for businesses, landlords, schools, care providers and commercial organisations throughout the United Kingdom.

How Does a Fire Extinguisher Work?

A fire needs heat, fuel and oxygen to continue burning. This relationship is commonly described as the fire triangle.

A fire extinguisher controls a suitable fire by interfering with one or more of these elements. Depending on the extinguishing agent, it may:

• Cool the burning material below its ignition temperature.
• Smother the fire and reduce its access to oxygen.
• Create a barrier between fuel and the flames.
• Interrupt the chemical chain reaction within the fire.
• Displace oxygen around the flame for a limited period.

Should You Attempt to Fight a Fire?

Personal safety and evacuation always take priority over property protection. A fire extinguisher should only be considered when the fire is small, the correct equipment is available and the user has a clear route of escape.

What Are the Different Classes of Fire?

Fires are classified according to the material or fuel that is burning. Understanding the fire class helps determine which extinguishing agent may be suitable.

Fire Classes and Suitable Extinguisher Types

What Are the Main Types of Fire Extinguishers?

The most common portable fire extinguishers used in UK premises are water, foam, carbon dioxide, dry powder and wet chemical. Water-mist and specialist extinguishers are also available for particular applications.

Each extinguisher should display clear operating instructions, fire ratings and information about the extinguishing agent it contains.

Fire Extinguisher Types at a Glance

What Do Fire Extinguisher Colours Mean?

Modern portable extinguishers in the UK normally have predominantly red bodies. A coloured identification area or label indicates the extinguishing medium.

The main colour codes are:

• Red: water or water-based extinguishing medium
• Cream: foam
• Blue: general dry powder
• Black: carbon dioxide
• Yellow: wet chemical
• Signal violet: specialist Class D powder

How Do You Choose the Correct Fire Extinguisher?

Extinguisher selection should be based on the fire risk assessment and the hazards present within each area of the building.

A competent assessment should consider:

In addition, the selected extinguisher should be practical for the expected user. A unit that is too heavy or difficult to operate may not provide effective protection.

What Does the Fire Rating on an Extinguisher Mean?

The fire rating shows the extinguisher’s tested firefighting capability for particular fire classes.

For example, a water or foam extinguisher may display a Class A rating such as 13A, 21A or another value. A higher number generally represents a greater tested capacity against the relevant standard test fire.

A suitable foam extinguisher may also carry a Class B rating. Wet chemical products may carry a Class F rating that indicates their tested cooking-oil capability.

Which Fire Extinguisher Is Used for Electrical Fires?

CO₂ extinguishers are frequently selected for certain live electrical-equipment risks because they do not leave a residue. However, the exact choice should reflect the equipment, room conditions and other combustible materials nearby.

Typical areas may include:

• Server and communications rooms
• Electrical intake rooms
• Control panels
• Office computer areas
• Laboratories
• Plant rooms

A CO₂ extinguisher may control flames around energised equipment. Nevertheless, it provides limited cooling. If surrounding plastic, paper or other Class A material continues burning, another suitable extinguisher may also be necessary after the electrical supply has been safely isolated.

What Fire Extinguisher Is Suitable for Lithium-Ion Batteries?

Lithium-ion batteries can enter thermal runaway, producing heat, flammable gases and the possibility of reignition. These incidents can behave differently from ordinary electrical-equipment fires.

The correct response depends on:

• The battery chemistry
• Battery size and energy capacity
• Whether the battery is installed in equipment
• The number of batteries stored or charged
• Manufacturer instructions
• The availability of cooling and containment
• The building’s emergency procedures

Specialist products are marketed for battery incidents, but their ratings, test methods and limitations must be carefully reviewed. A product described as suitable for batteries should not be selected solely from marketing claims.

Larger risks involving electric vehicles, energy-storage systems, mobility devices or industrial battery banks require specialist fire-engineering and emergency-planning advice.

Read the Lithium Battery Fire Guide

Which Extinguishers Are Suitable for Common Premises?

Who Should Select and Commission Fire Extinguishers?

