Understanding different types of Fire Extinguishers
When it comes to fire safety, the first piece of equipment which comes to mind is often the fire extinguisher. It’s the first line of defence against fires, present on business premises, in public places and in schools. However, if you or the person responsible for health and safety in your organisation were presented with a fire extinguisher- would they know how to use it? And, past simply operating a fire extinguisher, would they know what sort of extinguisher it was and what types of fire it can be used against?
To make sure the persons responsible for fire safety in your organisation can identify the different types of fire extinguishers and operate them effectively, we recommend the NEBOSH Certificate in Fire Safety. It covers all the core knowledge needed to reduce the risk of and combat fire in the workplace, including how to create an effective evacuation procedure.
Providing those responsible for fire safety in your organisation with training is a legal requirement, though it is beneficial for any team member to have this knowledge, as you never know when an emergency could occur. Knowing about the different types of fire and fire extinguisher in particular is great for any employee, as it is the go to piece of equipment for fighting a fire. In this post, we’ll outline just that so you know how to identify different types of fire extinguisher, as well as which fires each type can fight.
Classifications of Fire:
To understand the different types of fire extinguisher you first need to know what the different types of fire are. There are 6 in total, which are categorised based on what substance is fuelling the fire.
Class A- fires involving primarily organic solids, including wood, paper, and plastics.
Class B- fires involving flammable liquids, such as paint or oil, as well as liquefiable solids such as fats and waxes, excluding cooking fats and oils.
Class C- Fires involving gases.
Class D- Fires caused by burnable metals, such as magnesium and aluminium
Class F- Fires involving deep fat fryers/oil fryers
Electrical fires- Fires caused by electrical equipment and appliance, such as computers and machinery.
Knowing the class of a fire is crucial for fighting it effectively, as there is no one extinguisher which can combat all 6. Instead, fire extinguishers are designed to fight specific types of fire, at most effective against 2 or 3 types. If you use the wrong extinguisher on a fire it could worsen the blaze, placing those nearby at even greater risk.
Types of Fire Extinguisher:
Fire extinguishers are designed to stop fires, as you would expect, but do you know exactly how they do this? For a fire to burn it requires oxygen in gas form, a fuel or substance to burn, and a source of ignition to begin the fire. This trio is known as the fire triangle and is a concept you may well be familiar with. Fire extinguishers function by cutting off one of these three components.
Removing Oxygen:
By cutting off the oxygen from a fire, through equipment such as a fire blanket or the use of foam, the fire is starved of oxygen and can’t sustain itself.
Removing the Fuel
Removing the fuel or flammable substance from a fire, whether through turning off the gas supply in the room or moving away flammable objects, means the fire will die as soon as it runs out of fuel.
Removing the Heat
The heat stemming from the ignition of a fire is what lets it continue burning. By removing it, typically with water, the heat is absorbed by the liquid, cooling the fuel, and preventing it from burning further.
Using these three methods, fire extinguishers are designed to tackle specific categories of fire. There are 5 main types:
Water:
Fire Extinguishers which use water dispense the liquid through a high-pressure nozzle as a jet or spray and are effective at fighting Class A fires. They must never be used on electric fires or Class F fires.
Water based extinguishers have a red body, label, or band.
Foam:
Foam extinguishers are designed to smother flames, creating a barrier which stops oxygen getting to the fire. They are effective against Class A fires and some Class B and C fires, provided the fuel is not an alcohol or liquified gas which would cause the foam to break down.
Foam based extinguishers have a cream body, label, or band.
Dry Chemical Powder:
There are two types of dry chemical powder extinguisher. The first, termed ‘ABC Powder’, should be used on, as the name suggests, Class A, B and C fires. The powder produces a cloud which smothers the fire, starving it of oxygen.
The second type is a Class D Powder Extinguisher, which again, as the name implies, should be used Class D fires. In these extinguishers the spray coats the metal, drying to form a crust which prevents oxygen reaching the fire.
ABC powder extinguishers have a blue body, label, or band.
D powder extinguishers have a violet body, label, or band.
