CO2 fire extinguishers are canisters full of the stuff – carbon dioxide – but how does a carbon dioxide fire extinguisher work? The fire extinguisher is chock full of carbon dioxide in liquid form, pressurized of course but when the extinguisher is used the CO2 expands in the atmosphere and turns into gas.
Cast your minds back to science class, okay, it may be too long ago so let’s take it one step further. The CO2 gas is heavier than the oxygen in the air so it effectively pushes it out, displacing it from around the fuel which is burning to cause the fire. The fire is extinguished because the oxygen it needs to feed the flames has been replaced by the carbon dioxide gas.
This is the very basic method in which a carbon dioxide extinguisher can fight fires. This type of extinguisher is particularly popular in restaurants because the carbon dioxide quickly disperses without spoiling the food or the cooking equipment.
How To Use A Carbon Dioxide Fire Extinguisher
Direct the CO2 at the base of the fire and move it gradually along the entire area of the flames. This type of fire extinguisher is also effective at tackling fires which involve live electrical equipment so are great for computer servers and similar. The hot plastics could re-ignite though so watch out for that.
A Few Words Of Warning About CO2 Fire Extinguishers
- This type of extinguisher must not be used on chip pan fires – the carbon dioxide will spray the burning oil out of the container and the fire will spread.
- Be very careful when using this type of fire extinguisher in an enclosed space. Remember that the carbon dioxide gas displaces the oxygen in the air, fires need oxygen in order to burn and people need oxygen in order to breathe. As soon as the fire has been contained any enclosed spaces must be well ventilated.
It’s also worth remembering that any type of small, portable fire extinguisher will only hold a small amount of firefighting substance so is really only effective on smaller fires. You should always call the fire brigade for larger fires and to check that even smaller fires have been dealt with properly and are not likely to burst back into life.