Reviewed by Chuck Roydhouse
Updated March 7, 2023
If there’s a fire in your home, your first instinct may be to run, far and fast, while calling 9-1-1 on your cell phone. That’s a perfectly acceptable response—fires are not to be taken lightly. They have the potential to cause enormous damage and injury.
But, if you’re properly equipped, you can stop a small fire before it grows. All you need is a fire extinguisher and the knowledge of how to use it. Here’s an overview of fire extinguishers, how to use them, and how to maintain them.
A fire extinguisher is a portable device used to put out small fires.
Fire extinguishers are usually red, and cylinder-shaped with a nozzle or hose at the top. They spray pressurized fire-retardant materials.
Common handheld extinguishers use either carbon dioxide or nitrogen as the pressurizing gas. Depending on the class of extinguisher, they extinguish the fire with water, chemical powder, or even the propellant gas itself.
Fire extinguisher classes are based on the types of fires they can fight. The classes actually refer to different kinds of fires, rather than to the fire extinguisher itself.
The most common fire extinguisher type is ABC—meant to fight fires of classes A, B, and C.
“[The ABC fire extinguisher] is a combination-type fire extinguisher, and that’s typically what you find in a home,” says retired professional firefighter and CSIA President Chuck Roydhouse.
BC fire extinguishers (without the A) are also available for home use.
Aside from the fire extinguisher classes, they also come in varied sizes, denoted by the weight.
“10-pound fire extinguishers are great for home workshops or garages,” says Roydhouse. “5-pound fire extinguishers are great for kitchens and laundry rooms, and 2-pound fire extinguishers are great for keeping in your car.”
Here are the different classifications of fire:
Fires fuelled by ordinary combustibles such as paper, wood, cloth, or plastic. Water and chemical suppressants (wet or powder) can extinguish Class A fires.
Fuelled by flammable liquids or gases, such as gasoline, petroleum oil, or propane. You should never use water to put out a Class B fire, as the water will spread the fuel source and thus, the fire. Dry chemical suppressants or CO2 are effective ways to fight Class B fires.
Fires involving electronic equipment. Any other class of fire that involves electronic equipment can also be a Class C fire. These fires are best fought with dry chemical or CO2 suppressants, as water can conduct electricity from the fire through the body of the person holding the fire extinguisher, causing serious injury.
Fires involving combustible metals like lithium, potassium, or magnesium.
According to Roydhouse, Class D fires aren’t particularly common in home settings.
“You’ll usually only find these in different sheet metal shops,” says Roydhouse. “If you put regular water on the [metal] fire, it burns so hot that it pulls the oxygen out of the water and burns the water to basically pure oxygen. It will explode like a flashbulb going off in your face.”
Needless to say, Class D fires aren’t as straightforward as Classes A-through-C.
“For these situations,” says Roydhouse, “there’s a special fire extinguisher called MET-L-X, which uses what looks like graphite or pencil shavings to form a shell over the fire. If you were to have a metal fire outside, you could also cover it with dirt.”
Class D fires usually require specialist intervention, but fortunately you’re unlikely to experience one at home.
Fires involving cooking oils and fats. Generally, that means kitchen fires. These are similar to Class B fires, but their unique qualities get them a separate rating. You should never use water to extinguish a Class K fire, as water can spread out the fuel source and make it much more dangerous. Class K extinguishers (or other equipment like fire blankets) are the best way to put out a Class K fire.
A note about Class K fires:
Although your kitchen is one of the places in your house most prone to fires, you may not actually need a Class K extinguisher; they’re designed for commercial kitchens. An ABC fire extinguisher (combined with good kitchen fire safety practices) should be enough for your home kitchen.
You can also differentiate Fire extinguishers by the type of firefighting material they have inside.
Water, carbon dioxide (CO2), and dry chemical extinguishers are the main three types:
Water fire extinguishers are uncommon, since they’re less versatile than other types. These are only effective at fighting Class A fires.
CO2 fire extinguishers spray pressurized CO2 to put out fires by starving them of oxygen. They’re used to fight Class B and C fires, and are commonly used in areas with lots of electrical equipment.
Dry chemical fire extinguishers are the most common type and include the typical ABC fire extinguisher. These can be in ABC or just BC varieties, so make sure you know which type you have. The dry chemical (usually something with a fun name like monoammonium dihydrogen phosphate) separates the fire from its oxygen source and interrupts the chemical reaction taking place. These extinguishers also contain pressurized non-flammable gas like nitrogen, which propels the chemical towards the fire.
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Most home fire extinguishers are of the ABC variety and come in sizes from 5-20 pounds. The weight refers to how much firefighting material they hold; their actual weight in the hand is heavier.
Also found on household extinguishers is a label indicating the severity of the fires they can handle. The higher the number, the larger the size of the fire they can handle. This is called a UL rating.
Always look for a fire extinguisher that features the “UL” or “ULC” certification, as this denotes that it’s been tested and approved by Underwriters Laboratories, a safety certification organization.
There is one UL rating for Class A extinguishers, and another for Class B and C extinguishers. Here’s what to look for on your fire extinguisher label:
The “1-A” is the Class A rating, with the 1 being the water equivalency. 1 is equal to 1.25 gallons of water. On most home fire extinguishers, this number rangers from 1 to 5, but can be higher on a large extinguisher.
The “10-B:C” part of the label is the Class B and C rating. The number in this part tells you how many square feet of fire it can extinguish. The example above is a small fire extinguisher, which is capable of extinguishing 10 square feet of fire. This number can range from 1 to 40.
