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There are 4 categories of fire extinguishers, based on the types of fires. The extinguishers are rated according to how much fire that category can handle. The categories are as follows.
Class A – Extinguishers, which can be used on ordinary combustibles such as paper, wood and plastics. This rating represents the amount of water the fire extinguisher holds and the amount of fire it can handle.
Class B – Extinguishers, which can be used on flammable or combustible liquids such as gas, kerosene or grease. This rating represents the amount of square footage the extinguisher can cover.
Class C – Extinguishers, which can handle electrical equipment such as appliances, wiring and circuit breakers. This rating indicates the extinguisher is non-conductive.
Class D – Extinguishers, which can handle combustible metals.
How it Works
CO2 fire extinguishers are used for class’ B & C fires. This type of fire extinguisher contains a non-flammable gas, and is highly pressurized. The pressure is so intense, that bits of dry ice can shoot out the nozzle. CO2 fire extinguishers don't work very well on class A fires because they may not be able to displace enough oxygen to put the fire out.
Residential Use
CO2 fire extinguishers can be used for commercial or residential use. CO2 extinguishers are the better option for fires in the kitchen or areas of the home with electronics. CO2 is harmless to electrical equipment and are valuable in the home office. The kitchen is the ideal location for this type of extinguisher, because they are most effective on fires caused by the combustion of liquids like grease, oils and solvents.
Commercial Use
CO2 fire extinguishers can be found in chemical labs and restaurants to fight similar fires found in the home kitchen, but on a larger scale.
Tips
Dry chemical extinguishers leave a non-flammable substance on the extinguished material, preventing the possibility of reigniting the material.
By removing the oxygen from the fire, re-ignition is unlikely. CO2 fire extinguishers should be sprayed toward the base of the fire and side to side. The base is the target, to eliminate that main component feeding the fire – the oxygen. If the fire is sprayed at the top of the fire, the risk is great that the fire will be spread.
Ensure you do not hold the nozzle of the CO2 fire extinguisher. This will result in a cold burn. The carbon dioxide cloud cools the fire, while extinguishing the flames.
Cost and Size
A CO2 fire extinguisher costs from $110 - $385. The most common size for residential use is 5 pounds for your home, but can be purchased at 100 pounds for commercial use.
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