How To Size Your Fire Extinguisher

A fire extinguisher is an essential piece of equipment for any business. It can help you put out a small fire before it becomes a significant disaster. But how do you know what size fire extinguisher to buy? This blog post will discuss the different factors that you need to consider when sizing your fire extinguisher.

5 Classes Of Fires And The Extinguishers

This section explains the different classes and the kinds of fires they’re suitable for:

  • A – Common combustibles include cloth, wood, paper, rubber, cardboard, and certain types of plastics.
  • B – Lighters and other flammable items are also present, so these fires need a foam barrier to be put out.
  • C – This can include everything from electrical equipment such as an electrical panel, wiring, and motors to simply the wires themselves.
  • D – All metals, including synthetics and alloys, that are combustible.
  • K – This chemical is used in commercial kitchens to combat fires involving cooking oils and animal fats.

Fire Extinguisher Size Ratings

You can measure the capacity of a fire extinguisher in gallons. A “Class A” fire involves combustibles, such as an office or factory. The rating determines how much water it can put out. For Class A fires, the rating is measured in integers from 1 to 40. Class B fires are measured in integers from 1 to 640. The higher the values, the larger the fire that can be put out.

Class A Size Ratings – Water Equivalency 

The Class A Size ratings on the extinguishers tell us how much water the extinguishing agent in the canister is equivalent to, which usually ranges from 1 to 40. The equivalent of 1 and 1/4 gallons of water gets a 1A rating, while a 2A rating implies that the extinguishing substance involves 2 and 3/4 gallons of water; and so on.

Class B Size Ratings – Range in Square Footage

On the other hand, Class B ratings tell us how big an area the fire extinguisher may cover, ranging from 1 to 160 square feet. A 20B rating indicates that you can extinguish a fire with up to 20 square feet of surface area, while a 100B rating suggests the capability of extinguishing a fire covering 100 square feet; and so on.

Size of the Room and Fuel Load

Do you have a modest-sized room with minimal combustible materials or a central warehouse or business location where the fuel load is more significant, and a fire has more area to spread? The difference between a 5-lb extinguisher and a 30-lb extinguisher depends on the room size and fuel load.

Capabilities of Employees

A large, high-capacity fire extinguisher is useless unless your staff is physically capable of lifting and operating it. If your extinguisher is too heavy or bulky, depending on the abilities of the average employee, you could be creating a hazardous situation. Most non-disabled individuals will probably have no trouble utilizing a 5-pound fire extinguisher as a general rule. However, using anything heavier than 5 pounds may become more complex for some people.

When purchasing a fire extinguisher for your home, business, apartment, restaurant, warehouse, or other location, it’s essential to think about the size of the unit. There are numerous variables to consider in each scenario, and we hope this post assists you in making your selections.

Need some help finding the right fire extinguisher? Contact Fire-Alert today to discuss your needs!

While many people may not know everything about fire safety, they can almost certainly recognize one essential piece of equipment: the fire extinguisher. Indeed, this red fire-fighting device is often the first line of defense against small fires in many homes and businesses. However, it’s only going to be effective if you know how to use it properly.


While you can take a course in fire safety if you really want to get comfortable with a fire extinguisher, it’s not necessary. The next time you go to use a fire extinguisher, all you need to remember is PASS: Pull, Aim, Squeeze, and Sweep. Let’s learn more about the PASS method and other fire safety basics below.


What are the Different Classes of Fire Extinguishers?

Before you use an extinguisher, you need to make sure you have the right one for the type of fire. The following are the different classes of fires and extinguishers.


  • Class A: ordinary combustibles, like wood, paper, and cloth
  • Class B: flammable liquids like gas, paint, and oil
  • Class C: electrical fires
  • Class D: combustible metals and metal alloys
  • Class K: cooking fires with oils and fats


Look for one of these classifications on the label of a fire extinguisher to determine if it’s appropriate for the job.

What is the PASS Method in Fire Safety?

The PASS method is an easy way to remember how to use a fire extinguisher in an emergency. After verifying that you’re using the correct extinguisher for the type of fire, follow these steps:


1. Pull

The first thing you need to do is pull out the pin that prevents you from pressing the handle on the fire extinguisher. This is a safety feature that helps ensure the extinguisher won’t accidentally go off in someone’s hands.


Look for the pin near the top of the extinguisher. After you locate it, just pull it out to unlock the handle.


2. Aim

Standing from a safe distance, aim the nozzle low, toward the base of the fire.


3. Squeeze

Once the nozzle is pointing in the right direction, squeeze the handle. Try and squeeze it slowly and evenly for best results. Then, to stop the stream, simply release the handle.


4. Sweep

While squeezing, sweep the nozzle of the extinguisher from side-to-side. Make sure you’re always pointing toward the base of the flames as you sweep the area.


Can a Child Use a Fire Extinguisher?

Though the steps are fairly basic, the National Fire Protection Association (NFPA) doesn’t believe that children shouldn’t use portable fire extinguishers. This is due to many reasons, such as:


  • It’s against NFPA’s message to get out and stay out if they encounter a fire
  • They may not be able to judge whether the fire is small enough for an extinguisher
  • Children may not be physically capable of handling the extinguisher safely and effectively
  • They may not know what to do if the fire spreads


If an adult is around, they should always be the one to operate a fire extinguisher. Children should be taught to leave the situation as soon as possible.


