How to Choose and Use a Home Fire Extinguisher

As a minimum, every home needs a fire extinguisher kept in the kitchen. Fire extinguishers should ideally be placed on every floor of a home and in every potentially dangerous area, such as the kitchen, the garage, the furnace room, and the workshop.

Fire extinguishers should be selected based on their size, kind, and rating. The "size" of a fire extinguisher is defined by the mass of the fire-fighting chemical it contains; this mass is about equal to half the fire extinguisher's total mass. Standard household fires can be put out using extinguishers weighing between five and 10 pounds, but those weighing two and a half to five pounds are usually sufficient.

Each extinguisher has a specific "class" rating indicating the range of fires it can put out. Standard combustibles, including wood, paper, and cloth, are safe to use with a Class A extinguisher. Carbonated water is often what they use for their charge, and while it is cheap and effective, it can be harmful when used against grease fires (because the pressured water can spread the burning grease) and electrical fires (because the water stream and wetted surfaces can become electrified, delivering a possibly fatal shock). Class B extinguishers are designed to put out fires caused by flammable liquids such as oil, grease, gasoline, and other chemicals. Powdered sodium bicarbonate is typically used as their charge (baking soda).

For flames involving electricity, use a Class C extinguisher. Most use dry ammonium phosphate. Since halon has a harmful effect on the ozone layer, Class C extinguishers that contain halon gas are no longer produced for home use. Because the gas surrounds the fire, stifling it, and then disappears without leaving chemical residue that can damage the equipment, halon extinguishers are approved for use around pricey electronic devices like computers and televisions. Also, unlike conventional extinguishers, halon may expand to reach and extinguish fires in otherwise inaccessible areas, such as around obstacles.

For domestic usage, extinguishers classified as B:C and even ARC are more common than those classified only for use on specific types of fires. While ARC extinguishers are the best option for most home fires, BC extinguishers are preferable in the kitchen due to their superior performance on grease fires (their sodium bicarbonate charge combines with fats and cooking oil to generate a wet foam that smothers the fire).

A fire extinguisher's "rating" indicates how well it puts out a certain kind of fire. A higher rating indicates that the extinguisher is more effective against the specified type of fire. Class A extinguishers have ratings that correspond to the approximate gallons of water needed to match their capacities (for example, a 1A rating indicates that the extinguisher functions as well as about a gallon of water), and Class B extinguishers have ratings that correspond to the approximate square footage of fire that can be extinguished by an average, nonprofessional user. There are no ratings for extinguishers in Class C.

You should invest in a large extinguisher, such as one with a 3A:40B:C rating, to cover an entire level of your home. These cost about $50 and weigh close to ten pounds. Invest in a 5B:C unit for your kitchen; they weigh around three pounds and cost about $15. It's more cost-effective to purchase two smaller extinguishers than one larger one to provide more fire safety in the kitchen. Most fires in kitchens start small and can be put out with a small extinguisher; smaller extinguishers are easier to handle than larger ones, especially in tight spaces; and having multiple small extinguishers is more cost-effective than having one large one because even a partially used extinguisher must be recharged before it can be used again.

Because grease and oil fires are so common in garages, a 5B:C extinguisher is another smart investment there. Get some IA:LOB:C extinguishers for the garage and the utility room. Also, these typically weigh in at around three pounds (though some can go up to five) and cost in the neighborhood of $15. Always make sure to purchase an extinguisher that has been approved by Underwriters Laboratories.

Place fire extinguishers in easily accessible locations, such as near exits. Use special brackets designed for this purpose; these fasten to wall studs via long screws and may be withdrawn in an instant. The plastic brackets that come with many fire extinguishers aren't as sturdy as the marine brackets that have been authorized by the U.S. Coast Guard. Extinguishers should be installed at a height of four to five feet above the floor, though they can be placed as high as six feet if necessary to prevent access by youngsters. Don't tuck fire extinguishers away in a dark corner where they won't be seen in the event of an emergency.

Invest in fire extinguishers that feature pressure gauges so that you can see at a glance if they are still fully charged. Check the pressure gauge once a month, and have the extinguisher refilled at the store you bought it from or through your local fire department if the gauge indicates it has lost pressure or after it has been used, even for a few seconds. Inoperable or expired fire extinguishers must be replaced before they pose a safety risk. Regardless of the manufacturer's recommendations, a fire extinguisher shouldn't be kept for more than ten years.

Smaller extinguishers are notoriously difficult to recharge, and the process sometimes ends up costing as much as buying a new one. Recharging a fire extinguisher is an unnecessary expense, so it's recommended that you just get a new one instead. To do so, empty the extinguisher's contents (which are harmless) into a paper or plastic bag and then throw away both items. Reusing and recycling extinguisher cylinders is possible.

Every member of the household, with the exception of extremely small children, should get familiar with the proper use of a fire extinguisher. To do this, it is helpful to lay down a large sheet of plastic and use the area underneath it as a test bed (the contents of most extinguishers will kill grass and stain pavement). Proper use of a fire extinguisher necessitates positioning yourself six to 10 feet away from the fire, with your back to the nearest escape.

(If smoke or heat make it impossible for you to reach within six feet of a fire, it's best to just leave the building and call the fire department instead of trying to put it out yourself.) With the extinguisher held vertically, the locking pin can be withdrawn from the handle and the nozzle directed at the fire's base. Squeeze the handle to release the fire retardant, and then sweep the nozzle from side to side to douse the fire. Keep an eye out for the fire to start up again and be ready to spray.

Fire extinguishers for chimneys

Two or three oxygen-starving sticks, which may be purchased from stores that specialize in fireplaces and wood stoves, should always be on hand for anyone who uses either of these heating methods. Flue or stovepipe fires can be rapidly put out by tossing the sticks into the blaze. If the fire alarm is sounding, it is best to leave the house and contact the fire service right away.