What Size Fire Extinguisher Do I Need?

Selecting the right kind of fire extinguisher can quite literally be a matter of life or death. You don’t want to be stuck in the middle of a fire only to realize that the fire extinguisher’s weight is too heavy for you to carry or the range of the extinguishing agent isn’t enough to douse all the flames. 

When you’re buying life-saving equipment like fire extinguishers, make sure you know their different types and sizes to be better equipped to protect yourself and your loved ones from emergencies.

Fire Extinguisher Sizes & Weights

The size of a fire extinguisher is an indicator of the amount of extinguishing agent that it carries. Size also depends on the type of fire extinguisher. As you might guess, the bigger the size of a fire extinguisher, the larger the fire it can contain.

Usually, the size is measured by the weight of the fire extinguisher in pounds. Weights of fire extinguishers vary from portable 2 pounds to wheel-carried 350 pounds. 

It’s important to consider the ability to move a fire extinguisher quickly. You might find yourself in a dangerous situation even if you have the right type and size of fire extinguisher but cannot carry it to the source of the fire. 

You might notice some numbers along the side of a fire extinguisher’s body that look like 2-A:10B: C – 4 lb. or 10-A:80B: C – 20 lb. They might look like a jumble of random characters at first glance, but here’s how to read them:

Class A Size Ratings – Water Equivalency 

Class A size ratings range from 1 to 40. This tells us the water equivalency of the extinguishing agent inside the canister. 1A rating is the equivalent of 1 and 1/4th gallons of water, while 2A rating means that the extinguishing agent capacity is 2 and ½ gallons of water; and so on. 

Fire Extinguisher Sizes

Class B Size Ratings – Range in Square Footage

Class B ratings tell us the area in square feet that the fire extinguisher can cover, ranging from 1 to 160. 20B would indicate that a fire extinguisher can douse a fire that has spread up to 20 square feet, while a 100B rated extinguisher would be capable of putting out a fire up to 100 square feet, and so on.

No Numeric Ratings

There are no separate size ratings for Class C, D, or K fire extinguishers because they’re usually low-intensity fires from sources like electrical appliances or kitchen stoves. Therefore, the same Class A and B size ratings apply to Class C, D, or K fire extinguishers.

Reading the Weight and Size Together

The size and corresponding weight of a fire extinguisher are usually written together and have the following variations:

  • 2-A:10B: C – 4 pounds
  • 3-A:40B: C – 5 pounds
  • 4-A:60B: C – 10 pounds
  • 10-A:80B: C – 20 pounds

Remember that these numbers indicate the capacity of the tank only. The actual amount of the agent present inside might be lower depending on how much charge the extinguisher has. Read our article on inspecting your fire extinguisher to know how much is left in a fire extinguisher.

What Size Fire Extinguisher for My House?

Small interior or exterior house fires are usually low intensity and can be put out by a dry powder extinguisher. However, the size of your house and the type of fire are major factors to consider when deciding the fire extinguisher’s size for your home. 

According to the National Fire Protection Association (NFPA), the recommendations for the fire extinguisher size and weight for a house are:

  • The living room should have a 5-10 pounds or 2A: 10: B: C fire extinguisher
  • The garage should have a 5-10 pounds or 3A: 40B-C or fire extinguisher
  • The kitchen should have a 2.5 pounds extinguisher

You should have a fire extinguisher located every 40 feet in your house.

Here are some highly-rated home fire extinguishers to choose from:

First Alert HOME1 ABC Home Fire Extinguisher Rated – Red

Amerex B402, 5 lb ABC Dry Chemical Fire Extinguisher – Red with Wall Bracket

Kidde FA110 ABC Fire Extinguishers 2 Pack – Red

As an Amazon Associate, SelectSafety earns commissions from qualifying purchases made through links in this post.

What Size Fire Extinguisher for My Apartment?

According to the NFPA standards, the selection of a fire extinguisher and how to mount it for an apartment depends on 

  • The size of the apartment
  • The fire hazard level or probability of a fire 
  • Whether the building has automatic sprinklers, standpipe, hose or other protections

Usually, a 5-pound fire extinguisher is easy to grab, store and use for apartment fires.

What Size Fire Extinguisher for My Business?

To determine the size of a fire extinguisher required for your business, you need to take into account:

  • The unique hazards within the area of operation
  • The size of the office or work space
  • The kinds of materials present in the location
  • The employee capability

A rule of thumb for determining the size of a fire extinguisher is that the larger the area of a possible fire, the larger the size of the fire extinguisher needed. It matters whether the business is operated from a room, a building, an industrial area, an outdoor setting – small areas will require smaller sizes of fire extinguishers and vice versa. 

  • Small business offices should be equipped with 5 lb or 10 lb ABC fire extinguishers
  • Large open floor plan offices should have multiple 10 lb or 20 lb ABC fire extinguishers
  • Open industrial areas used for machining, storage, packing and shipping should have multiple 20 lb ABC fire extinguishers
  • Laboratory areas require specialized fire extinguishers, depending on the types and volume of chemicals

The nature of the fire hazards impacts how quickly the fire spreads and, therefore, the fire extinguisher’s size. Depending on the industry, the workplace may have different natures of fire hazards. Flammable objects in workplaces typically involve paper, plastic, cloth and electrical equipment. 