CO2:
Carbon dioxide extinguishers also starve the fire of oxygen, though these do so by smothering the flames in gas. It can be used on electrical fires, as the gas can penetrate small gaps in the electrical equipment. It is also suitable for use against Class B fires but should not be used on Class D fires, as the gas can react with the metal and explode.
CO2 based extinguishers have a black body, label, or band.
Wet Chemical:
These extinguishers are used for Class F fires, as the liquid chemical reacts with high temperature fat and forms a foam layer on the surface of the liquid. This stops oxygen from getting in and boiling fats from bubbling over. Wet Chemical extinguishers are also suitable for use on Class A and B fires.
They can be identified by a yellow body, label, or band.
Clean Agent:
The final extinguisher type we’ll cover is termed ‘Clean Agent’, named as such because it uses inert gases or liquids which are non-conductive and non-volatile. They can be used on electrical fires as they do not leave any liquid behind when sprayed and can also be used on Class B and C fires.
Clean Agent extinguishers have a green body, label, or band.
Choosing the right Fire Extinguisher:
With so many types of fire and fire extinguisher, it is important that the right extinguisher is selected when a fire breaks out. As you now know, extinguishers can be identified based on a coloured label or band on the body. They also have labels to indicate what classes of fire they should be used on.
It’s unlikely a workplace will need every type of fire extinguisher though, as many would not be needed in certain settings. With this in mind, it is crucial for an organisation to consider the potential hazards of their workplace when purchasing fire extinguishers. For example, a restaurant which uses deep fat fryers will need a wet chemical extinguisher in case the fryers catch fire.
| Extinguisher Type | Fire | Class | Colour Band | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| A | B | C | D | F | Electrical | |||||
| Water | x | Red | ||||||||
| Foam | x | x | Cream | |||||||
| Dry Chemical Powder (ABC) | x | x | x | x | Blue | |||||
| Dry Chemical Powder (D) | x | Violet | ||||||||
| CO2 | x | x | Black | |||||||
| Wet Chemical | x | x | Yellow | |||||||
| Clean Agent | x | x | x | Green |
Another key consideration after selecting suitable fire extinguishers is providing training to employees so they can use them effectively. The standard way to use them can be remembered as ‘PASS’-
Pull the pin from the top of the extinguisher
Aim at the base of the fire with the nozzle
Squeeze the lever to spray
Sweep from side to side to across the fire to put it out
However, some extinguishers require more specific guidance to operate, such as foam extinguishers, which must be sprayed at the rear of a fire first, then spread across the fuel or substance to form a blanket.
Fire Extinguishers in the Workplace:
As with any piece of equipment in the workplace, fire extinguishers should be checked regularly. Government guidance suggests that inspections take place at least once a month to check the extinguisher:
Is clearly visible
Has not been tampered with or damaged
Has not been used
Is still suitable for use, as indicated by its pressure gauge
Extinguishers should also undergo a basic service annually, as well as extended services either every 5 or 10 years depending on their contents.
Fire extinguishers are pressurised, which is why they spray so effectively when used. Because of this it’s important that, when inspecting an extinguisher, you check that the pressure gauge is within the green area; if it is not the pressure isn’t right, so it won’t work properly when used. If you find this is the case, the extinguisher will need to be serviced. By doing so you can avoid the worst-case scenario in your workplace- a fire breaking out while you have no means of fighting it.
Fire safety is vital in any workplace, so understanding fire extinguishers and their uses is a must. This means making sure you have the correct extinguishers to fight any fires likely to occur in your workplace, having them located somewhere accessible, and knowing which extinguisher to use in an emergency.
At Phoenix we can help train your employees to use extinguishers and teach them what to do in the event of a fire through our Fire Safety Awareness Training. The designated fire marshal in your organisation can also benefit from taking Phoenix’s Fire Marshal Training, or the NEBOSH Certificate in Fire Safety, as these courses provide all the information they need to reduce the risk of fires and lead emergency procedure, should a fire occur.
If you have any questions or would like to enquire about our range of fire safety courses, contact us today.