Classes of Fire – Understanding the Different Classes & Types of Fire in the UK

Fires are divided into 6 different classes in the UK – Class A, B, C, D, E and F.

In this guide from the CPFP team we explain each class of fire and identify the appropriate fire extinguisher required to effectively put each type out. Using the wrong fire extinguisher can in fact sometimes do more harm than good, so it’s important you know which type of extinguisher is designed for which type of fire.

Class A Fire

Referring to fires fuelled by solid materials like wood, plastic and furniture, Class A fires are one of the most common types of fire. This class of fire is often used for bonfires and for other controlled circumstances in order to provide heat and light. However, in less restricted environments they can grow and develop very quickly, resulting in fires which are out of control.

The type of fire extinguisher required to put out a Class A fire is the water extinguisher.

Class B Fire

Class B fires are fuelled by liquids like oil and petrol. A lot of the fluids, liquids and chemicals used in workplaces can be flammable or explosive, so these types of fire can be quite common in certain industries. These fires reach very high temperatures, giving off lots of heat and spreading quickly. They also produce toxic smoke and fumes, therefore making them particularly difficult to control.

Foam and powder extinguishers should be used to put out Class B fires.

Class C Fire

A Class C fire is the burning of flammable gases. This includes gases like butane, propane and petroleum gases that are stored in commercial premises. These gases are all extremely dangerous and even just a single spark has the potential to create an explosion, so it’s imperative that they are stored in sealed containers in safe storage areas.

These types of fires can be hard to put out as it can be difficult to isolate the source and stop its release. The gas supply should be turned off and a dry powder extinguisher should be used.

Class D Fire

Class D fires are defined as fires ignited by combustible metals, such as titanium, magnesium and potassium. Although it requires a lot of heat to ignite most metals (solid lumps of metal are harder to ignite than powdered metal), metals are good conductors, which helps the fire to spread. Also, all metals soften and melt at high temperatures, which presents a serious problem if metal joists and columns are present in a building’s structure.

Water is ineffective and can actually act as an accelerant on metal fires, so water extinguishers need to be avoided for Class D fires. Instead, a dry power extinguisher should be used.

Class E Fire

Class E fires are fuelled by electrical appliances like TVs and computers. Faulty equipment, damaged wiring, short circuits and overloaded sockets/switchboards are all common causes of fire.

Fires caused by electricity should never be extinguished using water or foam as they act as a conduit and the consequences could be fatal. Instead, a CO2 gas or a dry powder extinguisher should be utilised.

Class F Fire

Class F fires are fuelled by cooking fats, greases and oils, usually in a kitchen setting. They ignite at very high temperatures so are difficult to extinguish.

A wet chemical extinguisher should be used to tackle this type of fire. A fire blanket can also be used for small Class F fires.

Passive Fire Protection UK with CPFP

Fire prevention is the most effective way of ensuring your building and staff isn’t impacted by fire. Here at CPFP we specialise in providing passive fire protection services to residential, commercial and industrial buildings across the UK. From cavity barrier installation and maintenance to penetration sealing, we help properties of all sizes to prevent the spread of fire, thus reducing the physical effects it can have.

To find out more about our services or how we can help ensure your building is appropriately protected from fire, please don’t hesitate to get in touch today.

See more: Everything You Need to Know About Passive Fire Protection

See more: A Beginner’s Guide to Cavity Fire Barriers

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