Portable Fire Extinguisher – Classification

Fires are classified in four groups A, B, C, and D





  • Class A fires – are fires involving organic solids like paper, wood, etc
  • Class B fires – are fires involving flammable Liquids.
  • Class C fires – are fires involving flammable Gasses
  • Class D fires – are fires involving Metals

Fire Classifications



Electrical fires are not included, as they can fall into any of the classifications. However if you use a water extinguisher you must isolate the electric supply first as you could be electrocuted. In addition it must be  remembered that certain electrical apparatus maintain a lethal charge for some time after they have been switched off. What should you do if you discover a fire? You must get everyone out as quickly as possible and call the fire brigade. However you may discover a fire in its very early stages and think that you can deal with it yourself. The first thing that you should remember is that fire spreads very quickly. Even a small contained fire can quickly spread, producing smoke and fumes which can kill in seconds. If you are in any doubt do not tackle the fire, no matter how small. You can put yourself at risk by fighting the fire. If in doubt, get out, call the Fire Service out and stay out.

New F Class for fire extinguishers

The British Standards Institution (BSI) published a standard which introduced a new fire classification for cooking oil and fat fires, Class F, which was BS 7937 and now has been replaced by BS EN 3-7 2004 + A1 : 2007 Characteristics, performance requirements and test methods.

Colour coding of Extinguisher

Fire Class FThe type of extinguisher is identified by a colour coding as indicated below. The old fire extinguishers standard required the whole of the body of the extinguisher to be b painted the appropriate colour code. You will find these extinguishers in many premises and these are still legal , you do not need to change them unless the the extinguisher is defective and need to be replaced. New extinguisher use the new standard BS EN 3.


  • Water extinguishers are coloured signal red.
  • Other extinguishers will be predominantly signal red with the manufacturers label, a band or circle covering at least 5% of the surface area of the extinguisher of a second colour to indicate the contents of the extinguisher. I prefer the band around the extinguisher to be used because it can be seen fromany angle.
  • The old standard, the entire body of the extinguisher was colour-coded.

Fire extinguishers colour-coded green, are vapourising liquids (Halons), and have been illegal, with some exceptions like aircraft and the military, since the end of 2003 as the result of the Montreal protocol.

Consequently you may see any of the above methods of colour coding but the indicating colour always indicates the type of extinguisher medium.

Fire Extinguisher Colour Code
Not using the above colour coding means the fire extinguisher does not conform to the British standard and therefore cannot display the Kite mark. If a specific piece of legislation requires them to conform to the British Standard, then they would be illegal.


Written by

Jeff Stewart is the Founder of Stewart Fire Protection Ltd. Based in Liverpool and offering full Fire Protection Services on a Nationwide Basis. This includes the supply and maintenance of Fire equipment and Fire Safety Training. Jeff has over 25 years experience in the Fire Safety Industry.