate large indoor areas.
- It may damage sensitive electrical equipment.
- It provides limited cooling.
- Reignition may occur after flames are controlled.
Dry powder is generally not the preferred choice in offices, schools, healthcare premises, care homes and other occupied indoor environments unless a competent assessment identifies a specific need.
Powder for Gas Fires
Extinguishing a flammable-gas flame without controlling the gas supply can allow unburnt gas to continue escaping. Gas-related fire procedures require specialist assessment, emergency planning and safe fuel isolation arrangements.
5. Wet Chemical Fire Extinguishers
Wet chemical fire extinguishers are primarily designed for Class F fires involving high-temperature cooking oils and fats.
The agent cools the burning oil and creates a soap-like sealing layer across its surface. This process helps prevent oxygen from reaching the fuel and reduces the risk of reignition.
Wet Chemical Extinguishers Are Commonly Used In:
- Commercial kitchens
- Restaurants and cafés
- Takeaways
- Hotels
- School kitchens
- Care-home kitchens
- Premises containing commercial deep-fat fryers
Do Not Replace Wet Chemical Protection With:
- Standard water extinguishers
- Carbon dioxide extinguishers
- Standard foam extinguishers
- General-purpose powder without verified Class F approval
Never Apply Water to Burning Cooking Oil
Water can rapidly turn to steam beneath the hot oil and force burning material out of the appliance. This can cause the fire to spread violently across the surrounding area.
The wet chemical extinguisher should be selected according to the capacity of the fryer and its certified Class F rating.
6. Water-Mist Fire Extinguishers
Water-mist extinguishers release very fine water droplets rather than a conventional water jet.
The small droplets absorb heat efficiently and can reduce the oxygen available immediately around the flame. Water mist may also cause less water damage than a traditional water-jet extinguisher.
Potential Water-Mist Benefits:
- Effective cooling on suitable fires
- Reduced water discharge
- Lower collateral water damage
- Some products carry multiple fire ratings
- Some products have electrical test approval
Important Water-Mist Limitations:
- Products do not all carry the same fire ratings.
- Electrical suitability must be confirmed.
- Class F capability must not be assumed.
- Performance depends on the nozzle and product design.
- The certified label must be checked before selection.
BAFE guidance based on BS 5306-8:2023 states that water or water-based extinguishers should be provided to cool individual small rechargeable lithium-ion devices that are no longer charging. Larger battery risks require specialist assessment.
7. Class D Metal-Fire Extinguishers
Class D extinguishers contain specialist powder intended for combustible-metal fires.
The correct extinguishing agent depends on the metal involved. Therefore, a general-purpose ABC powder extinguisher must not automatically be treated as suitable for a metal fire.
Class D Risks May Be Found In:
- Metal-processing facilities
- Engineering workshops
- Laboratories
- Specialist manufacturing premises
- Machining processes producing combustible swarf
- Areas containing reactive metal powders
Specialist Selection Is Essential
Water, foam and unsuitable powder can react dangerously with certain burning metals. The extinguisher must be selected for the specific metal and process involved.
Current UK colour-coding guidance uses signal violet to identify Class D metal-fire powder, distinguishing it from blue-labelled general powder extinguishers.
What Are Clean-Agent Fire Extinguishers?
Clean-agent extinguishers use an electrically non-conductive extinguishing medium designed to leave little or no residue.
They may be considered for:
- Computer facilities
- Telecommunications equipment
- Laboratories
- Control rooms
- Archives and museums
- Sensitive electronic equipment
Product availability, environmental restrictions, fire ratings and manufacturer support should be reviewed before selecting a clean-agent extinguisher.
Fire Extinguisher Types Comparison Table
| Extinguisher Type | Identification Colour | Common Applications | Main Limitations |
|---|---|---|---|
| Water | Red | Class A solids, including paper, wood and textiles. | Standard water must not be used on live electrical equipment, flammable liquids or cooking oils. |
| Foam | Cream | Class A materials and suitable Class B liquids. | Generally unsuitable for cooking oils, gases, metals and unapproved electrical use. |
| CO₂ | Black | Live electrical equipment and limited Class B risks. | Limited cooling, possible reignition and rapid outdoor dispersal. |
| Dry powder | Blue | Suitable outdoor Class A, B and C risks. | Reduces visibility, contaminates equipment and provides limited cooling. |
| Wet chemical | Yellow | Class F cooking oils and fats. | Primarily intended for specialist kitchen risks. |
| Water mist | Usually red | Depends on the product’s certified ratings. | Capabilities vary significantly between products. |
| Class D powder | Signal violet | Specific combustible-metal risks. | The agent must be compatible with the metal involved. |
| Clean agent | Product dependent | Sensitive electrical and specialist environments. | Selection depends on approval, environmental requirements and availability. |
Fire Extinguisher Colour Codes Explained
Modern UK portable extinguishers normally have predominantly red bodies. A coloured identification panel shows the extinguishing medium.
