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. 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. The weight of the fire extinguisher varies from portable 2 pounds to wheel-carried 350 pounds. 

It’s important to consider the transportation of a fire extinguisher. You might find yourself in a dangerous situation even if you have the right type and weight of the 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 tell us the water equivalency of the extinguishing agent inside the canister, which usually ranges from 1 to 40.  1A rating is the equivalent of 1 and 1/4th gallons of water, while 2A rating means that the extinguishing agent is as efficient as throwing on 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 the fire extinguisher can douse a fire that has spread up to 20 square feet, while a 100B rating would indicate a potential of putting out a fire of 100 square feet; and so on.

No Numeric Ratings

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

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 lb.
  • 3-A:40B: C – 5 lb.
  • 4-A:60B: C – 10 lb.
  • 10-A:80B: C – 20 lb.

Remember that these numbers indicate the capacity of the tank. The actual amount of the agent present inside might be higher or lower depending on how much charge the extinguisher has.

Fire Extinguisher Types

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What Size Fire Extinguisher for My House?

A house fire is usually short-range and can be put out by 1kg of a dry powder extinguisher. However, the size of your house and the fire’s origin is a major factor 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 the house are:

  • The living room should have a 2A: 10: B: C or 5-10 pounds fire extinguisher  every 40 feet.
  • The garage with inflammable objects should have a 3A: 40B-C or 5-10 pounds fire extinguisher installed.
  • The kitchen should have a 2.5 pounds extinguisher.

If that extinguisher doesn’t seem to be enough to douse the flames, then you need to immediately evacuate the premises before you get injured. 

What Size Fire Extinguisher for My Apartment?

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

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

Usually, a 5-pound fire extinguisher is easy to grab, store and use in small-range 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 room.
  • The kinds of materials present in the room.
  • 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. 

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. Usually, the flammable objects in workplaces 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. 

What Size Fire Extinguisher for My Warehouse?

Most of the warehouse fires are caused by electrical disturbances or lighting equipment. Typically, a large-sized warehouse needs 4A: 60B: C or 10A:80B: C fire extinguishers sizes. There are many factors to consider if you want to decide the exact size and weight, and these include:

  • The rate at which the fire is spreading.
  • The capacity of the people present.
  • The size of the room.

A larger-sized room 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.

What Size Fire Extinguisher for My Factory?

There are several different kinds of fire in a factory and start because of woodwork, metal processes, chemical plants, food particles, and even items like carbon dust, flour, and soap.  A portable fire extinguisher with a minimum rating of 2A:20B: C or 4 pounds is obligated in an industrial setting.  There needs to be one of those at a distance of 75 feet or less in between one another.

What Size Fire Extinguisher for My Restaurant?

A fire extinguisher’s ideal weight for a restaurant would be 5 pounds fire extinguisher 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.

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, the fire is started by either of the sources:

  • Electrical equipment
  • Car parts

For a space the size of a home garage where non-vehicle sources start the fire, a 10-pound fire extinguisher is ideal, which will be labeled 4A:60B: C. If the fire is limited to the vehicle, the extinguisher required doesn’t need to be larger than 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 fire, a fire extinguisher required in a barn might range from:

  • 2.5 pounds
  • 5 pounds
  • 10 pounds 

Ideally, they should be mounted on tractors and trucks in the barn because most of the fires in a barn are petroleum-related.

What Size Fire Extinguisher for My 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 industries or kitchens do. At most, you will have a water and foam fire extinguisher stored 75 feet apart from one another in an office; these kinds of fire extinguishers fight off Classes A and B of fires. 

A light- or low-hazard fire needs a 4-pound fire extinguisher rated 2A:10B: C that covers 3000 square feet or a 10-pound commercial fire extinguisher if the office’s size is larger.

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.

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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

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