What Are the Different Classes of Fires?

The Importance of Understanding Fire Classes

Fire is fire, right?

No. The cause of a fire and the flammable materials involved affect it differently. Different environments produce different types of flames and various dangers. They can also burn at higher or lower temperatures than usual.

But most importantly, different types of fires require different fire suppression methods. Class A fires are the most common and can be extinguished with various means, including water. However, if you try to use water to put out a grease fire (Class K), it could accelerate the spread of flames and worsen the situation.

If you want to extinguish or suppress a fire, you need to know its classification and the best method of suppression.

Types of Fires

Here are some of the most common types of fires:

• Class A Fires. Class A fires are very common because they involve ordinary materials such as wood, paper, fabric, trash, rubber, and even plastic. Water works perfectly for these fires. Dry chemical agents and certain types of foam can also be used.
• Class B Fires. Class B fires occur due to flammable liquids and solvents such as paint, varnish, oil, and gasoline. Water is not suitable here; dry chemical extinguishers, carbon dioxide, or certain types of foam can be used for suppression.
• Class C Fires. Class C fires originate from electricity. Wiring, equipment, and motors can cause a fire due to malfunction or damage. These fires should be extinguished with dry chemicals, halogen compounds, or carbon dioxide devices.
• Class D Fires. Class D fires are less common as they involve flammable metals such as magnesium, titanium, and lithium. The only effective solution is a dry powder.
• Class K Fires. You might think the next type of fire is Class E, but actually it's Class K, named because it often occurs in commercial kitchens. This class of fire starts from cooking materials such as grease or oil. Wet chemical extinguishers are ideal for these.

Note that these fire classes may be labeled differently in various countries or using different systems. However, flammable materials can be viewed consistently regardless of how they are grouped or named; for example, it's always dangerous to extinguish a grease fire with water.

Additional Tips for Handling Various Fire Classes

You can also follow these tips to properly handle different fire classes:

• Install a fire suppression system in advance. At the moment of a fire, it's hard to recall all correct and incorrect approaches for preventing or fighting one. That’s why many homes and businesses install fire suppression systems that typically activate automatically upon detecting smoke or fire. You can choose a system suitable for the most likely types of fires in advance.
• Call for help first. If a fire occurs in your home or business, you might be tempted to immediately start fighting it. Instead, it's better to call the fire department (if not automatically triggered). This ensures a quick response from professionals and gives you added protection if your initial suppression methods prove ineffective.
• Use fire extinguishers only with proper training. Fire extinguishers can be helpful in limiting the spread of small fires, but they can also be dangerous—especially if you use the wrong type for a specific fire. Only use an extinguisher when you know how to properly operate it and are confident in your ability to apply it.
• If a fire is unclear, don't take risks. There are situations where you do not know the exact cause of a fire or the flammable materials involved. In such cases, it’s better to proceed cautiously and avoid using random materials for suppression.

You don't need to memorize or fully understand the different classes of fires unless you're responsible for a safety program. Instead, just remember that different fire classes require completely different approaches—and only use fire extinguishers or suppression systems when you know what you're doing.