Your five-part guide to fire extinguishers - part 5

There are 5 main fire extinguisher types – Water, Foam, Dry Powder, CO2 and Wet Chemical. You should have the right types of fire extinguisher for your premises, or you may not meet current regulations.

There are six classes of fire: Class A, Class B, Class C, Class D, ‘Electrical’, and Class F.

  • Class A fires – combustible materials: caused by flammable solids, such as wood, paper, and fabric

  • Class B fires – flammable liquids: such as petrol, turpentine or paint

  • Class C fires – flammable gases: like hydrogen, butane or methane

  • Class D fires – combustible metals: chemicals such as magnesium, aluminum or potassium

  • Electrical fires – electrical equipment: once the electrical item is removed, the fire changes class

  • Class F fires – cooking oils: typically a chip-pan fire

In this part of your five-part guide, we will be looking at Wet Chemical  Extinguishers.

Wet chemical extinguishers are designed for use on Class F fires, involving cooking oils and fats.  They can also be used on Class A fires although it is more usual to have a foam or water extinguisher for this type of fire risk.

Label Colour: Yellow

Use for:

•    Cooking oil/fat fires
•    Organic materials such as:
•    Paper and cardboard
•    Fabrics and textiles
•    Wood and coal

Do not use for:

•    Flammable liquid or gas fires
•    Electrical fires
•    Flammable metals

How wet chemical extinguishers work:

Wet chemical extinguishers create a layer of foam on the surface of the burning oil or fat, preventing oxygen from fuelling the fire any further. The spray also has a cooling effect.

Types of premises/business who may need CO2 extinguishers:

•    Commercial kitchens
•    Canteens

Where to locate CO2 extinguishers:

•    Place near to the source of the fire risk