Understanding the fire triangle, oxygen, fuel, and heat, is fundamental to fire safety. CO2 fire extinguishers work by displacing oxygen around flames, suffocating the fire and preventing combustion. These are the extinguishers of choice for electrical fires and Class B liquid fires involving flammable liquids.
Avoid using them on Classes A (solid combustibles like wood or paper), Class C (Flammable gases), Class D (special metals), cooking oil, or fat fires. In confined spaces or small rooms, CO2 gas becomes poisonous at 4% concentration and deadly at 8%, creating breathing hazards. These gas fire extinguisher units leave no residue, perfect for sensitive equipment in commercial fire safety and industrial environments. Only tackle small fires before you evacuate and call the fire and rescue service.
What CO2 Extinguishers Actually Are
Carbon dioxide exists in liquid form under high pressure within the extinguisher, transforming into gas when discharged through the handle is squeezed. The rapidly expanding CO2 gas creates a cold fog that smothers flames instantly. I’ve noticed the hard horn and lack of pressure gauge make these Carbon dioxide extinguishers filled with non-flammable carbon dioxide gas quite distinctive.
When the extinguisher releases this stored liquid, it’s created under pressure and becomes highly pressurised gas inside the canister. During discharge, liquid CO2 will depressurise into gas as you spray it on the fire. The extreme pressure means bits of dry ice might shoot out from the horn when discharged, which caught me off guard during my first training session.
The Science Behind CO2 Fire Suppression
Understanding the fire triangle principle, oxygen, fuel, and heat help explain why removing even one element will extinguish the fire. CO2 fire extinguishers excel at displacing oxygen near the fire, suffocating it while preventing combustion. Unlike water or foam extinguishers, these don’t cool the fire effectively, making them ineffective on flammable solids and Class A solid combustibles. The CO2 extinguisher works by replacing oxygen around flames with carbon dioxide, so the fire cannot burn.
When discharged, it releases carbon dioxide gas under high pressure. The CO2 gas emerges at great speed, looking like dry ice. This cloud of CO2 reduces oxygen in the air and smothers the fire. The rapid expansion creates an extreme drop in temperature, helping cool flammable liquids and electrical equipment, though freeze-burn from gas touching skin is possible. Spraying CO2 displaces the oxygen, suffocating the fire to suppress it. Proper fire alarm installation in these zones adds an additional layer of safety and ensures faster emergency response.
Optimal Locations for CO2 Extinguishers
Any premises with live electrical fire risk need these: Offices, Shops, Schools, and Hospitals top the list. Areas with electrical office equipment benefit from pairing CO2 and Foam extinguishers for internal environment coverage of most fire risks.
Specific places require CO2 extinguishers per fire safety regulations, locations with electrical equipment like Laboratories, Casinos, Server rooms, Mechanical rooms, and Universities. Since they handle Class B fires, they’re also ideal for storage areas with flammable liquids such as petrol, diesel, and paint. I’ve installed them in environments with electrical equipment and flammable liquids, including offices, server rooms, and industrial settings.
Appropriate Fire Classes for CO2 Extinguishers
Class B Fires: Flammable Liquids
I’ve seen CO2 extinguishers tackle Class B fires beautifully! They’re certified for flammable liquids like petrol, diesel, gasoline, oil, alcohols, solvents, paint, oil-based paints, lacquers, and tars. The carbon dioxide works by displacing oxygen and eliminating the fuel source without leaving residue on surfaces. Honestly, this smother technique beats using water any day!
Class C Fires: Electrical Equipment
Here’s where these shine! Class C fires involve energised electrical equipment, such as wiring, appliances, circuit breakers, power panels, electrical sockets, computers, generators, Computer equipment, and Electrical appliances. Using water on these fires risks electrical shock and damage to equipment. CO₂ extinguishers are perfect because carbon dioxide is a non-conductive extinguishing agent, preventing electrocution and short-circuiting.
What CO2 Cannot Handle?
