CO2 Fire Extinguisher Uses: What Can It Put Out?
A CO2 fire extinguisher uses carbon dioxide to suppress certain types of fires without leaving powder, foam or water residue behind. This makes CO2 extinguishers particularly useful around electrical equipment, computers, machinery and certain flammable liquid fires.
But a CO2 extinguisher is not suitable for every type of fire.
Understanding what a CO2 fire extinguisher is used for, what it cannot extinguish and when to choose CO2 instead of ABE powder, wet chemical or another extinguisher is an important part of fire safety.
In Australia, CO2 extinguishers are commonly used in offices, workshops, electrical areas, commercial premises, laboratories and other locations where electrical equipment or flammable liquids present a fire risk.
What Is a CO2 Fire Extinguisher Used For?
A CO2 fire extinguisher is primarily used for:
Fires involving energised electrical equipment
Certain Class B flammable liquid fires, such as petrol, oil and solvents
Electrical equipment such as computers, switchboards, control panels and machinery
Areas where avoiding powder or liquid residue is important
Fire and Rescue NSW lists carbon dioxide as an extinguisher medium to be considered for fires involving energised electrical equipment and certain flammable liquid fires.
One of the main advantages of CO2 is that it does not leave a powder or liquid residue after discharge.
This can be particularly valuable where fire protection is required around sensitive electrical or electronic equipment.
How Does a CO2 Fire Extinguisher Work?
CO2 extinguishers contain carbon dioxide under pressure. When the extinguisher is discharged, the CO2 is released around the fire.
The carbon dioxide helps suppress combustion by reducing the oxygen available around the flames. The discharge is also very cold, helping to reduce the temperature of the burning area.
Unlike dry chemical powder extinguishers, CO2 does not leave a powder residue.
This makes CO2 useful where cleaning up extinguishing agent could create additional problems for electrical or sensitive equipment.
CO2 Fire Extinguisher for Electrical Fires
One of the best-known uses for a CO2 extinguisher is electrical fire protection.
CO2 extinguishers are commonly used around:
Computers
Servers
Switchboards
Electrical control panels
Motors
Machinery
Office electrical equipment
Workshop equipment
Electrical appliances
Fire and Rescue NSW specifically identifies carbon dioxide as an extinguishing medium for fires involving energised electrical equipment.
The major advantage is that CO2 does not leave the powder residue associated with many dry chemical extinguishers.
However, an extinguisher should only be used if the fire is small enough to tackle safely, the extinguisher is suitable for the fire risk and the person using it has a safe escape route.
If there is any doubt, evacuate and call 000.
Can You Use a CO2 Extinguisher on Computers and Electronics?
Yes. CO2 extinguishers are commonly selected for electrical and electronic equipment because the extinguishing agent does not leave a powder or liquid residue.
This makes them particularly useful in locations such as:
Server rooms
Offices
Computer rooms
Electrical rooms
Workshops
Laboratories
Communications areas
Control rooms
However, CO2 should not be treated as a universal solution for every fire involving electronic equipment. If surrounding materials such as plastic, insulation, paper or other combustibles have caught fire, the fire may require a different extinguishing medium.
Can a CO2 Fire Extinguisher Be Used on Petrol?
Yes. An appropriately rated CO2 extinguisher can be used for certain Class B fires involving flammable liquids, including petrol.
Other examples of Class B fire risks can include:
Diesel
Oils
Solvents
Paints
Thinners
Other flammable liquids
Fire and Rescue NSW lists carbon dioxide among the extinguishing media that may be considered for petroleum-based liquid fires.
For larger or more developed flammable-liquid fires, the appropriate extinguisher type and fire-fighting strategy will depend on the specific risk.
Can a CO2 Extinguisher Be Used on a Gas Fire?
This requires particular caution.
Australian fire-safety guidance identifies Class C fires as fires involving flammable gases, such as LPG and natural gas. Fire and Rescue NSW advises that gas fires should not be extinguished unless the gas supply has first been shut down.
The priority is therefore to isolate the gas supply if this can be done safely.
Do not rely on an extinguisher to solve an ongoing gas leak. If the gas continues to escape, the fire can reignite and create a serious explosion or flash-fire hazard.
Always check the extinguisher's actual rating and follow the manufacturer's instructions.
Can You Use a CO2 Fire Extinguisher on Cooking Oil?
CO2 is not the preferred extinguisher for cooking oil and fat fires.
Commercial cooking-oil and fat fires are classified as Class F fires, and wet chemical extinguishers are specifically designed for this type of hazard.
Fire and Rescue NSW identifies wet chemical as the appropriate extinguishing medium for Class F cooking-oil and fat fires, while listing CO2 as limited.
Never attempt to put out a burning deep fryer by throwing water onto it. Water can cause burning oil to violently spread.