Selection, positioning and commissioning should be completed by a competent fire extinguisher organisation or technician.

A competent provider should be able to:

• Review the fire risks present.
• Select suitable extinguisher types and fire ratings.
• Determine appropriate quantities and positions.
• Check that products are suitable and undamaged.
• Commission extinguishers at the premises.
• Install brackets, stands and identification signs.
• Provide service labels and commissioning records.
• Explain routine inspection requirements.

BAFE recommends using a

BAFE SP101 registered organisation

for portable fire extinguisher commissioning and maintenance.

Important UK Fire Extinguisher Standards

Several British Standards support the selection, commissioning, maintenance and identification of portable fire extinguishers.

• BS 5306-3 – commissioning and maintenance of portable fire extinguishers.
• BS 5306-8:2023 – selection and positioning of portable fire extinguishers.
• BS 5306-9 – recharging portable fire extinguishers.
• BS 5306-10 – colour coding used to identify extinguishing media.
• BS EN 3 – product requirements and testing for portable fire extinguishers.
• BAFE SP101 – a competency scheme for portable fire extinguisher organisations and technicians.

Further information about the BS 5306 series is available from the

Fire Industry Association

.

How Many Fire Extinguishers Does a Business Need?

There is no single number of fire extinguishers that applies to every business. The quantity depends on the size, layout, fire risks, number of floors and extinguisher fire ratings within the premises.

The starting point should be a suitable and sufficient fire risk assessment. A competent extinguisher technician can then calculate the provision required for ordinary combustible materials and any additional specialist risks.

Factors affecting the number of extinguishers include:

• The total floor area of each storey
• The fire rating of each extinguisher
• The number of floors
• The number and position of exits
• The building layout and travel distances
• Class A combustible materials
• Flammable liquids and gases
• Commercial cooking equipment
• Electrical equipment and switchgear
• Workshops, plant rooms and laboratories
• External storage or vehicle risks
• People who may need assistance during evacuation

What Is the Basic Class A Extinguisher Provision?

Class A provision protects ordinary combustible materials such as paper, cardboard, timber, textiles and many furnishings.

Extinguisher fire ratings are used to calculate the available Class A protection. For example, an extinguisher marked 13A has a lower tested Class A capability than one marked 21A or 27A.

The exact quantity should be confirmed by a competent technician using:

• The current version of BS 5306-8
• The building’s fire risk assessment
• The certified ratings shown on the extinguishers
• The floor area and layout
• Travel distances to suitable equipment
• Any significant variations from ordinary commercial use

A smaller number of high-rated extinguishers may provide the required numerical rating. However, practical distribution and access still matter. One large extinguisher positioned far from the risk may not offer suitable coverage.

Do Specialist Risks Need Additional Extinguishers?

Yes. Basic Class A provision does not necessarily protect every hazard within the premises.

Where Should Fire Extinguishers Be Positioned?

Fire extinguishers should be clearly visible, readily accessible and positioned where they can be reached safely during the early stages of a fire.

General positioning principles include:

• Place extinguishers on normal escape routes.
• Position general extinguishers near exits, stairways or fire points.
• Keep equipment visible and free from obstruction.
• Use consistent positions throughout the building.
• Provide suitable signs where identification is not immediately obvious.
• Protect extinguishers from weather, impact, corrosion and misuse.
• Position specialist extinguishers near the relevant risk.
• Avoid placing users where they could become trapped by fire.
• Keep extinguisher instructions facing outwards.
• Do not hide extinguishers behind doors, curtains, stock or furniture.

Should Fire Extinguishers Be Positioned Near Exits?

General-purpose extinguishers are commonly positioned near exits, final exits, stairways and recognised fire points.

This approach helps because:

• The extinguisher is easier to find.
• The user can maintain access to an escape route.
• Equipment can be distributed consistently.
• The extinguisher is less likely to be hidden among furniture or equipment.
• Building occupants become familiar with fire-point locations.

