- Fires can be classified in five different ways depending on the agent that fuels them
- Using water on some fires, like Class B and C fires, can actually make them more dangerous.
- If a fire can’t be put out, leave the area as quickly as possible and alert everyone nearby. Contact emergency services as soon as you can safely do so.
When faced with a fire, knowing how to extinguish it can come in handy. That being said, always use your best judgment and proceed with caution, especially because when it comes to extinguishing a blaze, identifying the type of fire can be incredibly important.
Here’s how to put out the most common types of fires and which fire extinguishers to use for each.
There are actually five main types of fires.
Most of us probably don’t think much about the distinction between different types of fires, but knowing the difference could be life-saving.
Fires can be classified in five different ways depending on the agent that fuels them: Class A, Class B, Class C, Class D, and Class K.
Each type of fire involves different flammable materials and requires a special approach. In fact, trying to fight a blaze with the wrong method might make the situation worse.
In most cases, knowing which type of fire extinguisher to use is crucial. Fortunately, using one can be pretty simple – the Fire Equipment Manufacturers’ Association suggests remembering the acronym “PASS”: Pull the pin, aim the nozzle from a safe difference, squeeze the handle slowly, and sweep the nozzle from side to side until the fire is out. When using an extinguisher, you’ll want to aim low at the base of the fire.
That being said, if you keep a fire extinguisher in your home or place of work, you’ll want to check its gauge monthly and be sure it is in working condition, Atlanta fire chief Dennis L. Rubin told Real Simple. You’ll also want to check the extinguisher for damages and get it inspected if necessary. The worst time to find out your fire extinguisher’s pressure is too low is when you need it the most.
Most importantly, you’ll want to use the proper extinguisher when putting out a fire.
Class A fires are the easiest to put out. They involve solid materials like wood, paper, plastic, or clothing.
Class A fires are the most common type of fire and the kind that most of us are familiar with. They involve solid combustible materials such as wood, paper, cloth, trash, or plastic.
You might start Class A fires intentionally when lighting a match or starting a bonfire. An unintentional Class A fire could result from knocking over a candle, a stray spark from a fireplace, or a lightning strike on a tree.
Luckily, Class A fires are the easiest type to extinguish. The Fire Equipment Manufacturer’s Association recommended using a water or foam fire extinguisher on Class A fires. You can also use water to douse the fire, as it can remove the fire’s heat supply.
Class B fires involve flammable liquids like oil, alcohol, or gasoline.
According to the US Fire Administration, Class B fires involve ignitable liquids or gases like petroleum grease, alcohol, paint, propane, or gasoline. But, this classification typically does not include fires involving cooking oils or grease.
According to Strike First, these types of fires might occur anywhere flammable liquids or gases are stored or used.
It’s very important not to use a water extinguisher on a Class B fire – the stream of water might spread the flaming material rather than extinguish it.
Class B fires should be extinguished using foam, powder, or carbon dioxide extinguishers, according to the Fire Equipment Manufacturer’s Association. These types of extinguishers work by cutting off a fire’s oxygen supply.
Class C fires involve a source of electricity.
Class C fires, referred to as Class E in Australia, involve electrical equipment. This type of fire might be started by old wiring in walls, frayed electrical cords, worn-out breaker boxes, or faulty appliances.
Electrical fires are very common in both homes and industrial settings. According to Strike First, the first thing you should try to do if an electrical fire starts is to disconnect the appliance or item from its power source only if it is safe to do so.
If possible, you should try to extinguish the flames using a carbon dioxide or dry powder fire extinguisher. If and when the power source is disconnected, the fire can become a different class of fire, typically Class A.
Do not try to put out an electrical fire with a water or foam extinguisher, as both of those materials can conduct electricity and potentially make the situation more dangerous.
Class D fires are rare, but can happen when a metal ignites.
It takes high levels of heat to ignite most metals, which makes Class D fires pretty rare outside of laboratories and industrial settings. According to University of Massachusetts Boston’s Office of Environmental Health and Safety, Class D fires are oftentimes caused by alkali metals such as potassium, magnesium, aluminium, and sodium, as these can ignite when exposed to air or water.
Although you’re unlikely to face a Class D blaze in your home, the Fire Equipment Manufacturer’s Association advised extinguishing these types of fires with a dry powder extinguisher only.
Dry powder extinguishers work on metal fires by separating the fuel from oxygen or removing the heat element of the blaze, but foam or water extinguishers can potentially increase the intensity of the flames and cause dangerous explosions, according to Imperial Systems.
Some fires might also be termed Class K or Class F if they involve cooking oils such as vegetable oil or animal fats.
Although they are sometimes lumped in with Class B fires, the US Fire Administration considers blazes involving cooking oils to be in their own category, typically referred to as Class K or Class F in the UK.
Because of the high flash point of cooking oils and fats, Class K fires often start when a pan is left unattended for too long on a stove. If possible, you’ll want to turn off the heat on your cooking appliance and remove the fire from the heat source as soon as possible.
Just as you shouldn’t use water to try and extinguish a Class B fire, dousing a cooking oil fire with liquid is likely to create a dangerous splatter effect and spread the flames.
Instead, you should extinguish a Class K fire with a wet chemical extinguisher, according to the New York City Fire Department. These are mandatory in many commercial kitchens and are a good investment if you do any amount of cooking at home.
Here’s what to do if you can’t extinguish a fire.
If you have any doubt at all about your ability to quickly and safely extinguish a fire, you should immediately evacuate. According to the Department of Homeland Security, it can take just 30 seconds for a small flame to turn into a major blaze.
In the event of a fire, the Red Cross recommended leaving the area or building as quickly as possible after yelling to alert anyone nearby. Always use stairs rather than elevators, stay low to the ground, and use the back of your hand to feel if closed doors are warm to the touch, as you should never open doors that do not feel cool. Call 911 or your local emergency number as soon as it is safe to do so.
If your clothes catch on fire, the Red Cross suggests you drop to the ground and cover your face before rolling back and forth until the flames go out.
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