- Red: water and many water-based extinguishers
- Cream: foam
- Blue: general-purpose dry powder
- Black: carbon dioxide
- Yellow: wet chemical
- Signal violet: Class D metal-fire powder
Always Read the Extinguisher Label
Colour coding supports quick identification, but the user should also check the operating instructions, fire ratings and safety warnings printed on the extinguisher.
Read our complete
fire extinguisher colours guide
.
How Do You Choose the Correct Extinguisher Type?
Extinguisher selection should follow the findings of the building’s fire risk assessment. A competent person should identify the materials, equipment and processes that could become involved in a fire.
Identify the Fuel
Determine whether the area contains solid combustibles, liquids, gases, oils, metals or batteries.
Consider Electrical Hazards
Identify equipment that may remain energised during the early stages of a fire.
Check the Environment
Consider whether powder, water, foam or gas discharge could create additional hazards.
Review Occupants
Consider staff, visitors, children, residents and anyone who may need assistance.
Check Fire Ratings
Compare the extinguisher’s certified rating with the protection required for the hazard.
Use a Competent Provider
Obtain professional selection, positioning and on-site commissioning.
BS 5306-8:2023 provides current recommendations for selecting and positioning portable extinguishers used to protect buildings, premises and their contents.
More information is available from the
British Standards Institution
.
Which Extinguisher Types Do Common Buildings Need?
The following examples provide general guidance only. Every premises should receive a risk-specific assessment.
| Premises | Typical Fire Risks | Possible Extinguisher Provision |
|---|---|---|
| Offices | Paper, furniture, computers and electrical equipment. | Suitable Class A protection with CO₂ near significant electrical risks. |
| Retail premises | Packaging, displays, furniture and electrical equipment. | Class A protection with suitable additional provision for electrical or specialist risks. |
| Commercial kitchens | Cooking oils, electrical appliances and ordinary combustible materials. | Wet chemical for Class F risks, with suitable electrical and Class A protection. |
| Warehouses | Packaging, stored materials, vehicles, machinery and battery charging. | A risk-specific combination based on the goods and processes present. |
| Schools | Paper, furniture, kitchens, laboratories and electrical equipment. | Class A protection with CO₂ and specialist kitchen or laboratory extinguishers where required. |
| Care homes | Furniture, textiles, electrical equipment, kitchens and vulnerable residents. | Carefully selected units that consider both the fire risk and occupant safety. |
| Workshops | Machinery, flammable liquids, timber, gas cylinders and hot work. | A combination selected for the materials, processes and environmental conditions. |
| Server rooms | Energised electronic equipment and surrounding combustible materials. | CO₂ or an appropriate clean agent, supported by suitable protection for nearby Class A risks. |
Similar Businesses Can Have Different Requirements
Two premises within the same industry may store different materials, use different machinery or have different layouts. Therefore, a generic extinguisher package should not replace a site-specific assessment.
Which Extinguisher Should Be Used on Electrical Equipment?
Carbon dioxide is commonly selected for live electrical equipment because it is electrically non-conductive and does not leave a damaging residue.
However, the appropriate solution depends on:
- The voltage and type of equipment
- The size of the potential fire
- The presence of surrounding combustible material
- The room size and ventilation
- The risk of reignition
- The availability of safe electrical isolation
BAFE publishes guidance on extinguishers for
live electrical equipment
.
Which Extinguisher Is Suitable for Lithium-Ion Batteries?
Lithium-ion battery incidents can involve rapid heating, flammable gases and repeated reignition. The correct protection depends on the battery chemistry, size, charging arrangement and number of batteries present.
Small mobile-device risks should not be treated in the same way as:
- Electric vehicles
- Electric bicycles and scooters
- Mobility equipment
- Industrial battery banks
- Energy-storage systems
- Large battery-charging facilities
Products marketed for lithium-ion batteries should be assessed carefully. Product test evidence, fire rating, cooling ability and manufacturer limitations should be reviewed by a competent person.
Read the
BAFE guidance for individual small lithium-ion batteries
.
Do New Fire Extinguishers Need Commissioning?
New extinguishers should be commissioned at the premises by a competent technician before they are placed into service.
On-site commissioning helps confirm:
- The extinguisher is the correct type.
- The fire rating is suitable.
- The cylinder has not suffered transit damage.
- The operating components are complete.
- The pressure or weight is correct.
- The extinguisher is positioned appropriately.
- The mounting bracket or stand is secure.
- Suitable identification signage is provided.
- The extinguisher is recorded and labelled.
BS 5306-3 covers the commissioning and maintenance of portable fire extinguishers, while BS 5306-8 covers their selection and positioning.
