A fire extinguisher is red metal cylinder with a trigger handle on top and a short black hose hanging down. A close look reveals a wire ring terminating in a long metal pin in a hole passing completely through the handle. Its small, round gauge is divided into two red sectors and a narrow green wedge.
Where to find them:
A fire extinguisher normally hangs waist-high on a quick-release mounting bracket near kitchen, laundry room, garage, and workroom exits. May also be found in hallways outside bedrooms or inside bedroom closets. Sold by hardware stores and home centers. or available from tool hire companies. The tank, trigger, and nozzle arrangement are characteristic; the red color is customary but some extinguishers are white or chrome.
Primary Use:
Putting out a small fire before it spreads and before the fire department arrives. An extinguisher may also help suppress flames along your exit route.
Operating Principle:
A harmless gas such as nitrogen or carbon dioxide, when compressed inside a metal cylinder and released through a nozzle, can propel foam or dry powder along with it. Most household extinguishers contain either sodium bicarbonate or ammonium phosphate, powdery chemicals that interfere with the runaway oxidation we see as a flame.
Variations:
Small extinguishers have a nozzle in the handle, while larger ones have a flexible black hose the same length as the cylinder. According to the National Association for Fire Prevention, for home use choose an extinguisher with a minimum rating of 2-A:10-B:C, which means it will be effective on type A fires (ordinary combustibles such as paper, wood, and fabric), type B fires (flammable liquids such as cooking oil and gasoline), and type C fires (involving live electricity). Home extinguishers should be rated A:B:C on their labels; it’s unwise to rely on B:C or A:B ratings. The numbers in the rating, while not exactly a measurement, do allow you to compare the effectiveness of various extinguishers, with higher being better.
Safety Note:
Fire extinguishers can lose their charge of propellant and become ineffective. The little round gauge warns you: If the needle slips out of its green wedge, you must recharge or replace the extinguisher.