- Paper, cardboard and books
- Wood and many wood-based products
- Textiles and similar ordinary combustible materials
- Class A risks expressly covered by the extinguisher rating
Class A ordinary combustibles
Water fire extinguishers: uses, colour and safety guidance
Understand where conventional water extinguishers may be suitable, which fires they must not be used on and why the premises fire risk assessment should determine provision.
Page summary
Water extinguishers at a glance
The fire risk assessment should determine whether this extinguisher is appropriate, the fire rating required and where it should be positioned. Colour helps identification; it does not replace reading the label.
- Cools burning solid material
- Common in many low-risk workplaces
- Normally for Class A fires only
- Conventional water must not be used on live electrical equipment
Correct selection
What water extinguishers can—and cannot—be used for
No single portable extinguisher is suitable for every fire. Use only equipment selected for the premises and only on the classes and conditions stated on its label.
- Live electrical equipment
- Flammable liquids or gases
- Cooking oils and deep-fat fryers
- Combustible metals
- Any fire class not shown on the extinguisher label
How it controls fire
How a water extinguisher works
Water absorbs heat from the burning material. Sufficient cooling can reduce the fuel below the temperature needed to sustain combustion and helps control deep-seated Class A fires.
Performance depends on the extinguisher design, discharge pattern and fire rating. Water with additives may carry different ratings from a plain-water unit, so the label and manufacturer instructions matter.
Premises examples
Where this extinguisher may be considered
These are prompts for assessment, not ready-made specifications. Building use, quantities, people at risk and other protection can change the answer.
Offices and public buildings
Paper, furniture and other ordinary combustibles may make a rated water extinguisher appropriate alongside equipment for separate electrical risks.
Schools and community premises
Often used where the main fuel load is paper, textiles, display material and timber, subject to vandalism and user considerations.
Shops and stock areas
May suit ordinary combustible stock, but liquids, aerosols, cooking and electrical hazards need separate assessment.
Warehouses
Can support Class A protection where storage type, height, access and fire rating have been properly considered.
Before specifying equipment
Selection points that matter
Do not buy by colour or cylinder size alone. A competent selection considers the hazards, certified ratings, likely users, positioning and interaction with the emergency plan.
Fire rating
Capacity alone does not show capability. Check the certified Class A rating and confirm the combined provision is adequate for the premises.
Electrical separation
Do not position a conventional water extinguisher so users are likely to select it for energised equipment. Separate risks need suitable provision and clear training.
Temperature and location
Freezing conditions, access, mounting, travel distance and vulnerability to damage can affect specification and position.
User capability
Weight, discharge characteristics and the people expected to use equipment should form part of the assessment and training.
Life safety comes first
Portable extinguishers support escape; they do not make firefighting compulsory
Raise the alarm, begin the evacuation procedure and call 999. A person should only consider using an extinguisher if they have been instructed or trained, the fire is small, the correct unit is available, smoke is not affecting them and a clear escape route remains behind them. Never delay evacuation or take personal risk.
Inspection and servicing
Keep the provision usable and correctly specified
Routine checks should identify discharged, damaged, missing, obstructed or out-of-date equipment. Competent servicing should confirm condition, agent, rating, position, signage and records, while the fire risk assessment should be reviewed when hazards or layouts change.
BAFE’s SP101 scheme provides third-party certification for organisations that commission and maintain portable fire extinguishers. Certification can be useful evidence, but check that the provider’s current scope covers the work required.
Frequently asked questions
Water extinguisher FAQs
What colour is a water fire extinguisher in the UK?
Modern UK portable extinguishers generally have a red body. A conventional water extinguisher normally has no contrasting identification band, so read the agent name and fire rating on the label rather than relying on colour alone.
What fire class is a water extinguisher for?
It is normally intended for Class A fires involving ordinary solid combustibles such as paper, wood and textiles. Always check the rating printed on the particular unit.
Can a water extinguisher be used on electrical equipment?
A conventional water extinguisher should not be used on live electrical equipment because of shock and equipment risks. Some specialist water-based products have specific dielectric test claims, but only those documented instructions and ratings should be followed.
Are water extinguishers suitable for offices?
They can be suitable for the Class A content of an office, while a separately selected CO₂ or other appropriate unit may address electrical equipment. The full provision should follow the fire risk assessment.
How often should a water extinguisher be serviced?
Responsible persons should arrange routine visual checks and competent maintenance in line with the relevant standard, manufacturer instructions and fire risk assessment. Annual basic servicing is commonly used, with additional extended service or replacement requirements depending on the unit.
Sources and limitations
Guidance checked against authoritative UK sources
This is general information, not an extinguisher specification or instruction to fight a fire. The selection, number, rating and position of extinguishers depend on a suitable and sufficient fire risk assessment, recognised guidance, manufacturer instructions and the actual premises.