Fire extinguishers are useless--until the moment when they are vital. To make sure they are ready when you are, periodically check your home's fire extinguisher(s) and perform any maintenance needed. Here's how.

How Does It Work?

Most household fire extinguishers have a gauge to indicate whether the unit is full and what to do if it isn't (refill, discard).

A fire extinguisher is an apparatus, usually containing chemicals, for putting out a fire. It extinguishes a fire by excluding oxygen so that combustion can no longer continue. The extinguisher must deliver a powerful spray of water, foam, or powder to smother the whole fire as quickly as possible, so its contents are pressurized. Some extinguishers produce a jet of carbon dioxide, a heavy gas that prevents burning.

What Can Go Wrong?

Fire extinguishers are relatively simple in function and operation, so little can go wrong with them. The primary problem with them is that they eventually leak pressure so they cannot deliver the extinguishing ingredient to the fire when needed. Make sure you check the charge meter every few months and replace the unit if it falls below the full range.

Fix-It Tip

Make sure you read and understand the instructions on your fire extinguisher before you need it.

Know the classes of fire extinguishers and what you need.

Class A extinguishers are designed to fight blazes in wood, paper, rubber, and most plastics. Install one near fireplaces and in the living areas and bedrooms.

Class B extinguishers contain dry chemicals that smother fires fueled by oil, solvents, grease, gasoline, kerosene, and other flammable liquids. Install them in kitchens, workshops, and garages.

Class C extinguishers also contain dry chemicals to smother fires in electrical equipment. Use in workshop areas and near the electrical service panel.

Most household fire extinguishers are multipurpose class A-B-C. They are effective against all of the common fires in homes and so are most popular.