Looking for fire extinguisher services for your home or business? Click here to contact Fire Alert today!

If you ask someone where to find a fire extinguisher in their home or workplace, there’s a good chance they’ll be able to point you in the right direction. However, if you try asking a follow up question about how to use the fire extinguisher, then…well…they may be less helpful.


This isn’t surprising, as many people go their whole lives without ever having to use a fire extinguisher. While it’s great that they haven’t been put in such a dangerous situation, this also means their inexperience with fire extinguishers could work against them in an emergency situation.


If this sounds like you, then you’ve found the right article. Let’s go over the basics of fire extinguishers to help keep you and everyone around you safe in a dangerous situation.


Fire Classes

A fire extinguisher isn’t a one size fits all deal – you have to use different ones for different types of fires. There are 5 common classes of fire, including:


  • Class A is for freely burning combustibles, like paper, wood, and cardboard.
  • Class B is for burning liquids or gasses, like kerosene, gasoline, oil, and grease.
  • Class C is for electrical fires, like those involving appliances, circuit breakers, and outlets.
  • Class D is for fires involving combustible metals, like potassium, sodium, titanium, and magnesium
  • Class K is for cooking-related fires, like cooking oils and fats


A lot of fire extinguishers found in homes and businesses are labelled as Class ABC, so they can be used for multiple types of fires. You can typically find the remaining two types, Classes D and K, in factories and commercial kitchens respectively.


Fire Extinguisher Types

There are various types of fire extinguishers available, but the following are the most common ones.


  • Dry chemical extinguishers are filled with powder or foam. They’re appropriate for Class A, B, and C fires. 
  • Water extinguishers contain water. They’re suitable for Class A fires.
  • Carbon dioxide extinguishers are filled with carbon dioxide. They work best on Class B and C fires.
  • Wet chemical extinguishers contain a potassium solution. They are best for Class K fires.
  • Dry powder extinguishers typically contain either a sodium chloride or a special graphite base. They are ideal for Class D fires.


How to Use a Fire Extinguisher

Portable fire extinguishers tend to be quite effective. In fact, a survey by The National Association of Fire Equipment Distributors reported that they were able to extinguish fires nearly 95% of the time. This may be because they have been designed so that anyone can use them – all you have to remember to do is PASS.


  • Pull the pin and release the locking mechanism.
  • Aim the nozzle at the base of the fire while maintaining a safe distance.
  • Squeeze the trigger slowly to release the extinguishing agent.
  • Sweep the nozzle from side-to-side until you are certain that the fire is out.


Keep in mind that portable fire extinguishers are only meant for small fires, so they only contain so much of the extinguishing agent. Therefore, you should always have an escape route ready to go in case the extinguisher runs out before the fire does.


For more on fire extinguishers, and to take advantage of our mobile extinguisher services, click here to contact Fire-Alert today!

Fire extinguishers are a handy and effective way of dealing with small fires in your home or business. All you have to do is just spray away in the direction of the flames and you’ve changed a potentially disastrous situation into a manageable one.

While that’s great, of course, all that spraying can leave quite a mess! Before you go back to business as usual, you’re going to want to clean up all that residue. And depending on the type of fire extinguisher, some cleaning methods are certainly better than others.

Check Your Fire Extinguisher

Before you start cleaning up, make sure you know what chemicals are in your fire extinguisher. Check the tag or label for information about the type and class of the agent inside. 

If you find that you have a pressurized water or CO2 extinguisher, then you don’t need to worry about cleaning up any chemical residue. Just thoroughly dry the area and it should be fine.

For foam fire extinguishers, first dilute the residue before allowing it to dry. Afterward, you may also consider sanitizing or spot cleaning if there’s any remaining residue.

Cleaning up Dry Chemical Fire Extinguisher Residue

These are the most common fire extinguishers out there because they can put out class A, B, and C fires. Dry chemical extinguishers typically contain agents such as monoammonium phosphate, potassium bicarbonate, and sodium bicarbonate, which will leave you with a corrosive powder.

  1. Remove any excess residue by sweeping or vacuuming.
  2. Combine 50% isopropyl alcohol and 50% warm water and spray the area. Let it soak for 5 minutes, then rinse with warm water.
  3. For sodium and potassium bicarbonate residue, mix 98% hot water with 2% vinegar and wash the area. Let it soak for 5 minutes, then rinse with warm water.
  4. For monoammonium phosphate residue, mix hot water and baking soda. Let it soak for 5 minutes and rinse with warm water.
  5. Clean the area again with soap and water, and then use a fan to help it dry.

Cleaning up Wet Chemical Fire Extinguisher Residue

These are typically found in commercial kitchens and restaurants, as they are used to put out grease fires.

  1. Put on goggles and gloves to protect yourself from the residue.
  2. Make sure all fuel sources in the area are turned off.
  3. Using hot water and soap, scrub the area with a cloth or sponge.
  4. Thoroughly rinse all affected surfaces, and then allow the area to dry.

Cleaning up Dry Powder Extinguisher Residue

You’ll often find these in warehouses and factories as they can be used to put out fires involving titanium, magnesium, and other combustible metals.

  1. Put on goggles and gloves to protect yourself from the residue.
  2. Remove any excess residue by vacuuming or brushing the area.
  3. Put all of the collected residue in a sealed bag and throw it away in the trash.
  4. Clean any remaining residue with a damp cloth.