Let me be straight with you, CO2 extinguishers aren’t for everything! Avoid using them on cooking oils, fats, chip pan fires (class F fires), Wood, Paper, Textiles, Fat from deep fat fryers or chip pans, and Cooking oils. Also, skip lithium rechargeable batteries. These fires need different solutions entirely.
Why CO2 Works for Electrical and Liquid Fires
From my experience, electrical fires from live cables and Class B liquid fires are where CO2 truly excels. The flames get smothered without residue, protecting sensitive electrical equipment. CO2 extinguishers handle live electrical situations and flammable liquid scenarios like paraffin spills perfectly because they’re non-conductive and leave no mess behind!
Step-by-Step Operating Instructions
Before You Begin
Handheld fire extinguishers only work on small fires before they’re established. If the fire looks too big, honestly, just escape to safety! Use the extinguisher to aid escape if needed, follow fire services advice to get out and stay out. First, confirm it’s the correct type for your class of fire. Always ensure a smoke alarm is active to provide early warning before the fire spreads.
Carrying the Extinguisher Safely
Never run when carrying! Keep fingers around the nozzle without squeezing the trigger—the pin stays in place at this point. Walk calmly to a suitable distance from the fire. This isn’t a movie scene; controlled movements keep you safer than rushing in heroically!
Positioning Yourself Correctly
Here’s crucial advice: always position yourself between the fire and your escape route. Never let the fire block that escape route! If your extinguisher has a foldable horn, unfold it to about 45o to 60o ° before discharge. Do this prep work before starting anything else!
Removing the Safety Pin
Remove the pin while holding only the trigger; this is super important! Never touch the horn at this stage because it gets dangerously cold. Make sure no persons are potentially in the path of discharge. I always do a quick visual check before proceeding with this step.
The Discharge Technique
Aim the horn at the base of the fire and squeeze the trigger for a short, rapid burst of discharge. Then stop and inspect. Is the fire out? If not, repeat those short, rapid bursts until you’re confident the fire is extinguished. Smart technique saves precious seconds!
Understanding Discharge Time
The discharge time of a CO2 extinguisher weighing 5lkg is just 10 seconds total! By doing short bursts, you’re maximising those 10n seconds effectively. Even if you only used 2 seconds or 3 seconds of discharge, the unit still needs professional attention before reuse.
Post-Discharge Precautions
The horn stays freezer cold after use. Seriously, don’t touch it! Never return the extinguisher to service without having it recharged and serviced by a professional technician. This applies even if you barely used it. Safety protocols exist for good reasons, trust me on this!
Breaking the Tamper Seal
Pull the safety pin to break the tamper seal. Never hold the horn unless it’s specifically a frost-free horn, as it becomes extremely cold and causes severe frost burns. Only purchase CO2 extinguishers with frost-free horn protection. This feature really matters during emergencies!
Confined Space Warning
Don’t use CO2 extinguishers in a confined space, this is critical! Always remove the safety pin to break the anti-tamper seal and stand well back from the fire. Avoid holding the extinguisher by the horn at any point. Maintain that safe distance throughout the operation!
Sweeping Motion Technique
Aim the horn at the base of the fire and move the jet of CO2 backwards and forwards in sweeping motions. For Electrical fires, Switch off the electrical item if it’s safe to do so. For Liquid fires, avoid splashing the burning liquid onto nearby areas.
The PASS Method Application
When using a CO₂ extinguisher, Pull the safety pin which breaks the seal and prepares the extinguisher. Aim at the base of the fire, Direct the nozzle toward the lowest part of the flames, not the smoke. Squeeze the handle and Press the lever to release the carbon dioxide discharge.
Side-to-Side Sweeping
Sweep side to side, Move the nozzle in a controlled motion across the fire until extinguished. Since CO₂ extinguishers work by displacing oxygen, avoid prolonged use in enclosed areas without ventilation. Keep that nozzle moving side to side at the base continuously until you’re done!
