Introductory Note: Do not use a fire extinguisher on a burning fire unless you feel you are able and that it’s safe for you to take on the task. If in doubt, call your local fire service.
What Types of Fires Are There?
It’s important to use the right fire extinguisher for a specific type of fire.
Before you by a fire extinguisher, it’s best to clarify in your own mind as to what type of fire you’re likely to be concerned about in your property. These are classed in 5 groups, Class A, B,C,D and F (or K in the USA):
- Class A – combustibles such as wood, paper, clothing, trash or anything else that leaves an ash
- Class B – flammable liquids and gases such as oil and petrol.
- Class C – Formerly known as class E in Europe, this is for Electrical Fires.
- Class D – Combustible metals e.g. Magnesium
- Class F – Also classed as K in the USA. This includes cooking oils and fats such as grease or animal fat
The above has been sourced from this list of Fire Classes.
What Type of Extinguishers Are There?
Following on from the above, there are five main types of extinguishers that can be used at home, in your car or caravan:
- Carbon Dioxide (CO2)
- Wet Chemical
- Dry Water Mist
- Dry Powder
Water Fire Extinguishers
When tackling a fire in the home where the fuel is paper or wood, using a water extinguisher is good as it drenches the material and eliminates the fuel at the same time. You should avoid using these types where an electrical fire has started as water doesn’t mix well with electricity and you may be prone to getting electrocuted. Most water extinguishers have an additive mixed into them which makes it quite safe to use on electrical fires, but it’s best not to take the risk in most instances where an electrical fire has broken out unless absolutely necessary.
Foam Fire Extinguishers
Can be used on flammable liquids, chip pan fires, oils and petrol. This extinguisher sprays out an expanding layer of foam, cooling down the burning material and acting as a carpet to stop oxygen fuelling the fire. Like the above, most can be used on electrical fires, but it’s best checking first.
Carbon Dioxide Fire Extinguisher
This is a good one for electrical fires as it leaves no residue i.e. the electrical items can probably be used again afterwards. The extinguisher contains pressurised CO2 gas, so when spraying the strong jet of CO2 on a fire, you are depriving the burning fuel of any oxygen. It’s important to remember that once you’ve eliminated any fire, check that there are no burning embers as once the CO2 has dissipated and O2 comes back, it could provide enough oxygen for the fire to start up again.
Due to the jet pressure, it’s best not to use this on liquids which could be forced around the room e.g. in a deep fat fryer.
Wet Chemical Fire Extinguisher
These are specifically designed for use on chip pan fires and burning oil. The specially adapted hose comes with a lance which sprays out a layer of foam o the burning material.
Dry Water Mist Extinguishers
A small jet of mist is released from the nozzle which dampens the surface of the burning material and cools it down. By creating a layer of mist, you are also depriving the burning material of oxygen.
This type of extinguisher is good for deep fat fryers, chip pan fryers and hot liquid fires as you are not blasting a jet of water or gas at the source of the fire which could make things worse.
Some of the brands, such as UltraFire contain de-ionised water, meaning the conductivity has been eliminated. This means you can also use this type of extinguisher on electrical fires.
Dry Powder Extinguishers
While these are suitable for fighting class A, B or C fires, British Standard does not allow for this type of extinguisher to be used at home, in the office or in cars/caravans. We will explain this later on.
As for the product, it has strong fire fighting capabilities and the powder doesn’t enter the fabric of the burning material you’re trying to control. In effect, the powder is coated onto the burning material, creating a kind of carpet and halting any oxygen from fuelling the fire.
It should be noted that the powder will have no effect on cooling the temperature of the fire, so if you don’t get to the source of the fire, there is a chance that it could reignite.
The reason British Standard has disallowed this type to be used at home and the office is that in small and enclosed spaces, the powder can be accidentally inhaled by the user.
General Notes on Fighting a Fire
Due to the versatility of Dry Water Mist Extinguishers, we’d usually opt for this type on a more regular basis.