Shopping For a Fire Extinguisher

Fire extinguishers are a valuable tool to have in the home, especially when it comes to putting out small fires before they spread. Most fire departments recommend that households have at least one fire extinguisher and that everyone know how to use it. When shopping for a fire extinguisher, you’ll need to consider what kind of fires the extinguisher will fight and whether you want it to be portable or stationary. The best fire extinguishers are multipurpose and will fight classes A, B, and C.

The first commercial fire extinguisher was developed in 1928 by DuGas and used a sodium bicarbonate cartridge that was pressurized with CO2. It dispensed the agent by turning a wheel valve at the top to puncture the cartridge, then pressing a lever at the end of the hose. These were the ancestors of modern hand-held dry chemical extinguishers.

A modern variation on this is a carbon dioxide extinguisher that uses compressed carbon dioxide to smother the fire by dispersing the gas over the surface of the burning material. These are lightweight and easy to use, but require the operator to have a clear view of the fire and to be careful not to discharge the fire extinguisher at the wrong angle or location, which can cause a spraying effect and make it difficult to aim.

Most home improvement stores sell multipurpose fire extinguishers that fight Class A, Class B, and Class C fires. The key is to look for a fire extinguisher with a UL (Underwriters Laboratories) rating, which indicates the unit has been independently tested and approved by a nationally recognized laboratory. Generally, these extinguishers will have a red label with white letters.

A fire extinguisher rated for Class A fires will put out ordinary combustible materials such as wood, cloth, paper, and many plastics. It also will prevent a fire from spreading by cooling the burning material.

Class B fires involve flammable liquids like gasoline, oil, and solvents. They are usually easier to fight than Class A fires because the liquids can be wiped off the surface of the fire.

Class C fires involve energized electrical equipment or wiring, and they are often harder to extinguish than other types of fires. Class C fires also involve electricity, and using water or a standard household fire extinguisher could actually conduct the fire or cause it to spread.

Class K fires are caused by vegetable or animal oils and fats that burn at very high temperatures in cooking appliances. These may also be called grease fires. They can also be considered a class B fire, but they are more likely to be conducted near energized electrical equipment and need an agent that won’t conduct electricity. AFFF fire extinguishers are blue/red in color and can be applied in either aspirated (mixed and expanded with air through the branch pipe nozzle) or nonaspirated form. They smother the fire by creating a frothy seal over the fuel and preventing oxygen from reaching it, and they don’t allow for flashback.