It’s important to note that the person who’s operating the fire extinguisher matters as well. Heavier fire extinguishers might work for your business, but they might lead to a dangerous situation if they’re too bulky for your average employee to carry and use. You should have a higher quantity of extinguishers, rather than just one or two very large ones.

What Size Fire Extinguisher for a Warehouse?

Most of the warehouse fires are caused by electrical shorts or lighting equipment. Typically, warehouses require 10 lb or 20 lb 4A: 60B: C or 10A:80B: C fire extinguishers. There are many factors to consider if you want to decide the exact size and weight, and these include:

  • The rate the fire is likely to spread (fast for paper products and chemicals, slower for electrical equipment)
  • The firefighting ability of the employees
  • The size of the warehouse and adjoining offices

A larger-sized warehouse would require a higher weight of fire extinguisher. Alternatively, the weight and size might need to be lower if the employees are not well equipped to handle larger weights. Fire extinguishers need to be portable to be effective. 10 or 20 pound fire extinguishers can be handled by most people.

Most warehouses require multiple fire extinguishers (see our how many fire extinguishers article). It’s better to balance size with numbers — if employees can find and use a fire extinguisher quickly they can fight the fire and reduce its size before it gets out of control. You don’t want just one or two huge extinguishers nobody can get to or use, because they’ll be completely ineffective in an emergency.

Also, don’t forget that installing multiple fire extinguisher signs are essential for finding a fire extinguisher when you need it! Again, an extinguisher is useless if your employees can’t find it, and warehouses are notorious for having limited visibility when things are stacked up and smoke starts billowing.

What Size Fire Extinguisher for a Factory?

There are several different kinds of fire in a factory and start because of woodworking, metal processes, chemical plants, food particles and even items like carbon dust, flour, and soap. 

A portable fire extinguisher with a minimum size of 2A:20B: C or 4 pounds is required in a factory.  However, it’s much better to have 10 pound 4A: 60B: C or 20 pound 10A:80B: C fire extinguishers for factories. Fires can quickly spread and become intense in factory environments and having extra capacity available is important to put fires out before they get out of control.

In a factory, fire extinguishers need to be located at a distance of 75 feet or less (ideally every 50 feet) from each other. You want your workers to be able to easily find one in any direction and quickly get to it so it can be turned on the fire.

What Size Fire Extinguisher for My Restaurant?

Restaurants require 5 pound fire extinguishers with a rating of 3A:40B: C. The small size works best for kitchen settings because the fire is usually limited to a small source and a 5-pound extinguisher is easier to grab and use.

In large open eating areas you should install 10 pound fire extinguishers there, as well.

What Size Fire Extinguisher for My Automotive Shop?

The size of the fire extinguisher required for an automotive shop depends upon the source of the fire. Usually, auto shop fires are started by either of these sources:

  • Electrical equipment
  • Car parts

For a space the size of a home garage a 10-pound fire extinguisher is ideal, which should be rated 4A:60B: C.

A large, multi-bay automotive shop should have 10 lb fire extinguishers mounted every 2-3 working bays. If a fire starts in or around a vehicle, you want your mechanics to be able to easily reach one to put out the fire quickly and save the vehicles and rest of your shop!

For individual vehicles, the extinguisher should be 2 pounds.

What Size Fire Extinguisher for My Barn?

A barn has many organic, combustible materials like hay, cobwebs, dust, heating equipment, and rope. Depending upon the size of the barn and its layout, your fire extinguishers should be 5 lbs or 10 lbs.

Large barns should have multiple 5 or 10 lb fire extinguishers located on posts and walls, with high visibility signs to identify them.

You may also want to have a large 100-300 pound wheeled water fire extinguisher in your barn to put out any manure or hay fires that spring up.

Ideally, you should also have individual 2 lb fire extinguishers mounted on any tractors, trucks or motorized farm equipment you park in the barn because many fires in a barn are petroleum-related.

What Size Fire Extinguisher for an Office?

Determining the fire extinguisher’s size for your office requires you to understand the level of fire hazard. A few fire-hazard determining parameters are:

  • Low, ordinary, and high hazard fires.
  • Floor area per unit.
  • Travel distance in between the extinguishers.

Most office fires fall into the light-fire hazard category; because offices usually don’t have many combustible materials the way industrial workplaces or kitchens do.

Offices need a 4-pound fire extinguisher rated 2A:10B: C that covers 3000 square feet or a 10-pound commercial fire extinguisher if the office size is larger.

An office should have water and foam fire extinguishers stored 25-50 feet apart to fight off Classe A and B fires. 

To Conclude

It’s essential to consider the weight and size of the fire extinguisher whenever you’re buying one for your home, office, apartment, restaurant, warehouse, and more. There are many factors to consider in all the scenarios, and we hope this article helped narrow your choices down.

NEXT UP: How Many Fire Extinguishers Do You Need?

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Nick Klamecki, Author
About Nick Klamecki, Author

Nick Klamecki is a certified Fire and Workplace Safety expert with 15 years experience in product research and testing. He has a degree from U.C. Davis, is an active outdoorsman and spent years ensuring the safety of special needs children. Nick researches and tests workplace, industrial and safety products and provides advice on their safe use. Learn more about Nick here or connect with him on LinkedIn | Medium