For commercial kitchens and other areas with significant cooking-oil risks, the extinguisher selection should be based on the specific fire hazard and applicable requirements.
Can You Use CO2 on Wood, Paper or Clothing?
CO2 is generally not the preferred extinguisher for Class A fires involving ordinary combustible materials such as:
Wood
Paper
Cardboard
Textiles
Clothing
CO2 may knock down flames temporarily, but it does not provide the same sustained cooling and penetration into porous materials as extinguishing agents designed for Class A fires.
Fire and Rescue NSW identifies water, foam and ABE powder among the extinguishing media used for larger Class A carbonaceous fires, while CO2 is listed as limited for some smaller Class A fires.
For this reason, you should not choose a CO2 extinguisher as your general-purpose extinguisher simply because it is suitable for electrical equipment.
CO2 vs ABE Fire Extinguisher
Choosing between a CO2 extinguisher and an ABE powder extinguisher depends on the fire risks in the location.
Feature | CO2 Extinguisher | ABE Powder Extinguisher |
Electrical fires | Suitable when appropriately rated | Suitable when appropriately rated |
Flammable liquids | Suitable for applicable Class B fires | Suitable |
Class A combustibles | Limited/not preferred | Suitable |
Cooking oils/fats | Not preferred | Check specific rating and application |
Residue | No powder residue | Powder residue |
Sensitive electronics | Advantage where residue is a concern | Powder can contaminate equipment |
General-purpose protection | More limited | More versatile |
For a workplace with significant electrical equipment and little Class A combustible material, CO2 may be an appropriate choice.
For a broader range of fire risks, an appropriately rated ABE powder extinguisher may provide wider coverage.
The correct choice should always be based on the actual fire risk, extinguisher rating and applicable Australian requirements.
Why Are CO2 Extinguishers Used in Server Rooms?
Server rooms contain large amounts of electrical and electronic equipment.
A fire extinguisher that leaves powder or liquid residue can create additional cleanup and equipment-contamination problems.
CO2 has several advantages in this environment:
It leaves no powder residue.
It does not leave a wet extinguishing agent.
It is suitable for appropriately rated electrical fire risks.
It can be used around many types of electrical equipment.
However, fire protection for a server room should not depend solely on a portable extinguisher. Fire detection, electrical safety, emergency procedures and the overall fire protection system are also important.
Where Are CO2 Fire Extinguishers Commonly Used?
CO2 extinguishers can be suitable for locations where electrical equipment or certain flammable liquids present a fire risk.
Common applications include:
Offices
Computers, printers, electrical equipment and power systems can create electrical fire risks.
Workshops
Workshops may contain electrical machinery and flammable liquids.
Server and IT Rooms
CO2 can help avoid powder contamination of sensitive electronic equipment.
Laboratories
Electrical equipment and certain flammable liquids may require suitable clean extinguishing agents.
Electrical Rooms
CO2 can be used for appropriately rated fires involving energised electrical equipment.
Commercial and Industrial Equipment
Machinery, control panels and electrical systems can present specific fire risks requiring suitable extinguishing equipment.
The extinguisher should always be selected according to the specific hazards present.
What Are the Limitations of a CO2 Fire Extinguisher?
CO2 extinguishers have important limitations.
1. They are not a universal extinguisher
CO2 is not the best choice for every fire class.
2. Limited effectiveness on Class A materials
Paper, wood, cardboard and textiles can continue to smoulder after the visible flames have been knocked down.
3. Not the preferred choice for cooking-oil fires
Class F cooking-oil and fat fires require an appropriate extinguisher designed for that hazard.
4. CO2 can be hazardous in confined spaces
Carbon dioxide can displace oxygen. A significant release in a small or poorly ventilated space can create an asphyxiation hazard.
5. The discharge horn becomes extremely cold
The discharge components can become extremely cold during operation. Follow the manufacturer's operating instructions and use the extinguisher by its designated handles.
6. Re-ignition can occur
CO2 may suppress flames without providing sufficient cooling of the underlying fuel. If the source of the fire remains hot, the fire can potentially reignite.
What Size CO2 Fire Extinguisher Do I Need?
CO2 extinguishers are available in different capacities, including 2kg, 3.5kg and 5kg models.
The correct size depends on:
The fire risk
The required fire rating
The location
The amount and type of combustible material
The distance from the potential fire
Applicable Australian requirements
For example, a smaller CO2 extinguisher may be appropriate for a specific electrical risk where a compact unit is required, while larger units can provide greater capacity.
Do not select an extinguisher based only on its kilogram capacity. The fire rating displayed on the extinguisher is an important part of determining whether it is suitable for the intended application.
How to Use a CO2 Fire Extinguisher
Only attempt to use a portable fire extinguisher if the fire is small, you have been trained or are confident in its operation, the extinguisher is suitable and you have a clear escape route.
