How Do Fire Extinguishers Work? You Should Know this

We all know that fire is very dangerous and that people use fire extinguishers to put out most accidental fires. For example, we had a small BBQ fire when we went camping a few years ago, and luckily we had a fire extinguisher to help us put out the fire. However, I was amazed at how quickly it put the fire out, and it made me wonder how fire extinguishers work?


You get four types of fire extinguishers and four types of fires. Each extinguisher is used for a specific kind of fire. Fires need three elements to survive; fuel, oxygen, and heat (ignition source). A fire extinguisher works by removing one of these elements to eliminate the fire.

I decided to do a basic fire fighting course to learn more about the different kinds of fire, fire extinguishers, and how to stop accidental fires from spreading until help arrives. In addition, I wanted to share the information I learned from the experts during the course to help others understand how fire extinguishers work.

How Do Fire Extinguishers Work?

No matter what kind of fire you are dealing with, all fires need three elements to grow:

  • Oxygen: Fire needs oxygen to breathe, just like we do.
  • Fuel: The substance that burns; the more fuel you have in the room, the bigger the fire will get. Fuel includes any combustible material. (the stuff that catches fire)
  • Heat: The source of ignition that causes the fuel (combustible material) to heat up to its ignition temperature. 

Fire extinguishers are made to target and eliminate one of these three elements and thus extinguish the fire. There are four different kinds of fires and four kinds of extinguishers to target and stop the fire. 

How Do You Use A Fire Extinguisher?

When faced with a small fire, you need to act fast and try not to panic. It would help if you had a basic understanding of how to use a fire extinguisher. You can use most types of fire extinguishers with this method:

Step 1

The first step is to call for help. Next, go to where the fire extinguishers are kept. Before removing a  fire extinguisher from the wall, ensure that you reach for the correct extinguisher. The information on what type of fire the fire extinguisher is made to put out is on the front of the fire extinguisher, on a printed label. 

Once you have the proper extinguisher, remove it from the bracket. Wear proper protection and check with the fire department in advance so that you know the required procedures. Read the instructions on your fire extinguishers. Make sure that it hasn’t expired. Be aware that things can explode so it is not always a great idea to use an extinguisher. There are a lot of training courses that can help you with this.

Step 2

Place the fire extinguisher flat on the ground and pull the safety pin out, removing the seal. 

Step 3

Point the nozzle as close to the base of the fire as you can get without getting in harms’ way. When using a Dry Chemical Powder extinguisher, you can aim using the hose attached to the nozzle. A Carbon Dioxide extinguisher needs to be aimed with your hands away from the bottom and nozzle, as the gas is cold enough to give you frost burns. 

Step 4

While you aim at the fire, squeeze the handles together to release the extinguishing agent.

Step 5

Using a side-to-side motion, cover the entire area and the area around the fire with the extinguishing agent. Continue until the fire is out, leave the room, go outside and wait for help to arrive.

The Best Fire Extinguishers To Use For The 4 Types Of Fires

To understand how fire extinguishers put out fires, we need to take a look at the different kinds of fires:

Water-Based Fire Extinguishers

Water-based fire extinguishers are commonly used to put out small Class A fires. Class A fires involve standard combustible materials like paper, wood, plastic, and rubber. All combustibles that burn to ash can be put out using a water-based fire extinguisher.

It’s crucial not to use water-based fire extinguishers for Class B, C, or electrical fires as the water is heavier than the liquid, and the fire will splash and get bigger. 

Eventually, as the water settles, the flammable liquid will float on top of the water and still burn. In electrical fires, you can get electrocuted if you use a water-based fire extinguisher.

Dry Chemical Powder Or Foam Fire Extinguishers

Dry Chemical Powder (DCP) of Foam fire extinguishers are used to put out Class B fires. Class B fires involve flammable liquids like benzene, diesel, petrol, oil, alcohol sanitizers, etc. These are the typical kitchen and laboratory fires.

All flammable liquid fires can be put out using DCP or Foam Fire extinguishers because the foam settles on top of the fire, depriving it of oxygen and smothering it. 

DCP is a powder that also settles on top of the fire, creates a chemical reaction that deprives the fire of oxygen, and smothers it. DCP spreads very quickly and is a standard fire extinguisher because of this in many businesses. DCP can also be used to extinguish most of the different classes of fire.

DCP is also used to extinguish Class C fires. Class C fires involve flammable gas. The best way to deal with Class C fires is to turn off the gas at the source, then use the DCP fire extinguisher to extinguish the fire that is still burning. If you can’t reach the gas source, it’s best to leave the building and wait for help. 

Carbon Dioxide 

Carbon Dioxide fire extinguishers are commonly used to put out electrical fires. Electrical fires involve any fire that starts when a faulty electrical system or wire causes a short and causes a fire. It can happen to any cables, electronics, machines, or anything that uses electricity to work. 

Before using the Carbon Dioxide fire extinguisher, you need to turn off the power at the main power switch. Then use the Cabon Dioxide fire extinguisher. The Carbon Dioxide displaces the oxygen and replaces it with carbon dioxide, smothering the fire. 


Fire extinguishers are great to put out small fires, but please be safe and call for help before attempting to put out a potentially dangerous fire. Remember to stay calm and use the correct fire extinguisher. If you have basic fire fighting experience, you know how to stay safe and put the fire out correctly. 

We have discussed the type of fire extinguishers here.