Nevertheless, specialist extinguishers may need to be positioned closer to the hazard. For example, a CO₂ extinguisher may be placed near an electrical intake room, while a wet chemical extinguisher may be positioned near the exit from a commercial kitchen.

Where Should Kitchen Fire Extinguishers Be Positioned?

Commercial-kitchen extinguishers should be accessible without requiring a person to move towards or reach across burning cooking equipment.

Suitable considerations include:

• Position wet chemical extinguishers near the kitchen exit.
• Keep them a safe distance from fryers and cooking appliances.
• Do not position them directly above or beside the main hazard.
• Ensure staff can reach the equipment while maintaining an escape route.
• Provide suitable provision for electrical and Class A risks.
• Install a suitable fire blanket where required by the assessment.
• Clearly identify each extinguisher and its intended use.

Where Should CO₂ Extinguishers Be Positioned?

CO₂ extinguishers should be positioned near significant electrical risks while remaining accessible from a safe approach.

Possible locations include:

• Near electrical intake rooms
• Outside server and communications rooms
• Near switchgear and control panels
• Near significant office electrical equipment
• Near laboratory electrical equipment
• Near manufacturing control systems

The unit should not be positioned where a user must enter a smoke-filled or electrically hazardous area to retrieve it.

How High Should Fire Extinguishers Be Mounted?

Fire extinguishers can be secured to wall brackets or placed on suitable purpose-designed stands.

The mounting arrangement should:

• Keep the extinguisher secure.
• Allow it to be removed without difficulty.
• Prevent accidental damage or movement.
• Keep operating instructions visible.
• Be suitable for the extinguisher’s weight.
• Support accessibility for expected users.

Common industry practice is to install lighter portable extinguishers with the carrying handle no higher than approximately 1.5 metres from floor level. Heavier extinguishers are generally installed lower, commonly with the handle no higher than approximately one metre.

The exact position should follow the applicable standard, extinguisher weight, manufacturer instructions and accessibility assessment.

Can Fire Extinguishers Be Placed on Stands?

Yes. Purpose-designed extinguisher stands can be suitable where wall mounting is impractical, undesirable or prohibited.

Stands are commonly used in:

• Reception areas
• Listed or heritage buildings
• Glass-walled offices
• Temporary premises
• Construction sites
• Retail premises
• Exhibition spaces
• Buildings where drilling into walls is restricted

The stand should be stable, clearly visible and positioned so that it does not create a trip or obstruction hazard.

Can Fire Extinguishers Be Kept in Cabinets?

Cabinets can protect extinguishers installed outdoors, in dusty industrial areas or where they may suffer accidental damage.

However, the cabinet should:

• Be clearly identified.
• Allow rapid access.
• Be suitable for the installed environment.
• Protect the extinguisher from rain and contamination.
• Not require a key that could delay emergency access.
• Be included in routine inspections.

An indoor cupboard is not normally suitable where it conceals the extinguisher or makes access difficult. Where equipment is enclosed, clear external signage is particularly important.

Do Fire Extinguishers Need Signs?

Suitable fire-extinguisher identification signs can help people locate equipment and understand its intended use.

A sign may show:

• The location of the extinguisher
• The extinguishing medium
• The fire classes for which it is suitable
• Common hazards on which it must not be used
• Basic operating instructions

Signs should be visible and positioned close to the equipment. They should not contradict the markings printed on the extinguisher.

Identification signs are especially useful where:

• The extinguisher is not immediately visible.
• Several extinguisher types are positioned together.
• Equipment is installed inside a cabinet.
• The premises receives members of the public.
• The extinguisher is mounted at a low level.

Do New Fire Extinguishers Need Commissioning?

New fire extinguishers should be commissioned at the premises by a competent technician before they are placed into service.

Commissioning is different from simply purchasing an extinguisher online or having it delivered. The technician checks that the unit is suitable, complete, correctly assembled and positioned for the risks at the actual premises.

Who Can Commission Fire Extinguishers?

Commissioning should be carried out by a competent fire extinguisher technician with suitable knowledge, training, equipment and experience.

