Simple guide to buying a fire extinguisher

The options facing anyone buying a fire extinguisher might seem bewildering, especially as lives may depend on making the right choice. This no-nonsense fire extinguisher buying guide describes the key fire extinguisher types and uses, and will help to make the decision simple.

Fighting any kind of fire correctly starts long before the fire itself – with making the right decision when it comes to buying a fire extinguisher. This is because there are a variety of fire extinguisher types and uses as can be seen by this link to our fire extinguisher product page. All will put out fires, but they can’t all be relied upon for every type of fire.

Therefore, the kind you’re going to need depends on the kind of fire you, or your employees, are going to have to put out with it, which in turn will be about what’s burning. Sounds complicated? Perhaps it is, a little – but we’ve summarised the main points in this handy fire extinguisher buying guide, and indicated where you can get more information if it should be needed.

Types of fire

• Class A: Solids like wood, paper, plastic and textiles
• Class B: Flammable liquids such as petrol and oil – but not cooking oil and fat
• Class C: Flammable gases like propane and butane
• Class D: Metals, such as titanium, magnesium or aluminium
• Class E: Fires involving electrical equipment
• Class F: Cooking oil and fat

How fire extinguishers work

For a fire to start there must be fuel, oxygen, and a source of ignition, such as a spark, naked flame or other heat source. Fire extinguishers all work in the same way, by removing one of those elements from the equation in one way or another. For example, water on paper removes the fuel, because wet paper won’t burn. A wet chemical extinguisher coats the surface of the fuel (cooking oil and fat), starving it of its oxygen supply, and cooling the fire. The contents of a Carbon Dioxide fire extinguisher will remove the oxygen from around a fire, but will also disperse, allowing oxygen to return, which means the fire could restart.


Fire extinguisher guide

Usually, but not always, fire extinguishers are red. The exceptions are some small ones for domestic and leisure use, and some in clean environments like hospitals and high-end offices where a shiny polished aluminium finish is preferred. The important thing to note is a coloured panel on the extinguisher’s label. This content-specific colour tells you what’s inside the extinguisher. This ‘red body, coloured panel’ arrangement is necessary to make extinguishers conform to BS EN3.

• Red: Water fire extinguisher. Use on wood, paper and textiles, or other solid materials. NEVER use this type of extinguisher on flammable liquids or live electrical equipment. 
• Cream: Foam fire extinguisher. These can be used for fires in classes A and B. They’re not the best choice if electricity is involved, but are less dangerous than a water-filled extinguisher if they should happen to be used on live electrical equipment by accident. 
• Blue: Dry powder fire extinguisher. These have the broadest range of applications and can be used on classes A, B and C as well as fires involving live electrical equipment. Their major downside is the mess that they leave behind, particularly when you think of expensive computer kit. 
• Black: Carbon Dioxide fire extinguisher. The best choice where live electrical equipment is involved, but also effective against Class B liquid fires – but be warned. These extinguishers will put out a fire, but offer no protection against a fire starting again. 
• Yellow: Wet chemical fire extinguisher. These are ideal for kitchen and catering settings. They are designed for use on any fire involving any burning cooking oil and fat. 
• White with red lettering: Water mist extinguisher: These form a ‘curtain of mist’ to cool fires of class A and F and starve them of oxygen. As they use demineralised water to create the mist, these are environmentally-friendly. 

Further fire extinguisher resources

Rules about fire and safety in the workplace are laid down in law, and so they should be. Lives and livelihoods depend on it. We’ve produced a handy guide to fire and safety in the workplace that offers an overview of what the law requires, and places to find further information. We have also recently introduced our dedicated advice portal which contains loads of resources to help keep you on the right side of the law.