What Is a Laboratory Fire Extinguisher? Types and Selection

A laboratory fire extinguisher is a portable first-response device selected for the specific fire hazards present in a laboratory. It is designed to control a small fire during its earliest stage, provided the user is trained, the correct extinguisher is available and a safe escape route remains open.

There is no single extinguisher that is suitable for every laboratory fire. Laboratories may contain flammable solvents, combustible materials, electrical equipment, compressed gases, reactive metals and lithium-ion batteries. Each hazard can require a different extinguishing agent.

Using the wrong extinguisher can spread burning liquid, react dangerously with chemicals, damage sensitive instruments or expose the user to electric shock. This guide explains the main fire classes, compares common extinguisher types and outlines how to select suitable fire protection for a laboratory.

This article provides general information using Australian fire classifications and standards. Fire class terminology differs between countries. Extinguisher selection, installation and servicing should be completed or verified by a qualified fire protection professional.

Laboratory Fire Extinguisher Definition

A laboratory fire extinguisher is not a separate category of extinguisher. It is a compliant portable extinguisher selected and positioned according to the fire risks within a particular laboratory.

A laboratory may require more than one type. For example:

• A carbon dioxide extinguisher may be provided near sensitive electrical equipment.
• An appropriate Class B extinguisher may be required where flammable solvents are handled.
• A Class D extinguisher may be required for laboratories using combustible metals.
• An A-rated extinguisher may be installed for paper, packaging, plastics and other ordinary combustibles.

Extinguishers are intended for small, early-stage fires. They are not a substitute for fire alarms, evacuation procedures, emergency showers, automatic suppression systems or trained emergency responders.

If there is any doubt about personal safety, evacuate the area, close doors where safe to do so and call emergency services on Triple Zero (000).

Fire Classes in Australian Laboratories

Fire extinguishers are classified according to the fuel or hazard they are designed to control.

Australian guidance commonly uses the notation (E) for fires involving energised electrical equipment. Electricity is not itself a fuel. Once the power has been safely isolated, the remaining fire is classified according to the material that continues to burn.

Other countries use different classifications. For example, North American systems use Class C for energised electrical equipment, while Australia uses Class C for flammable gases. Always follow the classifications printed on the extinguisher and applicable in your country.

Types of Laboratory Fire Extinguishers

Water Fire Extinguishers

Water extinguishers cool burning material and are primarily intended for Class A fires.

Suitable laboratory materials can include:

• Paper and cardboard
• Wood
• Cloth
• Some plastics
• General combustible waste

Water extinguishers must not be used on flammable liquids, flammable gases, combustible metals or energised electrical equipment. Water can spread a burning solvent, conduct electricity or react violently with substances such as sodium, potassium and some metal hydrides.

Water extinguishers are identified in Australia by an all-red cylinder without a coloured contents band.

Foam Fire Extinguishers

Foam extinguishers are generally used on Class A and Class B fires. The foam can cool the material and form a layer over a flammable liquid, helping suppress vapour and reduce contact with oxygen.

Potential laboratory applications include:

• Combustible solids
• Certain hydrocarbon solvents
• Oils
• Paints and similar flammable liquids

A standard foam extinguisher is not suitable for every laboratory solvent. Polar solvents such as alcohols can break down some conventional foams, so an alcohol-resistant formulation may be required.

Foam should not be used on energised electrical equipment unless the extinguisher is specifically tested and marked for that application. Compatibility must be confirmed using the extinguisher rating, manufacturer instructions and site risk assessment.

Foam extinguishers traditionally have a blue identification band in Australia.

Carbon Dioxide Fire Extinguishers

Carbon dioxide extinguishers discharge non-conductive CO₂ gas that reduces the oxygen available around the flame. They leave no powder, foam or water residue.

CO₂ extinguishers are commonly selected for:

• Energised electrical equipment
• Laboratory instruments
• Computers and control systems
• Small Class B flammable-liquid fires
• Areas where residue could damage sensitive equipment

The clean discharge makes CO₂ attractive for laboratories, but it has important limitations. It provides little cooling, so hot materials may reignite after the gas disperses. It also has limited effectiveness on deep-seated Class A fires.

CO₂ can displace breathable air and should be used cautiously in small or poorly ventilated rooms. The discharge is extremely cold and can cause cold burns if the horn or metal components are handled incorrectly. The discharge pressure can also scatter lightweight materials or spill containers.

