Fire extinguishers

The different types of fire extinguisher and their uses

Fires are a frequent occurrence in the UK, and can have a devastating impact on a business. For this reason, it is essential that employers install adequate fire control measures and promote good fire safety practices among their staff in order to prevent them from taking place.

One key measure that can be used to provide fire protection in the workplace is to install suitable fire extinguishers and train staff in their use. In this article, we will look at the different classes of fire, and the different types of fire extinguisher and extinguishing agent that can be used to tackle them.

Fire extinguishing

How many classes of fire are there?

Before looking at the different types of fire extinguisher, it is important to understand the classes of fire and what they mean.

There are six different classification of fire:

  • Class A fires
  • Class B fires
  • Class C fires
  • Class D fires
  • Electrical fires
  • Class F fires

What is a Class A fire?

Class A fires involve solid combustible materials, such as wood, paper, plastic and fabric. This type of fire is very common, and can spread quickly if there are enough combustible materials to sustain it.

What is a Class B fire?

Class B fires involve flammable liquids, such as petrol, diesel, ethanol, paint, turpentine and paraffin. These liquids and their vapours can be ignited easily, and should be kept away from open flames as a result.

What is a Class C fire?

Class C fires involve flammable gases, such as propane, butane, methane and hydrogen. Flammable gases can be ignited very easily, and pose a serious fire and explosion risk in workplaces that make use of them, highlighting the importance of ensuring that they are stored correctly and away from open flames.

What is a Class D fire?

Class D fires involve combustible metals, such as magnesium, aluminium, lithium, titanium and potassium.

This type of fire is not common because of the very high temperatures metal requires to ignite. However, this high temperature also makes metal fires very dangerous if they do occur.

What is an electrical fire?

Electrical fires are caused by faults in electrical appliances, such as faulty wiring, frayed cables, short circuits and overloaded adapters. They are sometimes informally referred to as 'Class E' fires.

Electrical fires are not considered as their own class of fire because the electrical equipment ignites the surrounding materials and is not the thing that burns.

What is a Class F fire?

Class F fires involve cooking oil or fats that have been ignited. These fires occur most commonly in restaurants, and are often related to deep fat frying.

Much like combustible metals, cooking oil and fats require very high temperatures to ignite, making class F fires very dangerous.

What are the different types of fire extinguisher?

There are five different types of extinguisher that are suitable for different types of fire:

  • Water extinguishers
  • Foam extinguishers
  • Powder extinguishers
  • Carbon dioxide extinguishers
  • Wet chemical extinguishers

It is important that the correct type of extinguisher is used to tackle a fire, otherwise they may end up making the situation worse. Thankfully, all fire extinguishers feature symbols to indicate the fires on which they are suitable for use, making it easy to avoid this mistake.

Water extinguishers

There are two main types of water fire extinguisher: standard water extinguishers and water mist extinguishers. Standard water extinguishers have a red band on top, and are suitable for class A fires only.

In contrast, water mist extinguishers feature a white band and can be used on class A and F fires, as well as electrical fires if they use non-conductive water.

Foam extinguishers

Foam fire extinguishers are primarily water-based, and contain a foaming agent that smothers the fire. They have a cream band on top, and can be used to tackle class A and B fires.

Powder extinguishers

Powder fire extinguishers (dry powder extinguishers) have a dark blue band on top, and will contain one of three different powders: ABC, M28 and L2.

  • ABC powder has a cooling effect and is suitable for use on class A, B and C fires, such as those involving burning materials,  liquids and gases.
  • M28 and L2 powders are designed specifically for class D fires, with the main difference between them being that M28 powder cannot be used on lithium-based fires.

Powder fire extinguishers are highly effective, and can be used on a range of fires. However, the powder can be dangerous to inhale and it can cause damage to certain items when used, such as carpets and electrical equipment, which may make these extinguishers unsuitable for certain environments.

Carbon dioxide (CO2) extinguishers

Carbon dioxide (CO2) fire extinguishers feature a black band on top and have a large, distinctive conical hose. They work by displacing the oxygen in the air and suffocating the fire, and are suitable for use on class B and electrical fires.

Carbon dioxide fire extinguishers are great for workplaces where there is a high risk of an electrical fire taking place because they are not substance-based and cause little damage when used.

Wet chemical extinguishers

Wet chemical fire extinguishers have a yellow band on top, and usually feature a long hose. They work by cooling the oil or fat that is burning and creating a seal over its surface area to prevent it from re-igniting.

Wet chemical extinguishers are designed specifically to tackle class F fires, but can be used on class A fires too.

At Commodious we offer two fire safety training courses, one for all staff and another that is designed specifically for fire marshals. Use the links below to find out more information about these courses: