What Are The Different Classes of Fire?

What Are The Different Classes of Fire?

In 2012, one structure fire was reported every 66 seconds and one outside fire was reported every 46 seconds.  There were 1,375,000 fires reported in the United States in 2012 costing over $12.4 billion in property damage.  To break down the stats, there were 480,500 structure fires, 172,500 highway fires and 692,000 outside and other fires.  These statistics from the NFPA Fire Analysis & Research are extremely eye opening.

What exactly is a fire? A fire is caused by a chemical reaction involving a fuel, heat, and oxygen. However, not every fire is the same.

United States fire professionals classify fires into 5 different types/classes: A, B, C, D, and K. Each of these fire types require different ways to extinguish the fire. AKE Safety Equipment  feels that it is highly important to educate families about the different types of fires as well as fire safety.

Described below are the 5 fire classes of fire:

Class A Fire

Class A Fires are started by ordinary combustible materials such as wood, cloth, paper and some plastics. These types of fire leave an ashy residue. The best way to extinguish this type of fire is by removing the heat source.

Class B Fire

Class B fires are fueled by flammable or combustible liquids, flammable gases, tars, oils, oil-based paints, solvents, lacquers, alcohols, kerosene and petroleum greases.  This type of fire actually burns on the surface of the fuels. Class B fires are fast moving and can engulf a large area in a short amount of time. Smoldering or blanketing the fire source is the best way to extinguish this type of fire. Water should not be used to extinguish this type of fire.

Class C Fire

Class C fires involve electricity and electrical equipment. This fire would also be extinguished by blanketing or smothering the fire source with a non-conducting extinguishing agent. Make sure to turn off the source of electricity as soon as possible if a fire does occur. Water should not be used to extinguish this type of fire.

Class D Fire

Class D fires involve combustible metals and metal alloys. These would include metals including magnesium, titanium, zirconium, sodium, lithium, and potassium. These fires typically occur in manufacturing or chemical laboratories and are rare outside of these environments. The only way to extinguish Class D fires is by an agent specific to the type of metal on fire. Water and most other extinguishing methods should not be used to extinguish a Class D fire.

Class K Fire

Class K fires occur in commercial kitchens. They involve combustible cooking agents such as vegetable oils. Water should not be used to stop this type of fire.



University of Pennsylvania Division of Public Safety