Every home should have at least one fire extinguisher, but there are many kinds with different purposes. Home improvement blog This Old House deciphers what label codes mean, so you can buy the right kind for each room.
Photo by greenkozi.
The letters on a fire extinguisher let you know what type of fire the extinguisher works best on. The numbers just before the letters give you even more information on the canister's effectiveness.
A is ordinary combustibles like wood, paper, and cloth; B is flammable liquids, such as gasoline or cooking oil; and C is live electricity. In the fine print on the label, these letters are preceded by numbers - for example, 3-A:40-B:C - which are the extinguisher's classification rating. The numbers, assigned by Underwriters Laboratories, tell the extinguisher's relative effectiveness against each type of fire, regardless of its weight or the chemical it uses. The higher the number, the greater the effectiveness (and likely the higher the price).
In other words, a 4-A rated extinguisher will combat a wood fire better than one rated 2-A. Fire extinguishers come in different sizes: a small 1kg canister is fine for the car, but you'll probably want a big 4.5kg for your garage or workshop.
Hit up the post for more information on how to choose the right fire extinguisher, then check out This Old House's video for a refresher on how to use it:
How to Choose and Use Fire Extinguishers [This Old House]