Fires are classed in 6 different categories depending on the fuel that is burning. Class A fires are the most common type. This type of fire involves solid fuel sources such as wood, paper, and fabric.
The fire class system means you can fully understand what types of fire may occur in your workplace. This will help understand which extinguisher you will need to put out any fire.
It’s important to buy the correct extinguisher, and the right amount for the space. This may also mean you have more than one stored, particularly in a large industrial kitchen or factory.
Fires occur when the fuel being burned (such as paper) reaches a certain core temperature which causes a fire to ignite.
What is a Class A Fire?
Class A involves solid materials such as wood, paper, plastics, coal, furniture and fabrics. An easy way of identifying a Class A fire is to see if ash is being produced.
Class A fires happen when a solid fuel combines with both oxygen and heat to ignite and cause flames. All 3 of these elements in the triangle are required and without one or more of them, there will be no fire.
A good example of a Class A fire is to think of a bonfire, BBQ, or rubbish pile. The solid is ignited when both heat and oxygen are present and reach high temperatures.
Common Causes of Class A Fires
In factories or offices, stored cardboard and paper is a common cause of workplace fires. The presence and storage of such flammable materials should form part of a workplace fire risk assessment.
Another common cause of a Class A fire in the workplace can be used cigarettes placed in a bin. Smokers may have a bin for disposing of their cigarettes once smoked and if there is anything solid in the bin, the cigarette then has the potential to cause a fire.
Class A fires can spread quickly depending on the fuel being burnt. Some fabrics, for example, are extremely flammable and can catch fire and spread at an alarming rate. Often these types of fires begin in very dry conditions which can mean the fire created is more extreme.
Class D fires are also caused by solids but should not be confused with Class A. They are primarily caused by combustible metals and need different measures to extinguish them than Class A fires.
Further reading: What fire extinguisher for paper fires?
Class A Fire Symbol
Class A fire symbols will have the Letter A in the right-hand side corner followed by an image of logs burning with flames above.
About Class A Fire Extinguishers
When dealing with a Class A fire you need to use water as this is the most effective way of eliminating the heat source from the fire.
If there are no electrics present, buckets of water, a fire hose, and also a water fire extinguisher can be used to extinguish this type of fire. Once water is applied to a Class A fire, it reduces the heat and will put out the flames.
Other extinguishers you can use in the event of a Class A fire include:-
See Also: Extinguisher Colours – an identification guide for different types of fire extinguisher.
How to Use a Water Extinguisher
It’s important to first assess the size of the fire and if you feel able to put it out. No one should be taking unnecessary risks and sometimes the only option will be to call the fire brigade.
If you feel it’s safe, stand steady on two feet and deploy the extinguisher at a safe distance. Move slowly forwards as the fire starts to die. Once the fire is out you should ventiliate the area.
Other Types of Fire Extinguisher
There are other extinguishers which will be effective when dealing with an A class fire.
Foam Fire Extinguishers
You can use foam fire extinguishers on Class A fires. These work by tackling the oxygen supply of the fire, eventually suppressing it enough for the fire to die out.
Dry Powder Fire Extinguishers
Dry powder fire extinguishers react to fires in the same way as foam and remove oxygen from the fire triangle.
However, this type of fire extinguisher can cause a damage to the fabric of the building. Powder extinguishers contain corrosive and abrasive materials. They should only be used as a last resort on Class A fires.
Water fire extinguishers are suited to Class A fires only and should not be used on other fire types.
Types of Extinguishers That Should Not Be Used
Water is best for these fires but you can use any of the options listed within this article. The only time you should refrain from using water is if you suspect electrics may be involved.
Class A Fire Prevention
Of course, prevention is key when it comes to fire safety so have a read of our tips below.
- Be sure to recognise any materials susceptible to burning and keep these away from any potential source that will ignite them.
- Don’t let solid materials clutter up spaces and have a regular clean of all areas where paper, plastic, and cardboard are kept.
- Don’t have candles in offices and other work environments.