Fire extinguishers do need regular inspections and maintenance. You don’t want to wait for a fire to break out to find your extinguisher has failed.
“[Fire extinguishers] do need to be maintained on a regular basis, so you’ll want to check with the manufacturer specifications on how often they need to be used for maintenance,” says Roydhouse. “You can find this information on the tag located on each individual fire extinguisher.”
You should check all standard extinguishers monthly and have them serviced annually by a professional.
During your monthly checks, inspect the pressure gauge to make sure the needle is in the green zone; if not, fix or replace the unit.
Make sure the safety pin is still present, and the cylinder is free of damage. If it is damaged, have a professional examine the unit.
As well, you’ll generally need to have your extinguisher refilled or recharged about every five years.
“After a while when they sit, they have to be hydrostatic tested,” says Roydhouse. “Sometimes the chemical settles and needs to be dumped out and recharged.”
Make sure you keep up inspections and service so you can rely on your extinguisher at any time. Fires don’t announce themselves in advance and you need to be prepared.
Whichever type of extinguisher you purchase, be sure that everyone in the family knows where it is stored—preferably near an exit to the room—and that everyone who is old enough knows how to use it. Read the instructions carefully and review them prior to your annual family fire drill.
“If you don’t know how to use a fire extinguisher and want to learn how before you actually need it, the nice thing is that you can stop by any fire station and they’ll be glad to show you the correct way to use a fire extinguisher,” says Roydhouse.
“Also, in October, during Fire Prevention Week, fire departments have open houses or will host something in a town square, where they’ll bring fire equipment, light small fires, and show you how to use the different extinguishers. They’ll help you learn how to use them, so you’re comfortable.”
If you need to brush up on your fire extinguisher skills, we’ve prepared a quick guide on the steps you should familiarize yourself with.
If a fire starts, follow these steps:
Quickly figure out an escape route. If the fire is too large or moving too quickly, don’t stay to fight it. Otherwise, grab the extinguisher and get ready to use it.
To use a fire extinguisher most effectively, stand six to eight feet back from the fire.
To use a fire extinguisher effectively, try to remember P.A.S.S.
P.A.S.S. is a handy acronym for the steps in using an extinguisher to fight a fire. P.A.S.S. stands for Pull, Aim, Squeeze, Sweep:
While using the P.A.S.S. method remember to keep your back towards a clear exit in case the fire becomes more dangerous. Don’t use a fire extinguisher on a blaze that’s too large—don’t risk your safety.
Keep an eye on the area of the fire, even if you think you’ve extinguished it. There may be embers or sparks that can catch and flare up again.
Once you’ve extinguished the flames, call the fire department to come and inspect the site to be sure the fire is completely out and no further action is needed.
If you can’t extinguish the fire yourself, leave the scene and find a safe place. Call 9-1-1 (or your local emergency number) as soon as it’s safe to do so.
“If you’re not sure whether it’s safe for you to use the fire extinguisher or you’re not sure how to use it, alert everyone else and leave the building,” says Roydhouse. “Once outside, call 911 from an outside phone source — a neighbor across the street, someone’s cell phone.”
This video will also show you how to use a fire extinguisher.
Now that you’re up to speed, be sure to purchase an extinguisher and be prepared to use it.
Using a fire extinguisher isn’t rocket science, but there are a few common mistakes that people make with them.
“The biggest thing you need to consider is,” says Roydhouse, “are you physically able to use the fire extinguisher? They’re not hard to use, but you’ve got to be able to lift it and hold it. So make sure to buy one that you can physically handle.”
He continues, “when you use a fire extinguisher, don’t aim the fire extinguisher directly at the centre of the fire. You want to do a sweeping motion from the outside edges and work towards the centre.
“If you do shoot right in the centre, the pressure can make the fire spread more in a larger area.”
On a similar note, make sure you’re aiming at the base of the flames, not shooting through them.
Another common mistake?
Not ensuring you’ve got a clear escape route.
“If you’re going to try to extinguish the fire, make sure you have an escape route,” says Roydhouse. “You don’t ever want to let the fire get between you and your escape route. If you extinguish the fire, you’re going to have some aftereffects like smoke and toxic fumes. Are you able to get away from those fumes? That’s the biggest thing.”
A 5-pound ABC dry chemical fire extinguisher will last about 14 seconds. A 5-pound CO2 extinguisher will last about 9 seconds.
When you pull the trigger on a fire extinguisher, you don’t have long, so make sure you’re aiming at the base of the flames when you pull the trigger.
Fire extinguishers do expire, and should be inspected regularly.
“Fire extinguishers, depending on the type of material inside—whether that’s a dry powder material, a carbon dioxide material, or pressurized water— will have different life expectancies, anywhere from 5-12 years,” says Roydhouse.
All fire extinguishers should feature a manufacturing date somewhere on the unit.
According to the Canadian Centre for Occupational Health and Safety, you should remove a fire extinguisher from service when:
You should also remove a fire extinguisher from service once it’s passed its expiry date, or when a professional inspection has determined that its useful life has ended.
The fire tetrahedron refers to the four elements that must be present for a fire to burn: fuel, heat, oxygen, and a chemical reaction.
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About the expert: Chuck Roydhouse
Chuck Roydhouse is a retired professional firefighter, owner of Clean Sweep of Anne Arundel County, and President of CSIA (Chimney Safety Institute of America). He has a degree in Fire Science & Safety from Shepherd University and 25 years of experience as a career firefighter. Chuck has been serving the chimney industry for 30 years as a CSIA Master Chimney Sweep.
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