What Are the Different Types of Fire Extinguishers?
There are five main types of fire extinguishers:
Water.
Powder.
Foam.
Carbon Dioxide (CO2).
Wet chemical.
Each type is easily identifiable by their names, colours, and sometimes their hoses. Depending on their size, some may not come with a flexible hose, such as smaller foam or aqua water spray extinguishers.
Let’s take a look at each type of fire extinguisher, their uses, and their risks below.
1. Water Extinguishers
There are two types water extinguishers: water spray and dry water mist.
Standard water extinguishers
These will be solid red and will have the word ‘water’ or ‘aqua spray’ printed across them in white text. They are your classic model: they dispense water at a high pressure to extinguish flames.
Water extinguishers are only suitable for class A fires, which means they can fight fires that involve wood, cardboard, paper, plastics, fabric and textiles, and other solid materials.
Warning: do not use water extinguishers on burning fat and oil fires and electrical appliances.
Water extinguishers can sometimes contain chemical additives that improve their effectiveness by up to 300%. The chemicals remove the water’s natural surface tension so that it soaks into burning materials more effectively when used.
2. Powder Extinguishers
There are three types of powder extinguisher: ABC powder, M28 powder, and L2 powder.
ABC powder extinguisher
These types of extinguishers will say ‘powder’ in white text over a blue rectangle, and underneath the rectangle will be written ‘ABC powder’.
Foam extinguishers are identifiable by the word ‘foam’ printed within a cream rectangle on their bodies. They are primarily water based but contain a foaming agent, which has rapid flame knock-down and a blanketing effect. It smothers the flames and seals vapours so that re-ignition cannot occur.
As their name suggests, these are designed to combat class A, B, and C fires – those involving solids, liquids, and gases. The powder acts as a thermal blast that cools the flames so burning cannot continue. Due to their non-conductive nature, they are also suitable for fighting electrical fires. However, they do not effectively penetrate the spaces in equipment easily, so the fire could still re-ignite.
Warning: do not use on domestic chip or fat pan fires (class F).
The downside to ABC powder extinguishers is that they pose a danger of inhalation when used in close spaces. They also leave residue behind that is difficult to clean up and causes damage to soft furnishings, carpets, and electrical equipment. This is why it’s advised you use a different type of extinguisher for workplaces with electronics, such as an office with computers.
3. Foam Extinguishers
They are suitable for fighting class A and B fires.
When used against class A fires, the user can simply point and spray. However, when used against class B fires – those with flammable liquids – they should not be sprayed directly into the liquid. This could cause the fire to be pushed and spread to surrounding areas. The best method of application is to spray the foam nearby so that it can build up and flow across it.
4. Carbon Dioxide (CO2) Extinguishers
These types of extinguishers can be identified by the text ‘carbon dioxide’ or ‘CO2‘ printed in white on a black rectangle. They also have a distinct type of hose.
Carbon dioxide extinguishers are used for combating class B and electrical fires – they suffocate the fire by displacing oxygen in the air. Because they do not leave any substances behind and so minimise damage done to equipment, unlike other extinguishers, they are particularly useful for offices and workshops where electrical fires may occur.
5. Wet Chemical Extinguishers
These types of fire extinguishers are identifiable by the words ‘wet chemical’ printed across a yellow rectangle. It also has an extended hose that you can hold and point, which is useful when fighting fires on a kitchen top.
Wet chemical extinguishers are designed for combating fires that involve class F fires. They are effective because they are capable of stopping fires that are of an extremely high temperature, particularly cooking oils and fats. They also discharge gently, stopping the burning oils and fats from being pushed and splashing to surrounding areas or even the user.
The chemicals contained within the canister dispels the flames, cools the burning oil, and produces a soap-like solution that seals the surface and prevents re-ignition of the fire.
The best method of application is to spray in slow circular motions. The user should empty the entire contents onto the oils or fats. Otherwise, the fire may re-ignite.
Warning: wet chemical extinguishers are usually not recommended for class B fires – those involving liquids. Also, although they are capable of combating class A fires, they are not as effective as other extinguishers at doing so.