Types of fire:

If a fire does start, it can spread quickly. Knowing how to attack a fire before it grows, isn’t always straightforward. Not every fire is the same. Different fires can have different hazards and risks. Using the wrong type of fire extinguisher could do more harm than good. There are 6 different classes of fire, and each should be attacked in a different way.

Class A (Solids)

Class A fires are fires involving solids. This type of fuel could be paper and cardboard, common in offices and manufacturing. It could be furniture, or fixtures and fittings. It could even be the structure of the building. This is one of the most common types of fire because solids are the most common type of fuel and one that is hard to eliminate.

Good housekeeping should help to keep materials like packaging and waste reduced, minimizing risks. The only type of fire extinguisher you should use on a class A fire is the water extinguisher. This is the most popular type of extinguisher because it can handle most fires involving solids. But, as a conductor, it should never be used near electrical equipment.

 

Class B (Liquids)

Class B fires are fires involving liquids. Many of the fluids, liquids and chemicals used in workplaces can be flammable or explosive. Like cleaning fluids, solvents, fuels, inks, adhesives and paints. According to statistics, in 2010/11 flammable liquids accounted for only 2% of fires, but a massive 21% of fatalities. These fires are rare but more deadly than other types of fire.

So how can you protect yourself? Make sure you know what flammable liquids are used in your workplace, and carry out a COSHH assessment. COSHH assessments are a legal requirement, for any hazardous substances. This about safe storage and use of these substances, keep them in labelled containers and away from sources of ignition. Should a class B fire ignite, foam or powder extinguishers are the best types of extinguishers to attack this type of fire.

 

Class C (Gases)

Class C fires are fires involving gases. This could be natural gas, LPG or other types of gases forming a flammable or explosive atmosphere. Work with gas is dangerous, and increases fire risk. Keep stored gases in sealed containers in a safe storage area, and ensure that gas work is carried out by competent persons.

While extinguishers can be used on class C gas fires, the only safe method to attack this type of fire is to shut off the gas supply. The best type of extinguisher to put out the fire only the supply of gas is cut off, is a dry powder extinguisher.

 

Class D (Metals)

Metals are not often thought of as a combustible material, some types of metal can be, like sodium. Metals are also good conductors, helping a fire spread. All metals will soften and melt at high temperature, which can be a big problem when metal joists and columns are present in a fire as structural elements.

Water can actually act as an accelerator on metal fires, so how would you tackle a class D fire? There are dry powder extinguishers developed to tackle metal fires. The powder inside the extinguisher may vary depending on the type of metal risk it is designed for. Small metal fires can sometimes be smothered with dry earth or sand.

 

Electrical Fires

This is not strictly a class (class E) of fire, because electricity is more or a source of ignition than a fuel. However, fires in live electrical equipment are an additional hazard. You don’t want to be using water, or any other conductor as that could be fatal. Electrical fires are not given their own full class, as they can fall into any of the classifications. After all it is not the electricity burning but surrounding material that has been set alight by the electric current. Making sure electrical equipment and installations are installed correctly, and inspected and maintained, will help to reduce the risk of this type of fire.

While you shouldn’t use water to attack an electrical fire, you can use other types of fire extinguishers. Like carbon dioxide, and dry powder in low voltage situations. Always turn off the power supply if you can.

Class F (Cooking Fats & Oils)

 

Deep fat frying and spillages of flammable oils near to heat sources in kitchens can result in a class F fire. Never leave food or frying equipment unattended during use. The only type of fire extinguisher approved for use on cooking oils and fats is the wet chemical extinguisher.

For small class F fires, you could also use a fire blanket. You can find out more about the types of fire extinguishers and when to use them, or carry out a fire risk assessment for your business.