Home & Garden

The ABCs of fire extinguishers

Find the right one: Not all fire extinguishers are made the same. Photo: Graeme Maclean / Flickr

One of the most important safety items in a home, along with smoke and carbon monoxide alarms, a fire extinguisher is a necessity. The more places around your home that you can position one, the better. Make sure everyone old enough in your family is familiar with how to operate a fire extinguisher, too. Here’s most everything you’ve ever wanted to know about fire extinguishers.


Fire extinguisher ratings appear as a series of letters and numbers (for example, 2A10BC). The letters indicate the class of fire the extinguishing agent is designed for. Depending on which letter they precede, the numbers indicate either the approximate relative extinguishing potential or the size of fire that can be put out by a trained operator using that extinguisher.

The most reliable rating is that assigned by Underwriters Laboratories (UL), which appears on the equipment nameplate. (The UL is an independent entity that tests consumer products according to governmental safety standards.). Size alone is not a good measure of extinguisher effectiveness, although generally speaking, the larger the extinguisher, the longer the spray time. The efficiency of nonrated “general purpose” extinguishers is difficult to judge.


Different types of fires require different extinguishing agents. Manufacturers choose the right extinguishing agent (such as carbon dioxide, dry chemical, or foam) for each fire classification.

Your job as a consumer is to know what type of fire you want protection against and to choose an extinguisher designed to be effective against that type of fire. You do this via fire classifications — the letters (A, B, and/or C) that appear in the rating.

Class A fires are the most common, involving ordinary combustibles such as wood, paper, cloth, rubber, and plastics.

Class B fires involve flammable liquids (such as gasoline, kerosene, or oil), gasses, and greases.

Class C fires involve electrical appliances, equipment, or wiring, where the electric nonconductivity of the extinguishing agent is important (that is, when there is a risk of getting electrocuted). Note: When the equipment or wiring is de-energized (unplugged, not live), remaining combustion is Class A or B, and extinguishers designed for those fires may be safely used.


The number preceding Class A indicates the approximate relative extinguishing potential. This number relates to the square feet of ordinary combustible material the extinguisher can put out and is dependent on the type of extinguisher as well as efficiency of design and use.

The number used for Class B indicates the square footage of a deep-layer flammable liquid fire that a trained operator can put out.


Your choice of extinguisher should be based on potential use. For instance, oil, grease, and electrical fires are likely in the kitchen, garage, and car, so the obvious choice would be a BC extinguisher. However, much can be said for being prepared for any situation, so unless the application is specific, choose the most versatile extinguisher, with the largest capacity, that can be easily handled by potential users. For home use, it may be best to go with heavy-duty rated, multipurpose (ABC) dry chemical fire extinguisher.

The National Fire Protection Association recommends that you have at least one extinguisher for every 600 square feet of living area. Fire extinguishers should be located on every level of the home — the kitchen, garage, and basement should each have its own fire extinguisher. Do not mount too close to the location where the fire might occur — the user should not risk reaching into a fire or going into a burning area to get a fire extinguisher.


Staying at least 6 feet away from the fire, use these steps for effective fire extinguisher use:

P = Pull the pin.

A = Aim at the base of the fire.

S = Squeeze the handle.

S = Sweep at base of fire from side to side.

Keep your cool (though, sometimes easier said than done).

Note: Fight only minor fires. In case of a serious blaze, leave the premises immediately and notify the fire department from your mobile phone or an alarm box.


Choose and install fire extinguishers with a gauge, and check the gauge once a month. If the gauge reading is low, promptly take it to a professional for recharging (filled/pressurized). Also be sure to get it recharged after each use (do an Internet search for “fire extinguisher recharge” to locate vendors).

This article was derived in part from information from the National Retail Hardware Association.

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Julia Strzesieski is the marketing coordinator at Cole Hardware and can be reached at [email protected].