The basic PASS method is:
Pull the pin or remove the safety mechanism.
Aim the discharge horn toward the base of the fire.
Squeeze the operating handle.
Sweep the discharge across the fire as appropriate.
Fire and Rescue NSW describes PASS as the four basic steps for operating modern portable fire extinguishers.
Never put yourself at risk to fight a fire.
If the fire grows, the extinguisher does not quickly control it, smoke becomes overwhelming or your escape route is threatened, evacuate immediately and call 000.
What Should You Do After Using a CO2 Extinguisher?
A CO2 extinguisher should not simply be returned to its bracket after it has been discharged.
After use:
Leave the area if the fire is not completely controlled.
Call emergency services where appropriate.
Have the extinguisher inspected.
Have it recharged or replaced as required.
Investigate why the fire occurred.
Make sure the fire protection equipment is ready for future use.
Regular inspection and maintenance of fire equipment is an important part of workplace fire safety. Fire and Rescue NSW recommends that businesses ensure installed fire equipment is regularly maintained and suitable for the specific fire risks present.
CO2 Fire Extinguisher FAQs
What is a CO2 fire extinguisher used for?
A CO2 fire extinguisher is commonly used for fires involving energised electrical equipment and certain Class B flammable-liquid fires. It is particularly useful where avoiding powder or liquid residue is important.
Can a CO2 extinguisher be used on an electrical fire?
Yes. An appropriately rated CO2 extinguisher can be used on fires involving energised electrical equipment. Fire and Rescue NSW and SA Metropolitan Fire Service both identify CO2 as suitable for electrical fire risks.
Can a CO2 extinguisher be used on petrol?
Yes. CO2 can be used for applicable Class B flammable-liquid fires, including petrol, provided the extinguisher has the appropriate rating.
Can a CO2 extinguisher be used on cooking oil?
CO2 is not the preferred extinguisher for cooking-oil and fat fires. Class F cooking fires require an appropriate extinguisher, typically wet chemical for commercial cooking applications.
Can a CO2 extinguisher be used on paper or wood?
CO2 is not the preferred extinguisher for Class A fires involving materials such as wood, paper, cardboard and textiles because these materials can continue to smoulder and reignite.
Can a CO2 extinguisher be used on a gas fire?
Gas fires require particular caution. The gas supply should be isolated if this can be done safely. Fire and Rescue NSW advises that gas fires should not be extinguished unless the gas supply has been shut down.
What is the difference between CO2 and ABE fire extinguishers?
CO2 extinguishers are particularly useful for electrical equipment and certain flammable-liquid fires and leave no powder residue. ABE powder extinguishers cover a broader range of fire risks, including Class A, B and applicable electrical risks, but leave powder residue.
Why are CO2 extinguishers used for computers?
CO2 leaves no powder or liquid residue, making it useful around computers, servers and other sensitive electrical equipment where contamination from an extinguishing agent could be a concern.
What size CO2 extinguisher do I need?
The correct size depends on the fire risk, location and required fire rating. Common CO2 extinguisher capacities include 2kg, 3.5kg and 5kg, but kilogram capacity alone should not be used to determine suitability.
How does a CO2 fire extinguisher work?
A CO2 extinguisher releases carbon dioxide under pressure. The gas helps suppress combustion by reducing the oxygen available around the fire, while the cold discharge helps reduce the temperature.
Final Thoughts
A CO2 fire extinguisher is an important fire-safety option for electrical equipment and certain flammable-liquid fire risks, particularly where avoiding powder or liquid residue is important.
However, CO2 is not a universal fire extinguisher.
It is important to understand the difference between:
Electrical fires – CO2 can be appropriate when correctly rated.
Class B flammable liquids – CO2 can be suitable for applicable fires.
Class A materials – CO2 is generally not the preferred choice.
Class C gas fires – the gas supply must be isolated safely before attempting to extinguish the fire.
Class F cooking oils and fats – an appropriate extinguisher such as wet chemical is required for the relevant application.
The most important consideration is not simply choosing a CO2 extinguisher because it is marketed as an “electrical fire extinguisher”. The extinguisher should have the appropriate rating for the actual fire risks in the location.
For workplace fire protection, extinguisher selection and placement should be based on the applicable Australian requirements and the specific hazards present.
This article provides general information only and is not a substitute for professional advice. It is not customised for any individual's specific situation. Always consult with a qualified professional for personalised guidance.
About Fire Products Direct
With years of experience in the Australian fire safety industry, Fire Products Direct is committed to providing expert guidance and high-quality fire protection solutions. We help businesses and homeowners navigate the complexities of fire safety to ensure they have the right protection for their specific needs. Call 02 8313 5404
Fire Products Direct supplies CO2 fire extinguishers in a range of sizes for electrical and other applicable fire risks.
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