24th January, 2023
Not every fire is the same. Different types of fire have different hazards and risks. Using the wrong type of fire extinguisher could do more harm than good. There are six classes of fire, and each should be attacked differently to put them out safely.
Fires can be devastating. Burning, injuring, and even killing people. Damaging buildings and equipment. Interrupting business activities. Fire can end lives, and put you out of business.
Nearly 60% of businesses never recover after a fire. Make sure yours isn’t one of them.
Fire prevention is the best way to make sure that fire doesn't impact you or your business. But as well as preventing fires from starting in the first place, you should have a plan in place for dealing with fires if they do happen.
Because 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, depending on the type of "fuel" that is on fire.
Each type of fire can be put out differently, depending on the hazards involved.
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.
If any type of solid material is burning, like you would expect in a "normal" fire, then it's a Class A fire.
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, minimising risks.
The best types of fire extinguishers for class A fires are water and foam extinguishers. Water 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.
Power and wet chemical fire extinguishers also have limited suitability for Class A fires.
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.
This type of fire is more common in industrial settings, where large quantities of flammable liquids are present. Class B 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. You should consider the safe storage and use of these substances, and 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. CO2 extinguishers can also have limited suitability.
Class C fires are fires involving gases. This could be natural gas, LPG or other types of gases forming a flammable or explosive atmosphere.
Working 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 put out this type of fire is to shut off the gas supply. The best type of extinguisher to put out the fire once the supply of gas is cut off, is a dry powder extinguisher.
Metals are not often thought of as a combustible materials, but 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 temperatures, which can cause building collapse when metal joists and columns are present in a fire as structural elements.
And don't reach for the common water extinguisher on a Class D fire, water can actually act as an accelerant on metal fires.
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.
This is not strictly a class (Class E) of fire, because electricity is more of a source of ignition than a fuel. However, fires in live electrical equipment are an additional hazard.
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 the surrounding material that has been set alight by the electric current.
Making sure electrical equipment and installations are installed, inspected, and maintained correctly, will help to reduce the risk of this type of fire.
You don't want to be using water to put this fire out, or any other conductor as that could give you a fatal shock.
While you shouldn't use water to attack an electrical fire, you can use other types of fire extinguishers. The best fire extinguisher to use on electrical fires is the carbon dioxide (CO2) extinguisher. Some dry powder extinguishers are suitable for low-voltage situations.
Always turn off the power supply if you can.
Deep fat frying and spillages of flammable oils near heat sources in kitchens can result in a Class F fire. This type of fire is most common in commercial kitchens with deep-fat fryers but can also happen in homes.
Never leave food or frying equipment unattended during use.
These fires are hard to extinguish due to the heat from the oil, and using the wrong type of extinguisher can spread the burning oils and fats (and spread the fire).
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.
Find out more about the types of fire extinguishers and when to use them, or carry out a fire risk assessment for your business.
This article was written by Emma at HASpod. Emma has over 10 years experience in health and safety and BSc (Hons) Construction Management. She is NEBOSH qualified and Tech IOSH.
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