Competence should include the ability to:

• Interpret the fire risk assessment.
• Apply relevant British Standards.
• Select suitable extinguisher types and ratings.
• Recognise damaged or unsuitable equipment.
• Complete safe pressure-vessel inspections.
• Install brackets, stands and signs.
• Complete accurate records and labels.

BAFE operates the SP101 scheme to assess the competence of portable fire extinguisher organisations and their employed technicians.

Learn more from the

BAFE fire extinguisher service and maintenance guidance

.

How Often Should Fire Extinguishers Be Checked?

Fire extinguishers should receive regular visual inspections by the responsible person or a suitably instructed member of staff.

Monthly checks are widely used because they can identify damage, discharge, obstruction and tampering between professional services.

Additional checks may be appropriate:

• After building work
• After a fire alarm or evacuation
• After an extinguisher has been moved
• After vandalism or suspected tampering
• After severe weather
• Where equipment is installed outdoors
• In high-risk industrial environments
• Following a change in occupancy or layout

What Is Included in a Monthly Fire Extinguisher Check?

CO₂ extinguishers do not normally have a pressure gauge. Therefore, the absence of a gauge on a CO₂ unit is not automatically a fault.

What Does It Mean If the Gauge Is in the Red?

A gauge needle in the low-pressure red zone may indicate that pressure has escaped or that the extinguisher has been partly discharged.

A needle in a high-pressure red zone may indicate overpressure or another fault.

In either situation:

• Do not assume the extinguisher is ready for use.
• Record and report the defect.
• Arrange inspection by a competent technician.
• Provide suitable temporary replacement protection where required.
• Do not attempt to recharge or dismantle the extinguisher yourself.

What If the Tamper Seal or Safety Pin Is Missing?

A missing seal or pin may indicate that the extinguisher has been used, interfered with or made unsafe.

The responsible person should:

• Remove the extinguisher from normal reliance.
• Record the defect.
• Arrange a competent inspection.
• Provide replacement cover if necessary.
• Investigate repeated tampering or vandalism.

A new seal should not simply be fitted without checking the extinguisher’s condition, contents and pressure.

How Often Should Fire Extinguishers Be Professionally Serviced?

Portable fire extinguishers should normally receive a basic service every 12 months by a competent person.

Annual servicing helps confirm that the equipment remains:

• Safe
• Reliable
• In good repair
• Suitable for the identified risk
• Correctly positioned
• Properly labelled
• Ready for emergency use

The service date should not be treated as the only time extinguishers are considered. Monthly visual checks and prompt defect reporting remain essential throughout the year.

What Is Included in an Annual Fire Extinguisher Service?

The exact procedure depends on the extinguisher type, construction and condition.

A professional service may include:

• Checking that the correct extinguishers remain provided
• Reviewing changes to the premises or hazards
• Checking the cylinder for corrosion, dents and damage
• Inspecting the valve and operating mechanism
• Checking the pressure gauge where fitted
• Weighing the extinguisher where required
• Inspecting hoses, horns and nozzles
• Checking the safety pin and tamper seal
• Checking operating instructions and product markings
• Inspecting brackets, stands and cabinets
• Checking extinguisher signs
• Replacing approved service components where required
• Applying a service label
• Completing a service report

Should the Technician Review the Fire Risk Assessment?

The technician should have access to relevant fire-risk information before or during maintenance.

This helps establish:

• Why particular extinguisher types were selected
• Whether specialist risks are present
• Whether the building layout has changed
• Whether previous recommendations remain outstanding
• Whether equipment has been deliberately varied from standard provision
• Whether vulnerable occupants or unusual processes affect selection

Where no suitable fire risk assessment is available, the technician should report the concern to the responsible person.

What Is an Extended Fire Extinguisher Service?

An extended service is a more detailed procedure carried out at specified intervals for relevant extinguisher types.

During an extended service, the extinguisher may be discharged, internally inspected, serviced and recharged in accordance with the applicable standard and manufacturer instructions.