CO₂ extinguishers have a black identification band in Australia.

Dry Chemical Powder Fire Extinguishers

Dry chemical powder extinguishers interrupt the chemical reaction that sustains combustion. They provide broad fire coverage and are commonly supplied in ABE or BE formulations.

ABE powder extinguishers can be suitable for:

• Class A combustible solids
• Class B flammable liquids
• Class C flammable gases
• Fires involving energised electrical equipment

BE powder extinguishers do not provide Class A coverage but may be rated for flammable liquids, gases and electrical hazards.

Dry chemical powder is effective across several common hazards, but it can create significant contamination. The powder spreads widely, obscures visibility and can enter instruments, ventilation systems and electronic equipment. Cleaning after discharge can be difficult and expensive.

In laboratories containing sensitive analytical instruments, the contamination risk should be considered alongside the extinguisher's broad fire rating.

Dry chemical powder extinguishers have a white identification band in Australia.

Wet Chemical Fire Extinguishers

Wet chemical extinguishers are designed primarily for Class F fires involving high-temperature cooking oils and fats. Some are also rated for Class A materials.

They are normally installed in:

• Commercial kitchens
• Food research laboratories with cooking equipment
• Pilot plants using heated oils
• Staff kitchens with deep fryers

A wet chemical extinguisher is not normally the primary choice for chemical laboratories, flammable-solvent fires or energised electrical equipment.

Wet chemical extinguishers traditionally have an oatmeal-coloured identification band in Australia.

Class D Metal Fire Extinguishers

Class D extinguishers contain specialised dry agents for combustible metal fires. Unlike general-purpose powder extinguishers, the agent must be compatible with the particular metal involved.

Class D risks may include:

• Sodium
• Potassium
• Lithium metal
• Magnesium
• Aluminium powder
• Titanium
• Zirconium
• Metal hydrides and certain organometallic reagents

There is no universal Class D extinguishing agent for every combustible metal. An agent suitable for magnesium may not be suitable for lithium, sodium or another reactive material.

Water, foam, CO₂ and standard ABE powder can be ineffective or dangerous on some metal fires. Water may trigger a violent reaction, while CO₂ can react with certain burning metals.

Laboratories working with combustible metals should identify the correct agent from the chemical safety data sheet, supplier guidance and site-specific emergency plan.

Vaporising-Liquid Fire Extinguishers

Vaporising-liquid extinguishers use a clean, non-conductive agent and may be rated for Class A, Class B and electrical hazards, depending on the product.

They leave little or no residue and may be considered where sensitive electronic or analytical equipment is present. Only compliant, currently approved products should be used. Older halon or BCF extinguishers have been withdrawn from general use because of environmental and safety concerns.

In Australia, approved vaporising-liquid extinguishers have traditionally used a yellow identification band.

Fire Extinguisher Comparison

The fire classes shown above are general. The exact rating printed on the extinguisher always takes priority.

Which Fire Extinguisher Is Best for a Laboratory?

There is no single best extinguisher for every laboratory. Selection depends on the substances, instruments and processes in each room.

Flammable-Solvent Laboratories

Laboratories using ethanol, acetone, hexane, methanol or other flammable liquids require suitable Class B coverage.

Possible choices include foam, CO₂ or dry chemical powder, depending on:

• The solvent involved
• The quantity stored or used
• Whether the solvent is water-miscible
• The presence of energised electrical equipment
• Room ventilation
• Spill containment
• The potential impact of extinguisher residue

For substantial flammable-liquid quantities, a portable extinguisher may be only one part of the required fire protection system. Correct storage in flammable liquid storage cabinets reduces the likelihood of a fire in the first place.

Electrical and Instrument Laboratories

CO₂ is frequently selected around computers, balances, analysers, power supplies and other electrical equipment because it is non-conductive and leaves no residue.

However, CO₂ may not control burning plastic, insulation or furnishings after the power is isolated. Separate Class A coverage may therefore be required.

An extinguisher should not be selected solely to protect the equipment from residue. The first priority is protecting people and controlling the identified fire hazard.

Laboratories Using Combustible Metals

Laboratories handling sodium, potassium, magnesium, lithium metal or reactive metal powders require a metal-specific assessment.

