Fire Extinguisher Types, Classes & Their Uses

You may not know this but there isn’t a single fire extinguisher that works against all fires. In fact, there are five different types of fire extinguishers – water fire extinguishers, foam fire extinguishers, dry powder fire extinguishers, CO2 fire extinguishers and wet chemical fire extinguishers, each with their own subtypes. Below, we’ll look at all of those in a little more detail, so that you know what extinguisher to get for the best fire protection at your property. 

Choosing the right extinguisher based on the fire classification

The first step to finding out what is the most suitable fire extinguisher type for your building, you have to figure out what type of fire you are most likely to encounter. The fire classes in the UK are defined by the type of material that’s fueling the fire and there is five of them:

• Class A – combustible organic materials, such as wood, coal, paper and textiles
• Class B – flammable liquids, such as diesel, paint and petrol 
• Class C – flammable gases, such as methane, butane and propane
• Class D – flammable metals, such as aluminium or magnesium
• Electrical fires  – instead of a class name, these are marked with an electrical spark symbol
• Class F – cooking oils and fats (mainly relevant to kitchen fires)

The 5 types of fire extinguishers & their uses

Now that you know what fire classes there are, it’s time to see what the main five types of fire extinguishers are:

• Water and water mist fire extinguishers
• Foam fire extinguishers
• Dry powder fire extinguishers
• Carbon dioxide (CO2) fire extinguishers 
• Wet chemical fire extinguishers

Some of those can battle more than one type of fire, while the others are specially designed to work on a specific fire class. To make it easy to understand, here’s a visual representation of the different fire extinguisher types and what fire class they are best suited for. Feel free to download or share this! 

Now, let’s look at each of the fire extinguisher types in a little bit more detail! 

Water Fire Extinguishers

Water fire extinguishers are some of the most widely spread extinguishers in the UK, as they battle the most common fires – Class A fires. You’ll recognise water fire extinguishers by the red label. 

They are often found in office buildings, schools, shops, hospitals and apartment buildings. Usually, a water or water mist fire extinguisher will be placed on each floor near an exit or in any other location which has been identified as being at risk of a Class A fire during an official fire risk assessment. 

Water extinguishers attack the heat element of the fire triangle. They work by cooling down the flames, causing the burning to gradually slow down and eventually stop. 

Water fire extinguishers should not be used in case of a kitchen fire, electrical fire or a fire caused by flammable liquids or gases. 

Water spray fire extinguishers are a variation of water extinguishers which use a spray nozzle to create higher pressure and penetrate deeper into the fire. 

Water mist fire extinguishers are different. They are extremely powerful and can be used on A, B, C and F fires, as well as on electric fires (up to 1000v equipment). The only fire they cannot be used on is class D – flammable metals. 

Foam Fire Extinguishers

Foam fire extinguishers are designed to tackle Class B fires but since they use water to create the foam, they are also useful against Class A fires, which makes them very popular. Their label colour is cream. 

These fire extinguishers have a dual effect – they not only cool down the fuel but they also block the fire from the fuel source using a foaming agent called Aqueous Film Forming Foam. 

Much like water extinguishers, foam fire extinguishers are widely used across buildings in the medical, retail and educational sectors, as well as offices and rental properties. If you have flammable liquids, such as petrol, gasoline, diesel or paints in the building, then this is probably the best option for you.

If electronic equipment or a kitchen catches fire, using a foam fire extinguisher is not recommended. 

Dry Powder Extinguishers

Commonly referred to as ABC extinguishers, standard dry powder extinguishers can be used against A, B and C fires. They are also effective for fires involving small electronic equipment (up to 1000v). Specialist dry powder extinguishers also exist and those can be used against fires class D fires too. 

The dry powder extinguishers break the fire triangle by taking the heat out of the question, thus separating the fuel from the oxygen. You’ll recognise them by the blue label. 

ABC extinguishers are extremely versatile, due to their ability to extinguish fires involving organic materials to flammable gasses, liquids and even metals. However, they have one major disadvantage. Dry powder extinguishers should not be used in enclosed spaces as they are hard to clean and the powder remains in the air, which means that it can be inhaled even after the fire is extinguished. Instead, they are often used in garages, large boiler rooms and welding businesses. 

This type of fire extinguisher also cannot be used to extinguish kitchen fires and in cases where electronic equipment over 1000v is the source of the fire. 

Carbon Dioxide (CO2 Extinguishers)

CO2 extinguishers are the perfect solution to an electrical fire, although they could also be effective against Class B fires caused by flammable liquids. The label is black. 

Usually, they are used in places where a lot of electrical equipment is used, such as offices, server rooms and stores that sell electronics. They suffocate the fire until it runs out of oxygen and stops completely. 

You should not use a carbon dioxide extinguisher if the fire is caused by flammable metals, cooking oil or organic materials, such as fabrics, paper and wood. 

Wet Chemical Extinguishers

The wet chemical fire extinguisher is the only type of fire extinguisher that can be used on Class F fires – kitchen fires, involving cooking oils and fats. In exceptional situations, it can also be used against class A fires but it’s not a recommended solution. The label is yellow. 

When you use a wet chemical fire extinguisher, a mist of potassium is spread over the fire. As the potassium reacts with the fire fuel, it forms a film layer over the flames and cools down the temperature at the same time. 

As you can imagine, this type of fire extinguisher is mostly used in restaurants, commercial kitchens and canteens. It should not be used on electrical fires involving flammable metals, liquids or gasses.  

Now that you know all the main fire extinguishers types in the UK and their uses, you can decide what type you need for your property and buy a fire extinguisher that works best for your specific needs.  

Want to know more about fire extinguishers? Find out how to protect your fire extinguishers from vandalism and whether you need a car fire extinguisher.