The procedure may include:

• Controlled discharge of the extinguishing medium
• Internal examination of the cylinder
• Inspection of internal linings where present
• Checking valves and operating mechanisms
• Replacing approved seals and components
• Refilling with the correct extinguishing medium
• Repressurising using the correct method
• Leak testing
• Applying updated service information

How Often Is an Extended Service Required?

The technician should confirm the precise interval using the extinguisher type, date information, current British Standard and manufacturer instructions.

Should an Extinguisher Be Refilled or Replaced at Extended Service?

Some extinguishers can be serviced and recharged. In other cases, replacement may be more practical or appropriate.

Replacement may be recommended when:

• The extinguisher is corroded or damaged.
• Replacement parts are unavailable.
• The manufacturer no longer supports the unit.
• The internal lining has deteriorated.
• The cost of servicing approaches the cost of replacement.
• The extinguisher no longer suits the risk.
• The agent has become obsolete or environmentally undesirable.
• The unit cannot be safely or reliably maintained.

Do Fire Extinguishers Expire?

Fire extinguishers do not all have one universal expiry date. Their service life depends on condition, construction, environment, manufacturer support and maintenance history.

A well-maintained extinguisher may remain in service for many years. However, age alone does not prove that it remains safe or reliable.

An extinguisher may require replacement because of:

• Corrosion
• Dents, cuts or gouges
• Damage to the valve or operating mechanism
• Pressure loss
• Repeated leakage
• Damaged hose, horn or nozzle
• Split or detached internal lining
• Degraded plastic components
• Missing or illegible product information
• Obsolete design or unavailable parts
• Uncertain service history
• Failure during servicing or overhaul

When Should a Fire Extinguisher Be Replaced Immediately?

What Should Happen After an Extinguisher Is Used?

Any extinguisher that has been used, even briefly, should be removed from normal reliance and inspected by a competent technician.

The responsible person should:

• Arrange immediate replacement fire cover.
• Record which extinguisher was used.
• Report the incident and update the fire logbook.
• Arrange competent inspection, recharge or replacement.
• Clean any extinguisher residue safely.
• Review why the fire occurred.
• Review whether the equipment and emergency procedures were effective.

Replacing the safety pin or seal does not restore a discharged extinguisher.

Can Fire Extinguishers Be Refilled?

Many rechargeable extinguishers can be refilled by a competent service provider using the correct agent, components and charging equipment.

Refilling may be appropriate:

• After an extinguisher has been discharged
• During a scheduled extended service
• After controlled maintenance
• Where the cylinder and components remain serviceable
• Where approved replacement agents and parts remain available

Disposable or non-rechargeable extinguishers should normally be replaced when discharged or defective.

The correct extinguishing medium must be used. Mixing agents or using unapproved substitutes can reduce performance and damage the extinguisher.

How Should Old Fire Extinguishers Be Disposed Of?

Fire extinguishers should not normally be placed in general waste because they are pressurised containers and may contain controlled extinguishing agents.

Disposal should be arranged through:

• A competent fire extinguisher service company
• An authorised waste-management facility
• A recycling service able to handle pressurised cylinders
• A local facility that specifically confirms acceptance

Before recycling, the extinguisher may need to be safely depressurised and separated into:

• Metal cylinder
• Valve components
• Plastic parts
• Hoses and horns
• Extinguishing medium

Are Fire Extinguishers Required by Law?

UK fire-safety legislation generally requires the responsible person to assess fire risks and provide suitable general fire precautions.

The legislation does not simply prescribe the same extinguisher package for every building. Instead, the responsible person must determine appropriate firefighting equipment through the fire risk assessment.

In England and Wales, the Regulatory Reform (Fire Safety) Order 2005 applies to workplaces and many non-domestic premises. It also applies to the common parts of buildings containing two or more domestic premises.

Government guidance states that the responsible person must:

• Carry out and regularly review a fire risk assessment.
• Tell staff about identified fire risks.
• Put appropriate fire-safety measures in place.
• Maintain those fire-safety measures.
• Plan for emergencies.
• Provide suitable information, instruction and training.

