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A guide to CO2 extinguishers

CO2 fire extinguishers contain pure carbon dioxide and are used mainly on fires involving live electrical equipment or those involving flammable liquids. In this handy guide, we explain all about how this type of extinguisher works, when it should and shouldn’t be used and which premises would benefit from one.

Which type of fire should a CO2 extinguisher be used on?
This type of extinguisher is the only one recommended for use on fires that have been started through faults in live electrical equipment. Carbon dioxide is safe to use on electrical equipment because the gas is non-conductive and the residue it leaves behind won’t damage electrical equipment or machinery. In the hands of a trained user a CO2 unit could be used on a class B fire  (flammable liquids like petrol or oil) but they should never be used on cooking fires because its powerful discharge could easily splash burning fat and fan the fire. There is also still the risk of spreading hot liquid with the added danger of re ignition if the hot liquid reignites when the CO2 empties, circa 14 seconds. They’re not deemed suitable for Class A fires (flammable solids) either.

How does a CO2 extinguisher work?
Carbon dioxide is stored in the canister in liquid form. Once released into the air, it suffocates the fire, starving it of oxygen. This ensures the fire no longer burns and the flames don’t spread. 

How is a CO2 extinguisher identified?
The canister has a red body and a black banner running along the top section, which labels it CO2. It has a horn-like black nozzle.

Where is a CO2 extinguisher most suitable for use?
This type of extinguisher is most suited to settings with electrical fire risk. Offices, schools and hospitals would benefit from having them on site because of the volume of electrical equipment present in the building.

How to use a CO2 extinguisher
Always check the safety pin first. It shouldn’t be bent or appear tampered with in any way. Taking care not to hold the horn – it becomes very cold during use and could lead to severe frost burns – remove the safety pin to break the seal. Aim the horn towards the base of the fire and sweep it from side to side until the fire is extinguished.
Always keep an eye on the area in case the fire re-ignites.

Think this type of extinguisher is suitable for your premises? View CheckFire’s extensive range of CO2 extinguishers now. Alternatively, download our simple-view extinguisher guide.


The content of the CheckFire blog is for general information purposes only. While we make every effort to ensure accuracy at the time of publication, under no circumstances should it be considered professional advice. Any reliance you place on the information is at your own risk. Always seek the advice of a fire professional for your particular circumstances and requirements.
  • by Toria Jones

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