Using the ABC Fire Extinguisher Method
Just like a typical ABC fire extinguisher, it’s important to operate the CO2 extinguisher using the P.A.S.S. Method. You can safely use a CO2 extinguisher on small, contained fires only. If the fire is in an enclosed space, skip CO2 extinguishers entirely due to possible asphyxiation.
Understanding Poison Risks
Carbon dioxide is poisonous at a concentration of 4%, that’s lower than you’d think! Instructions for using a CO2 fire extinguisher appear on the side of the canister, though it’s wise to familiarise yourself beforehand. Don’t wait for an emergency to read these directions!
Aiming at the Source
Remove the safety pin, then aim the CO2 extinguisher’s hose at the base of the fire; this targets the source of the fire effectively. Squeeze the lever on the extinguisher and make sweeping movements with the extinguisher’s hose while aiming at the fire’s base continuously.
Handling the Hose Correctly
Always hold the hose at the base, never the nozzle opening! When freezing CO2 gas is discharged, it causes serious freeze-burn on the skin. Remember that CO2 extinguishers discharge quickly, so they should only be used on small fires that can be rapidly contained. Speed matters here!
Benefits of CO2 Fire Suppression
Clean Extinguishing Agent: Carbon dioxide leaves absolutely no residue behind, this is my favourite feature! It’s the preferred choice for areas with sensitive electronic equipment, laboratories, and server rooms. Unlike aqueous film-forming foam or wet chemical extinguishers, CO₂ leaves no oil-based or powdery residue, making cleanup incredibly easy while preventing damage to your sensitive equipment.
Non-Conductive Properties: CO2 extinguishers are completely non-conductive, making them genuinely safe for electrical fires. Since CO₂ as a gas won’t conduct electricity, it’s a safe option for electrical fires in confined spaces or near delicate equipment. You can use them confidently around live circuits without worrying about electrocution risks!
No Damage to Materials: Here’s what impresses me most: CO2 doesn’t react with materials or leave behind corrosive substances, making it suitable for various fire types. After the fire is extinguished, there’s literally no residue. This means no damage to your expensive electronic equipment, unlike a typical ABC extinguisher with powder that’s corrosive and messy.
Rapid Action and Effectiveness: Rapid Action means Carbon dioxide extinguishers work quickly, limiting fire spread and potential damage. They’re extremely effective on electrical fires and are Effective against flammable liquids too! CO₂ extinguishers handle class B fires, including those fueled by flammable gases, oils, and other liquid fire hazards. The speed of suppression genuinely saves property!
Environmentally Friendly Solution: Being Environmentally Friendly, CO2 is a natural component of the atmosphere and doesn’t contribute to ozone depletion. It causes no environmental harm when released. When a CO2 extinguisher discharges gas, the CO2 gas will dissipate into the atmosphere without a trace, guilt-free fire suppression!
Understanding the Limitations
Limited Cooling Effect means CO2 extinguishers don’t provide long-lasting cooling like other extinguisher types, requiring proper fire suppression to prevent re-ignition. Cold Burns from Direct contact with released CO2 gas cause cold burns, the horn gets incredibly cold, and if a user were to touch the horn, they’d suffer freeze-burns on their skin.
You must never touch the horn during use or afterwards. They’re less environmentally friendly than other types of extinguishers and replace oxygen in the air with CO2, creating a risk of asphyxiation in confined spaces.
Conclusion
Knowing how to properly use a CO2 fire extinguisher can make a critical difference during an emergency. These extinguishers are ideal for electrical and Class B liquid fires, providing fast, clean suppression without residue or damage to sensitive equipment. However, users must be aware of their limitations, especially the risk of asphyxiation in confined spaces. Regular maintenance and training ensure readiness when every second counts. Protect your property, staff, and assets with trusted fire safety solutions.
Visit K Force Security to explore certified CO2 extinguishers and expert fire protection services tailored to your needs.