What do the different colours on fire extinguishers mean?

1 November 2022 AGF Fire Protection

fire extinguishers and their uses

Fire extinguishers are colour-coded according to the contents of the extinguisher, so you know which type of fire they are designed to be used on. In this blog we’ll take a closer look at the meaning of each colour. The more you know about it now, the more likely it is that, if you ever need to use one, you’ll be able to quickly pick and use the correct extinguisher.   

Red – water extinguisher

Water extinguishers have a red label. Water fire extinguishers are used for Class A fires which are fuelled by flammable solids such as paper, cardboard, plastics, fabric and wood. 

There are two main types of water extinguisher – standard and dry mist:

  1. The standard water fire extinguisher will produce a high pressure spray. 
  2. The dry mist water extinguisher converts the water into microscopic particles that are then ‘dry’ enough to be used safely on most types of fire. The particles help to extinguish flames by suffocating them at the same time as cooling them. 

Cream – foam extinguishers 

Foam fire extinguishers have a cream label. Foam extinguishers are used for Class B fires which are caused by flammable liquids such as petrol, paint and white spirits. Foam extinguishers are water-based which means they can also be used on Class A fires (flammable solids). The foam works by blanketing the flames and depriving them of oxygen at the same time as sealing in the vapours to ensure reignition does not occur. When using a foam extinguisher on flammable liquids, do not direct the spray at the liquid, instead direct the spray at the foam at the edge and build up the foam until it flows across the fire. 

Blue – dry powder extinguishers 

Dry powder fire extinguishers have a blue label. They are also known as ABC extinguishers because they can be used on Class A (flammable solids), Class B (flammable liquids) and Class C fires. Class C fires are caused by flammable gases such as hydrogen, methane, liquid petroleum gas (LPG) and acetylene. The powder works by cooling the fire in order to extinguish the flames. It is not a good idea to use dry powder extinguishers in confined spaces as this could lead to a risk of inhaling the powder. The powder also leaves a residue that is hard to remove and can damage soft furnishings, carpets, and electrical equipment. 

Black – carbon dioxide (CO2) extinguishers 

Carbon dioxide (CO2) fire extinguishers have a black label. Carbon dioxide fire extinguishers can be used on electrical fires and can also be used on Class B (flammable liquid) fires. They work by displacing the oxygen in the air, which suffocates the fire. They are easily identifiable because they come with a large horn-like nozzle. When operating a CO2 extinguisher, it’s important to remember that the gas becomes extremely cold during discharge, so you risk damage to your hands if you are holding the horn, base or pipework. 

Yellow – wet chemical extinguishers 

Wet chemical fire extinguishers have a bright yellow label. They are specifically designed to be used on Class F fires. Class F fires are caused by cooking oils and fats, so you will only need wet chemical extinguishers in a kitchen environment. They can also be used on Class A fires (flammable solids). The extinguisher works by gently discharging its contents to stop the burning oils being pushed or splashed into surrounding areas. The chemicals in the extinguisher cool the oil and produce a soap-like solution that seals the surface and prevents reignition.

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