The laboratory should have:

• A compatible Class D agent
• Clearly labelled containers
• Documented emergency procedures
• Appropriate spill-control materials
• Staff trained for the specific chemical
• Suitable segregation from water-based extinguishers where misuse is possible

The safety data sheet should be reviewed, but extinguisher selection should also be confirmed with the chemical supplier and a qualified fire protection professional.

Laboratories Using Flammable Gases

For a gas fire, stopping the fuel supply is normally critical. Extinguishing the flame while gas continues to escape can create an unignited flammable cloud and a greater explosion risk.

Only trained personnel should attempt to isolate a gas supply when it is safe to do so. Otherwise, evacuate the area and contact emergency services. Gas detection equipment can provide early warning of a leak before ignition.

Biological and General Teaching Laboratories

A general teaching or biological laboratory may contain Class A materials, small quantities of flammable liquids and electrical equipment.

It may therefore require a combination of:

• A suitable Class A extinguisher
• Class B coverage for flammable liquids
• An extinguisher suitable for energised electrical equipment

The quantity and type of chemicals used should still be reviewed. A general-purpose extinguisher should not be assumed to cover every experiment.

What About Lithium-Ion Battery Fires?

Lithium-ion batteries can enter thermal runaway, producing intense heat, flammable gases, toxic decomposition products and repeated reignition. A battery fire is different from a fire involving bulk lithium metal.

The correct response depends on:

• Battery chemistry
• Battery size and energy capacity
• Number of cells
• Whether the battery is contained inside equipment
• Charging and storage arrangements
• Ventilation
• Manufacturer emergency instructions
• Local fire authority guidance

Products marketed specifically for lithium-ion battery fires are available, but there is no universal portable extinguisher solution for every battery size and configuration. Large battery packs, storage cabinets and charging areas may require engineered detection, isolation and suppression systems.

Do not assume that a Class D extinguisher intended for lithium metal is automatically suitable for a lithium-ion battery fire. These hazards involve different materials and fire behaviour.

Battery fire planning should be completed with a competent fire safety specialist and should address evacuation, toxic smoke, cooling, reignition and damaged-battery quarantine.

How to Choose a Laboratory Fire Extinguisher

1. Complete a Fire Risk Assessment

Start by identifying every combustible, flammable, reactive and electrically powered material in the laboratory.

Review:

• Chemical inventories
• Safety data sheets
• Flammable-liquid storage
• Gas cylinders and gas lines
• Combustible metals
• Pyrophoric chemicals
• Oxidising agents
• Heating equipment
• Electrical instruments
• Battery charging and storage
• Waste accumulation

The assessment should consider both normal operation and foreseeable incidents.

2. Identify Every Relevant Fire Class

A laboratory commonly contains more than one fire class. Selecting an extinguisher only for the most obvious hazard can leave other risks uncovered.

For example, a solvent laboratory may have a Class B risk from liquids, an electrical hazard from instruments and a Class A risk from packaging and furnishings.

3. Check Chemical Compatibility

Confirm that the extinguishing agent will not react with the chemicals present. Water-reactive substances, combustible metals, strong oxidisers and unusual solvents require particular attention.

Never assume that a broad extinguisher rating guarantees compatibility with every chemical in that class.

4. Consider People and Equipment

An extinguisher must control the hazard without creating an unacceptable secondary risk.

Consider:

• Toxicity and inhalation hazards
• Room size and ventilation
• Visibility during discharge
• Cold-discharge hazards
• Residue on sensitive instruments
• Decontamination requirements
• Ease of operation
• Staff capability and training

5. Select the Required Rating and Capacity

Extinguisher labels show both the fire classification and performance rating. The rating indicates the size of test fire the extinguisher has successfully controlled.

A physically larger extinguisher does not automatically mean it is the correct choice. It must provide the appropriate fire rating while remaining accessible and manageable for intended users.

A qualified fire protection professional should determine the necessary rating, capacity and number of extinguishers.

6. Position the Extinguisher Correctly

Australian Standard AS 2444 covers the selection and location of portable fire extinguishers and fire blankets.

Extinguishers should be:

• Clearly visible
• Properly signed
• Readily accessible
• Mounted securely
• Positioned along an escape route where appropriate
• Protected from obstruction, corrosion and physical damage
• Located so a user is not forced to move towards a fire to retrieve one

Do not place the only extinguisher immediately beside the most likely ignition source. A fire could make it impossible to reach.

