Lesson 3: Fire Classifications

Glossary

Types of Fires

Fires are often classified according to the fuel type and origin.  It's important to know the different classes of fire in order to determine how best to extinguish them.

There are 4 types of fires, referred to as Class A, Class B, Class C, and Class D.  Click below each of the pictures (©iStock), to help you understand more about each class of fire.

 
Class A



  • Class A fires usually burn wood, cloth and/or paper.
  • These fires are normally put out by water; water reduces the heat.

 
Class B



  • Class B fires are caused by burning flammable liquids such as grease, gasoline, and lubricating oils.
  • The safest way to control these fires is to remove the fuel source and allow the fire to burn itself out.
  • Class B fires are very dangerous because flammable liquids float on water and are also heavier than air; this can cause the fire to spread or cause an explosion.

 
Class C

                 

  • Class C fires occur in live electrical equipment.
  • Electrical power sources must be turned off before attempting to fight the fire.
  • Spraying water on electrical fires is dangerous because the water will conduct electricity and could injure or kill anyone coming in contact with it.

 
Class D




  • Class D Fires occur in combustible metals such as magnesium and sodium.
  • Spraying water on these metals is dangerous; water reacts chemically with the metals and increases the strength of the fire.


Class K

A class K fire, a sub-category of a Class B fire, includes cooking oils or fats.
Some examples, of a Class K  fire, are:                                                                   
 
  • a pan igniting, after being left unattended
  • a grease fire in a commercial kitchen

Class K fires burn hot and produce damaging smoke if not controlled quickly.

Putting water on a Class K fire will spread the oil, which in turn will spread the fire.