What are the different types of fire?

Although all fires may look similar, the combustible materials of which they are composed are not. As a result, fires can be classed in six different ways according to the particular combustible materials which cause them. Further, as each class of fire bears a different set of chemical properties, different types of fire extinguishers are required to douse them. So, in order for you to be prepared in the event of a fire, this month, Cheshire Fire will lay out the six different classes of fire and the ways in which they should be extinguished.

Class A

Perhaps the most common class of fire, Class A fires consist of ordinary combustible materials such as wood, paper, fabric, some plastics and most varieties of refuse. Their ignition temperatures are relatively low and, once the fuel or oxygen has been depleted, will burn out.

Although many suppression techniques are suited to tackle Class A fires, water extinguishers (red band) are particularly effective and can be obtained at a low cost. However, foam extinguishers (cream band) will also serve to fight the fire.

Class B

Class B fires are those with ignition materials consisting of flammable liquids such as petrol, alcohol and some types of paint. Class B fires have a flashpoint of below 100°C, simply meaning that they burn easily, but can burn at any temperature if exposed to an external fire source such as a naked flame. On top of this, these fires spread quickly and produce thick black smoke, making them difficult to fight.

When tackling Class B fires it’s best to use a foam extinguisher to smother the flames.

Class C

Fires caused by flammable gases such as butane and propane make up those in Class C, and are arguably the most dangerous given their propensity to explode. This is why such gases are sealed in fortified metal containers.

To make things more difficult, most types of fire extinguishers are ineffective against Class C fires and have the potential to make things worse. In order to deal with such fires safely, then, ensure the gas supply has been isolated and use only powder extinguishers (blue band).

Class D

If a fire involves combustible metals such as potassium and magnesium, it belongs in Class D. Although some metals have rather high ignition temperatures, when ignited, they will transfer heat quickly and produce devastating effects.

Class D fires will burn out quickly, though, as the large amounts of ash produced will eventually suffocate the flames. That said, specifically dry powder extinguishers will fight the fire effectively.

Electrical (formerly Class E)

As you’d expect, fires in this class are caused by live electrical apparatus such as faulty wires or switchboards. They are now not classified, however, because electricity is a source of ignition rather than fuel, but electrical fires still carry their own risks with them.

When fighting an electrical fire, it is vital the source of electricity is isolated first and a water extinguisher is not used. Instead, use a CO2 extinguisher (black band) or a dry powder extinguisher.

Class F

Class F fires are caused exclusively by cooking oils and fats, both of which are common in home and commercial kitchens. They burn at extremely high temperatures and are particularly tricky to extinguish.

In light of this, wet chemical extinguishers (yellow band) have been created specifically to fight Class F fires, containing a formula which cools the fire and prevents reignition.

Do you want to bolster the fire-fighting capabilities of your business premises? Cheshire Fire provides businesses of all kinds with high quality fire risk assessments, fire safety training and fire fighting equipment. With our guidance, you can rest assured your premises will meet all fire safety legislation and remain as hazard-free as possible. To improve your workplace’s fire safety in Chester, Warrington or the surrounding areas, get in touch with our team today.