7. Arrange Professional Review and Installation

The final selection should be reviewed by a competent fire protection professional who understands the laboratory's chemical hazards, building requirements and applicable legislation.

Extinguishers should comply with applicable Australian Standards, including AS/NZS 1841.1 for portable extinguisher requirements.

When Should You Use a Fire Extinguisher?

A portable extinguisher should only be considered when:

• The fire is small and has not spread
• The correct extinguisher is immediately available
• The user has been trained
• The alarm has been raised
• Emergency assistance has been called
• Other people are evacuating or have evacuated
• Smoke and heat do not threaten the user
• A clear escape route remains behind the user
• The chemical and extinguisher are known to be compatible

Do not attempt to fight the fire if:

• The material is unknown
• Smoke is rapidly filling the room
• The fire involves a gas cylinder or pressurised vessel
• The fire involves reactive metals and the correct agent is unavailable
• The fire is spreading beyond its original container
• The extinguisher is not controlling the fire immediately
• The fire is between you and the exit
• You have not been trained
• You feel unsafe for any reason

Evacuation takes priority over equipment or property.

How to Use a Fire Extinguisher

The PASS method is commonly used to remember the basic operating sequence:

1. Pull the safety pin.
2. Aim the nozzle at the base of the fire.
3. Squeeze the operating handle.
4. Sweep the nozzle from side to side.

Always follow the instructions printed on the extinguisher. Discharge characteristics, operating distances and techniques differ between extinguisher types.

Keep the exit behind you throughout the attempt. If the fire does not reduce immediately, stop, evacuate and close the door where safe to do so.

Never turn your back on the fire while leaving, and do not re-enter the area after evacuation.

Common Mistakes When Selecting Laboratory Fire Extinguishers

Most Common Mistake

Assuming that one general-purpose extinguisher can safely control every laboratory fire. ABE powder provides broad coverage, but it is not suitable for every reactive chemical, combustible metal or specialist hazard.

Other common mistakes include:

• Using water on a solvent fire: water can spread the burning liquid and increase the affected area.
• Using water near energised equipment: this creates an electric-shock risk.
• Using a standard extinguisher on combustible metals: water, CO₂, foam and general-purpose powder may react dangerously or be ineffective.
• Using the wrong Class D agent: different metals can require different specialised powders.
• Selecting CO₂ for every laboratory: CO₂ leaves no residue but may not cool the fuel sufficiently to prevent reignition.
• Ignoring extinguisher residue: dry powder can contaminate instruments, experiments and ventilation systems.
• Placing the extinguisher too close to the hazard: the fire may block access to it.
• Blocking the extinguisher: boxes, trolleys or furniture can delay access during an emergency.
• Failing to train staff: an extinguisher is of limited value if personnel cannot identify or operate it safely.
• Extinguishing a gas flame without stopping the leak: escaping unburnt gas can create an explosion hazard.
• Assuming a lithium-metal extinguisher covers lithium-ion batteries: these are different fire hazards requiring separate assessment.

Fire Blankets in Laboratories

A fire blanket is not a substitute for a correctly selected extinguisher. It may be useful for smothering a small, contained fire where the laboratory's procedures identify it as appropriate.

Fire blankets should be:

• Compliant with the applicable standard
• Clearly marked
• Mounted in an accessible location
• Inspected and maintained
• Included in staff training

For burning clothing, laboratories should follow their documented emergency procedure. A safety shower is commonly the preferred laboratory control because it can extinguish flames while cooling the casualty. Staff should not improvise with a fire blanket unless trained and directed by the site's procedure.

Inspection, Servicing and Replacement

Fire extinguishers require routine inspection and professional servicing. An extinguisher can appear undamaged while having lost pressure or developed internal problems.

Routine visual checks should confirm:

• The extinguisher is in its designated position
• Access is unobstructed
• Signage is visible
• The safety pin and tamper seal are intact
• The pressure indicator is within the operating range, where fitted
• The cylinder is free from corrosion and physical damage
• The hose or nozzle is unobstructed
• The operating instructions are legible
• The service tag or record is current

Servicing should be performed by an appropriately qualified technician in accordance with applicable regulations, Australian Standards and manufacturer instructions.

