Sources & Types of Fires

Fires are chemical reactions that occur when fuel, oxygen, and an ignition source combine. Fire extinguishers work by removing one or more of these sources, with different extinguishers working in different ways. For example, water extinguishers remove the heat, and CO2 extinguishers remove the supply of oxygen. Many fire extinguishers are designed for use on specific types of fires. First, determine the fire's fuel source. Knowing the fuel source places the fire in a certain class, which assists with choosing the correct size and type of extinguisher. There are several classes of fire, as follow:

• Class A fires involve ordinary combustible materials, such as paper, wood, cloth, and some rubber and plastic materials.
• Class B fires involve flammable or combustible liquids, flammable gasses, greases, and similar material, along with some rubber and plastic materials.
• Class C fires involve energized electrical equipment where safety to the employee requires the use of electrically nonconductive extinguishing media.
• Class D fires involve combustible materials, such as magnesium, titanium, zirconium, sodium, lithium, and potassium.

To learn more about Fire Extinguishers visit our Portable Fire Extinguishers Online Training web page.