What Is a Carbon Dioxide Fire Extinguisher?

Mary McMahon
Mary McMahon

A carbon dioxide (CO2) fire extinguisher is a firefighting tool that is loaded with pressurized carbon dioxide gas. This gas expands very rapidly when a person deploys the device to smother a fire, limiting the fire's supply of oxygen. Many hardware and home supply stores sell carbon dioxide fire extinguishers and it is also possible to install a CO2fire suppression system in a facility where it might be useful.

Carbon dioxide fire extinguishers contain pressurized carbon dioxide gas and can only be used on Class B and C fires.
Carbon dioxide fire extinguishers contain pressurized carbon dioxide gas and can only be used on Class B and C fires.

This type of fire extinguisher is suitable for use on class B and C fires. Class B fires involve flammable liquids such as kerosene, and class C fires include electrical equipment. In a fire involving a flammable liquid, the gas can limit the supply of oxygen to the fire when it expands, putting out the fire. For electrical fires, it does the same thing, and because it is electrically nonconductive, there is a low risk of shock.

Class A fires that involve combustible materials are not safe for a carbon dioxide fire extinguisher. The high-pressure gas can actually scatter the materials and make the fire larger. In addition, it might not suppress the oxygen supply long enough to put out the fire. The materials could smolder, and when the gas dissipates, the fire might flare up again. Fire extinguishers should have rating indications to indicate the kinds of fires on which they can be used and it can be helpful for a person to get familiar with the ratings in preparation for a fire.

A typical carbon dioxide fire extinguisher has a hard, horn-shaped nozzle to direct the flow of gas. The operator should be careful, because this gas is extremely cold when it vents from the extinguisher. Chunks of dry ice can form around the rim, and people could develop injuries if they handle the nozzle. It also is potentially dangerous to use such devices in areas that don't have a supply of oxygen for the operator, because he or she could suffocate while putting out the fire.

One advantage of the carbon dioxide fire extinguisher is that it does not leave residue. The gas evaporates and clears the area. This can be important in a location that has expensive electronic equipment, because other suppression devices might damage the equipment. It also can be helpful for other types of fires, after which cleanup might be a concern. A carbon dioxide fire extinguisher should be regularly inspected to make sure that it works, and it can be refilled after use.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


My little brother decided to play with the fire extinguisher we have in our kitchen and sprayed it everywhere, including his face. He had to go to the hospital and they rinsed his eyes with a special solution.

Apparently, it can be very dangerous if the foam from the extinguisher gets into the eyes and mouth because it has some type of chemical in it.


@donasmrs-- It's a great idea to keep a fire extinguisher in the car. I think quite a few people die every year from car fires. I'm not sure which is the best type to get but it should be either class B or C.

I think class B is for petrol and class C is for lpg (gas) which is more common in Europe. And then there is glass A which is good for rubber. There is also some kind of standard that carbon dioxide fire extinguishers have to be built up to and a symbol of the standard should be on the bottle.


Is anyone carrying a portable carbon dioxide fire extinguisher in their car?

I'm thinking of getting one.

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