Any extinguisher that has been discharged, even briefly, should be removed from service and professionally inspected, refilled or replaced. Do not return a partially discharged extinguisher to its mounting point.

Frequently Asked Questions

What is the best fire extinguisher for a laboratory?

There is no single best extinguisher for every laboratory. The correct selection depends on the chemicals, combustible materials, gases, electrical equipment, reactive metals and batteries present. Many laboratories require more than one extinguisher type. A professional fire risk assessment should determine the required classifications, ratings and locations.

Is a CO₂ extinguisher suitable for a laboratory?

CO₂ extinguishers are commonly used around energised electrical equipment and sensitive instruments because they are non-conductive and leave no residue. They can also have limited Class B applications. However, CO₂ provides little cooling and may allow combustible solids or hot materials to reignite. It may need to be installed alongside another extinguisher that provides suitable Class A or Class B coverage.

Is an ABE dry powder extinguisher suitable for a laboratory?

ABE powder provides broad coverage for ordinary combustibles, flammable liquids, flammable gases and energised electrical equipment. It can therefore be useful in many general environments. Its powder residue can extensively contaminate analytical instruments, electronics, experiments and ventilation systems. It is also not a substitute for a metal-specific Class D extinguisher.

Which extinguisher should be used for flammable solvents?

A Class B-rated extinguisher is generally required for flammable-liquid fires. Depending on the solvent and site conditions, the selected extinguisher may use foam, CO₂, dry chemical powder or another approved agent. The solvent's properties, quantity, water miscibility and proximity to electrical equipment must be considered. Check the safety data sheet and obtain professional advice.

Which extinguisher should be used for sodium or potassium?

Sodium and potassium require a compatible Class D extinguishing agent. Water, foam and CO₂ can react dangerously with these metals. The extinguishing powder must be specifically approved for the metal involved. Confirm the agent with the chemical supplier and a qualified fire safety professional.

Can water be used on a laboratory fire?

Water can be used only when the extinguisher is rated for the burning material and no incompatible chemical or electrical hazard is present. It must not be used on flammable liquids, energised electrical equipment, combustible metals or water-reactive chemicals.

Can a fire extinguisher be used after a small discharge?

No. Once an extinguisher has been discharged, even for a short time, it should be removed from service and inspected by a competent technician. It may have lost pressure or contain insufficient agent for another incident.

How often should laboratory fire extinguishers be serviced?

Inspection and servicing intervals depend on applicable legislation, Australian Standards, building requirements and extinguisher type. Commercial laboratory extinguishers should be maintained under a documented programme by a qualified fire protection provider. Staff should also conduct routine visual checks and report damage, missing seals, pressure problems or blocked access immediately.

Where should a laboratory fire extinguisher be located?

It should be visible, accessible and positioned so the user can reach it without moving towards the fire. Extinguishers are commonly located along escape routes and near, but not directly beside, identified hazards. The final location and distribution should comply with AS 2444 and be determined by a qualified fire protection professional.

Are fire extinguishers enough to protect a laboratory?

No. Fire extinguishers are only one element of laboratory fire safety. A complete system can include:

• Chemical storage and segregation
• Flammable-liquid cabinets
• Gas detection and isolation
• Fire alarms
• Automatic suppression
• Safety showers
• Fire blankets
• Emergency exits
• Spill-control materials
• Staff training and PPE
• Emergency response procedures

Preventing a fire and enabling rapid evacuation are more important than relying on portable extinguishers alone.

Australian Standards and Guidance

Laboratory fire protection should be assessed against current regulatory and building requirements. Relevant Australian references include:

• AS 2444:2001, Portable fire extinguishers and fire blankets: Selection and location
• AS/NZS 1841.1, Portable fire extinguishers: General requirements
• AS 1851, Routine service of fire protection systems and equipment
• AS/NZS 3504, Fire blankets
• Queensland Fire Department fire extinguisher guidance

Requirements can vary according to the state or territory, building classification, chemical inventory and type of laboratory.

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Need Help Improving Laboratory Fire Safety?

Selecting laboratory fire protection begins with understanding the chemicals, equipment and processes used in each area.

LabFriend can assist with laboratory safety products, chemical storage, spill control and personal protective equipment. Selection, installation and servicing of fire extinguishers should be completed by an accredited fire protection provider following a site-specific assessment.