​Do You Know How to Choose the Right Size Fire Extinguisher?

In the movies, the hero or heroine swings fire extinguishers easily, putting out the fire and saving the day. So naturally, many assume that all fire extinguishers are about the same size and yield the same amount of power. That's untrue. Fire extinguishers range from portable 2 lbs. to massive 350-pound canisters. They also accommodate different-size areas by square foot.

Are you sure you have a suitable fire extinguisher for your home, office, school, or community building? And are enough of them placed the correct distance apart, so you're ready in an emergency?

In This Article

Because there can be quite a bit of confusion about what size fire extinguisher one needs, today's article discusses the different size ratings of extinguishers, what size room they can accommodate, and which you should choose for your needs.

The ratings and suggestions below come from the National Fire Protection Association's (NFPA) 2022 standards. Wondering what the experts say about the size you need? Contact us today for information and a free quote.

Why the Weight of Your Extinguisher Matters

Fire extinguishers vary in size, but generally, the larger the extinguisher, the larger a fire can contain before running empty. To choose the suitable fire extinguisher for your needs, you will need to find the rating, which includes the water equivalency by weight. You also need to know that the weight listed differs from the extinguisher's size.

Here's how to find out which extinguisher you need:

1. Read the Weight Class on the Canister

You will find fire extinguisher weight ratings on the side of the canister.

Look at the canister you're considering buying. You should see a code consisting of letters and numbers. It will look like 10-A:80B: C – 20 lb., or another combination of similar letters and numbers.

While the temptation may be there to just go by what the weight size is (for example, that would be 20 lbs.), there's a little more to it. We'll describe below how to read the size and class of fire extinguishers properly so you choose the type you need.

2. Class C, D, and K Fire Extinguishers

These three classes are standard residential and commercial fire extinguishers. Because of this, they do not have their weight class.

Instead, class C, D, and K fire extinguishers fall under Class A and B, as described in the two sections below:

3. Class A and B Water Equivalency Ratings

Class A and B ratings give the water equivalency by volume. In other words, the extinguishing agent will yield as much power as a certain amount of water.

Class A: You usually see a number between 1 and 40 on the canister. Each number equals approximately 1.25 gallons of water.

For example, a 1 rating = 1.25 gallons of waterpower; a 2 rating = 2.25 gallons of waterpower.

Class B: Class B extinguishers are a bit different. They tell the size in square feet, from 1 to 60, that the extinguisher's agent will cover.

In this case, the number equals the square footage. So a 1 rating = 1 sq. ft.; a 160 rating = 160 sq. ft.

4. Make Sure You Choose the Right Class

Putting out a fire isn't just about the size of the room. You need the right fire extinguisher agent (chemicals) to prevent the type of fire that may happen in that area.

Check out this article to discover the types of fires that can happen and which class of fire extinguisher you will need.

Fire Extinguisher Sizes in the Home

Except for the kitchen and the garage, most experts recommend 5-10 lb. fire extinguisher every 40 feet.

For the garage, make sure you take into account what types of fire may occur. Check out this article [link Fire Extinguisher Safety Tips article] for fire extinguisher classes and electrical, grease, and other types of fires. Most of the time, a five lb. fire extinguisher will do.

Unless it is very large or commercially used, the kitchen only needs a fire extinguisher larger than 2.5 lbs. Make sure you're using the suitable kitchen fire extinguisher class. Check out the link above for tips.

Fire Extinguisher Sizes in the Office

The size depends on the following:

• How large the room is
• What flammable materials are in the room
• Any unique hazards (cloth, chemicals, etc.)

Workplaces often have paper and may have cloth or other flammable materials. Some offices have small equipment prone to an electrical fire. So, in addition to the square footage of the room/area, make sure you're choosing the suitable class.

Fire Extinguisher Sizes in a Factory or Commercial Garage

There are minimum fire extinguisher size requirements in industrial areas. Make sure you comply. Refer to OSHA's current needs for your industrial setting for the required size, number, and placement.

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Fire Safety Equipment is your #1 supplier of high-quality fire equipment and accessories. We are committed to providing high-quality products and unparalleled service to construction professionals throughout North America. Request a quote today to help you choose the best fire extinguisher for your building!