Did you know there are five different types of fires, classified based on what fuels them?
If you don't, you should take a moment to learn - because if you try to put certain types of fires out with water, you can actually make them worse!
Keep reading to learn about each of the five different types of fires, their fuel sources, and most importantly, how to extinguish each type.
Class A Fires
Class A fires are the most common, and the easiest to put out. They are fueled by general combustible materials like paper, wood, plastic, and fabric.
Class A fires are straightforward - a spark lands on a flammable material and the fire starts. It consumes other nearby flammable materials and continues to grow as long as there are oxygen and available fuel to feed it.
Common scenarios include knocked over or forgotten candles, a spark from a fireplace jumping out of the grate, lightning striking a tree, or small controlled burns, such as yard waste, getting out of control.
To extinguish one of these fires, the Fire Equipment Manufacturer's Association recommends a water or foam extinguisher. If you don't have an extinguisher, you can also use whatever available water source you have.
Sometimes these fires can be smothered if they are small enough. A good example of this would be the stop, drop and roll method taught to young children. Rolling the fire on the ground cuts it off from oxygen and smothers the flames.
Class B Fires
Class B fires involve a flammable liquid. This includes oil, petroleum grease, alcohol, paint, propane, gasoline, and other types of liquid fuels. This class doesn't generally involve cooking oils, which have their own special class.
These fires can start anywhere these flammable liquids are kept, but are most common in garages, basements, and commercial businesses.
The most important thing to note about Class B fires is that a stream of water sprayed onto the flames will likely spread the fire rather than extinguish it.
Most of these liquids don't mix with water. Meaning a jet of water sprayed across the flames, as recommended for Class A fires, will actually push the liquid farther away. As it's the liquid itself that is on flames, the fire will move with the liquid.
Only use foam or powder extinguishers that contain carbon dioxide to attempt to extinguish a Class B fire.
Class C Fires
Class C fires are also called electric fires, and as the name suggests, they involve electric components.
These fires most commonly start from old wiring, electrical cords that have been cut or frayed, faulty electrical appliances, or breakers that have failed.
These fires are common in both residential and commercial settings, and can happen anywhere electricity is present. If an electrical fire starts, your first step should be to try to disconnect any appliance or electrical component involved, if you can safely do so.
To extinguish a Class C fire, use a dry powder or carbon dioxide extinguisher. A water or foam extinguisher is dangerous to use near electric fires, as both conduct electricity. In other words, you could attempt to put out the fire only to be electrocuted.
If the source of electricity is removed from the equation, for instance, if you're able to unplug the appliance that caused it, the fire can then typically be considered a Class A fire.
Class D Fires
Class D fires are rare and generally only happen in commercial applications. These fires involve the ignition of a metal.
Most of these fires are confined to laboratories and industrial manufacturing. Alkali metals like magnesium, potassium, sodium, and aluminum can ignite when they come into contact with oxygen or water.
While you likely won't come into contact with these fires, if you are confronted by one only use a dry powder extinguisher. Water and other chemicals included in traditional extinguishers can intensify the flames through further chemical reactions.
Dry powder extinguishers separate the flames from their fuel source.
Class K Fires
Class K fires, sometimes called Class F fires, are special fires that involve cooking oils derived from both plant and animal sources.
These fires typically start, as you would guess, in cooking applications. Cooking oils and fats have a high flash point, meaning the oils can spontaneously ignite at a certain temperature.
If a pan is left on the stove unattended or oil spills down into the burner, you could have a Class K fire on your hands.
A wet chemical extinguisher is recommended for these fires. Water will spread the flames and can cause a splatter effect, injuring anyone nearby when hot oil jumps around.
Class K fire extinguishers are mandatory in commercial kitchens.
The Different Types of Fires
Unfortunately, in the event of a fire, you're probably not going to be thinking clearly about the different types of fires and what you should use. Nor do most people keep multiple classes of fire extinguishers on hand.
Luckily, there are extinguishers available today that are able to safely extinguish multiple kinds of fire. Check out our fire extinguisher comparison chart to learn more!