BAFE provides additional
fire extinguisher guidance
for responsible persons and organisations.
How Often Should Different Extinguisher Types Be Serviced?
Portable extinguishers should normally receive a basic service every 12 months by a competent technician.
The responsible person should also arrange routine visual inspections. Monthly checks are widely recommended, with more frequent inspections where circumstances require them.
Routine Extinguisher Check
- Confirm the extinguisher is in its designated location.
- Check that it remains visible and accessible.
- Inspect the cylinder for damage or corrosion.
- Check the pressure gauge where one is fitted.
- Confirm the safety pin and tamper seal are intact.
- Check the hose, horn or nozzle.
- Confirm the instructions remain legible.
- Check the bracket or stand is secure.
- Record and report any defect.
Learn more in our guide:
How Often Should Fire Extinguishers Be Serviced?
Who Is Responsible for Fire Extinguishers?
The responsible person must assess the fire risks and provide appropriate fire-safety measures for the premises.
Depending on the building, the responsible person may be:
- An employer
- A business owner
- A landlord
- An occupier
- A managing agent
- A facilities manager
- Another person who controls the premises
Official information is available from
GOV.UK workplace fire-safety guidance
.
Different Fire Extinguisher Types: Key Points
- No extinguisher is suitable for every type of fire.
- Water is primarily intended for Class A combustible solids.
- Foam can protect suitable Class A and Class B risks.
- CO₂ is commonly used for significant electrical-equipment risks.
- Dry powder can protect some mixed outdoor risks but creates secondary hazards indoors.
- Wet chemical is designed primarily for Class F cooking-oil fires.
- Water-mist capabilities vary between products.
- Class D metal fires require specialist powder.
- Colour coding should not replace checking the extinguisher label.
- Selection must follow the fire risk assessment.
- New equipment should be commissioned on site.
- Professional servicing should normally take place annually.
Frequently Asked Questions
What are the five most common fire extinguishers?
The five most common types are water, foam, carbon dioxide, dry powder and wet chemical fire extinguishers.
Which extinguisher is used for paper and wood?
A suitably rated water, water-based or foam extinguisher is commonly used for Class A fires involving paper, cardboard, timber and textiles.
Which extinguisher is used for electrical equipment?
CO₂ is commonly used for significant live electrical-equipment risks because it is non-conductive and leaves no residue. The exact choice should be determined by the fire risk assessment.
Which extinguisher is used in a commercial kitchen?
A wet chemical extinguisher carrying a suitable Class F rating is normally required for high-temperature cooking oils and deep-fat fryers.
What is a blue-label extinguisher?
A blue identification label normally indicates a general-purpose dry powder extinguisher.
What is a black-label extinguisher?
A black identification label indicates a carbon dioxide or CO₂ fire extinguisher.
Can foam extinguishers be used on electrical equipment?
A standard foam extinguisher should not be used on live electrical equipment unless the individual product carries specific test approval and its instructions permit that application.
Can dry powder extinguishers be used indoors?
Dry powder can reduce visibility, affect breathing and contaminate equipment. Therefore, it is generally unsuitable for many occupied indoor areas unless a competent assessment supports its use.
Does every business need the same extinguisher types?
No. The required extinguisher combination depends on the building, materials, processes, electrical risks and findings of the fire risk assessment.
Do newly purchased extinguishers need commissioning?
Yes. New extinguishers should be commissioned at the premises by a competent technician to confirm that they are suitable, complete, undamaged and correctly positioned.
Related Fire Extinguisher Guides
Conclusion
The principal UK fire extinguisher types are water, foam, carbon dioxide, dry powder and wet chemical. Water mist, Class D powder and clean-agent extinguishers provide additional options for particular risks.
However, extinguisher types are not interchangeable. Each extinguishing medium has specific applications, advantages and limitations.
Therefore, the correct extinguisher provision should be determined through a suitable fire risk assessment and a competent survey of the premises.
Once selected, each extinguisher should be commissioned at the premises, installed in an accessible location, checked regularly and professionally maintained.
Most importantly, portable extinguishers should support safe evacuation rather than encourage anyone to take unnecessary risks. Building occupants should raise the alarm, follow the emergency procedure and withdraw immediately when a fire cannot be controlled safely.
Professional Fire Extinguisher Services
AK Fire Safety supplies, commissions, installs and maintains fire extinguishers for businesses and organisations throughout the United Kingdom.
Our services include:
- Fire extinguisher surveys
- Risk-appropriate extinguisher selection
- Supply and on-site commissioning
- Wall brackets, stands and signage
- Annual fire extinguisher servicing
- Extended servicing and overhauls
- Recharging and replacement
- Responsible disposal
- Multi-site maintenance programmes
- Nationwide service coverage
Telephone: 01604 459588
Email: sales@akfiresafety.co.uk