Fire Class Guide: Understanding UK Fire Classifications from A to F
Understanding UK fire classes is vital for choosing the correct fire extinguisher, staying compliant with fire safety law, and protecting lives and property. Each class is based on the type of material burning from paper and plastics to oils, gases, and electricals, and requires a specific type of extinguisher.
This guide explains all six fire classes (A to F + electrical), their typical causes, best extinguishers, and where you’re most likely to encounter them, whether you’re managing an office, commercial kitchen, warehouse, care home or HMO.
The Six Fire Classes
- Class A fires: Combustible materials (wood, paper and textiles)
- Class B fires: Flammable liquids (petrol, paints)
- Class C fires: Flammable gases (propane, butane)
- Class D fires: Combustible metals (magnesium, lithium)
- Electrical: Electrical equipment (servers, appliances)
- Class F fires: Cooking oils (deep fryers)
Extinguisher Usage and the Six Fire Classes
The Legal Duty to Provide Fire Extinguishers in the Workplace
Under the Regulatory Reform (Fire Safety) Order 2005, every UK business must provide appropriate firefighting equipment and ensure it’s ready for use at all times. This responsibility falls to the Responsible Person (usually the employer, landlord, or manager).
What the Law Says:
Article 13 of the Fire Safety Order requires you to:
- Provide the right type of fire extinguishers for the risks in your building (e.g. Class F for deep fat fryers, not water).
- Ensure that extinguishers are easy to access, clearly signed, and simple to use.
- Make decisions based on your fire risk assessment, which must consider:
- Building size and use
- Materials and hazards present
- Number of people on site
In short, you must equip your premises with extinguishers suited to the likely types of fire and place them where staff can reach them quickly.
Class A Fires – Ordinary Combustible Materials
What is a class A fire? These fires are the most common type and can occur in virtually any environment. They are characterised by their ability to be extinguished with water or other extinguishing agents that can cool the burning material.
Type of fire: Class A fires involve ordinary combustible materials such as wood, paper, cloth, rubber, and certain plastics.
Suitable extinguishers: Water, Water Mist, (Foam, Dry Powder and Wet Chemical can also be used).
Recognising Class A Fire Risks
Fire Type
Where They Start
Bins, storage rooms, office desks, shelving, soft furnishings, display areas
Environments at Risk
Class B Fires – Flammable Liquids
What is a class B fire? These fires are fast-spreading, very dangerous, and difficult to extinguish as they can quickly reignite.
Type of fire: Class B fires involve flammable or combustible liquids, such as petrol, kerosene, oil, tar, paint, wax, and solvents.
Suitable extinguishers: Foam, Dry Powder, and Carbon Dioxide CO2.
Recognising Class B Fire Risks
Fire Type
Where They Start
Workbenches, garages, vehicle service bays, spray booths, chemical stores
Environments at Risk
Garages, workshops, manufacturing floors, warehouses, fuel storage areas
Book a Fire Risk Assessment
Class C Fires – Flammable Gases
What is a class C fire: These fires can lead to explosions if not handled correctly and require the gas source to be turned off before extinguishing.
Type of fire: Class C fires involve flammable gases such as propane, butane, methane, and natural gas.
Suitable extinguisher: Dry Powder.
Recognising Class C Fire Risks
Fire Type
Where They Start
Gas storage areas, cylinder bays, kitchens using bottled gas, maintenance yards, welding stations
Environments at Risk
Class D Fires – Flammable Metals
What is a class D fire? These fires are extremely hot and require a special extinguishing agent that does not react with the burning metal.
Type of fire: Class D fires involve combustible metals, such as magnesium, titanium, aluminum, and potassium.
Suitable extinguishers: Special Dry Powder extinguishers designed specifically for combustible metals.
Recognising Class D Fire Risks
Fire Type
Where They Start
Environments at Risk
Electrical Fires – Electrical Equipment
What is an electrical fire? These fires can be caused by short-circuits, overloaded electrical outlets, or other electrical malfunctions.
Type of fire: While not officially classified in the UK and many other countries, Class E is often used informally to describe fires involving electrical equipment.
Suitable extinguishers: Carbon Dioxide CO2 and Dry Powder extinguishers.
Recognising Electrical Fire Risks
Fire Type
Fires involving electrical equipment such as servers, wiring, fuse boxes, consumer units, kitchen appliances, or power tools
Where They Start
Environments at Risk
Offices, IT server rooms, kitchens, workshops, classrooms, retail spaces. Anywhere electrical equipment is in regular use
Class F Fires – Cooking Oils and Fats
What is a class F fire? These fires are unique to cooking environments and require a specific extinguishing agent to cool the fire and prevent re-ignition.
Type of fire: Class F fires involve cooking oils and fats, such as vegetable oils, animal fats, and greases.
Suitable extinguisher: Wet Chemical extinguishers are designed to tackle cooking oil and fat fires.
Recognising Class F Fire Risks
Fire Type
Where They Start
Environments at Risk
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Fire Class FAQs
- Class A: Solid materials (wood, paper, textiles)
- Class B: Flammable liquids (petrol, paint)
- Class C: Flammable gases (butane, propane)
- Class D: Combustible metals (magnesium, lithium)
- Electrical: Fires involving live electrical equipment
- Class F: Cooking oils and fats
- Class B fires involve flammable liquids like petrol and paints.
- Class F fires involve very hot oils or fats used in cooking.
Book a Fire Risk Assessment
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