Read the official

GOV.UK workplace fire-safety responsibilities

.

Who Is the Responsible Person?

Depending on the premises, the responsible person may be:

• An employer
• A business owner
• A landlord
• A building owner
• An occupier
• A managing agent
• A facilities manager acting on behalf of the duty holder
• Another person with control over the premises

Where several people share control, they may need to cooperate and coordinate their fire-safety arrangements.

What Does Article 17 of the Fire Safety Order Require?

Article 17 requires relevant fire-safety facilities, equipment and devices to be subject to a suitable system of maintenance and kept in efficient working order and good repair.

For fire extinguishers, this means the responsible person should arrange:

• Regular visual inspections
• Professional maintenance
• Prompt investigation of defects
• Recharge or replacement after use
• Accurate service records
• Review following changes to the premises or fire risks

Read

Article 17 of the Regulatory Reform (Fire Safety) Order 2005

.

What Is BS 5306?

BS 5306 is a series of British Standards covering fire-extinguishing installations and equipment on premises.

Relevant parts include:

Standards provide recognised good-practice guidance. However, they should be applied alongside the fire risk assessment, manufacturer instructions and applicable legislation.

What Is BAFE SP101?

BAFE SP101 is a competency scheme covering portable fire extinguisher organisations and their employed technicians.

The scheme provides third-party assessment relating to:

• Organisation competence
• Technician competence
• Quality-management arrangements
• Commissioning work
• Maintenance procedures
• Application of relevant standards

BAFE states that individual extinguisher technicians must work for an organisation that has achieved third-party certification and BAFE SP101 registration to hold scheme registration.

Do Employees Need Fire Extinguisher Training?

Staff should receive fire-safety information and instruction appropriate to their roles and the premises.

Training may include:

• How to raise the alarm
• How to contact the fire and rescue service
• The building evacuation procedure
• The different extinguisher types provided
• Which fires should not be tackled
• How to maintain an escape route
• How to use an extinguisher safely
• When to stop firefighting and evacuate

Training should never pressure employees into fighting a fire. Evacuation and personal safety remain the priority.

How Do You Use a Fire Extinguisher?

Operating methods vary, so users should follow the instructions printed on the extinguisher and any training they have received.

The word PASS is often used as a basic memory aid:

Common Fire Extinguisher Mistakes

Fire Extinguisher Management Checklist

Frequently Asked Questions About Fire Extinguishers

Professional Fire Extinguisher Services

AK Fire Safety supplies, commissions, installs and maintains portable fire extinguishers for businesses and organisations throughout the United Kingdom.

Our fire extinguisher services include:

• Fire extinguisher site surveys
• Extinguisher selection and risk assessment support
• Supply of suitable extinguishers
• On-site commissioning
• Wall-bracket and stand installation
• Fire extinguisher signage
• Annual basic servicing
• Extended servicing
• CO₂ extinguisher overhauls
• Refilling and recharging
• Replacement of damaged or obsolete units
• Responsible disposal and recycling
• Fire blankets and kitchen fire protection
• Fire extinguisher inspection records
• Multi-site maintenance programmes
• Nationwide service coverage

Conclusion

Fire extinguishers provide important first-aid firefighting protection when they are correctly selected, installed and maintained.

Different extinguishers are designed for different fire risks. Therefore, water, foam, CO₂, powder, wet chemical and specialist extinguishers should never be treated as interchangeable.

The correct provision should be determined through the fire risk assessment and a competent review of the premises. Extinguishers should then be commissioned on site, positioned clearly and inspected regularly.

In addition, professional servicing should normally take place every 12 months. Extended servicing, overhauls, recharging and replacement should be completed at the appropriate intervals and whenever defects are identified.

Most importantly, extinguishers should support—not replace—safe evacuation. Staff should understand the building’s fire procedure, raise the alarm promptly and never place themselves at risk to fight a fire.