Portable Fire Exinguishers

When should you attempt to fight a fire with a portable fire extinguisher?

  • If you are trained
  • If you are capable
  • If you are willing
  • If you know what's burning
  • If an appropriate, fully charged, fire extinguisher is available
  • If the fire has already been reported
  • If you can fight the fire safely
  • If you have a clear exit path behind you

The National Fire Protection Association (NFPA) standard #10 establishes the criteria for portable fire extinguishers. NFPA categorizes fires as follows:

  • Class A Fires – Fires involving ordinary combustibles such as paper, wood, cotton, and certain plastics.
  • Class B Fires – Fires involving flammable liquids.
  • Class C Fires – Fires involving energized electrical equipment
  • Class D Fires – Fires involving combustible metals such as magnesium, sodium and aluminum. 
  • Class K Fires – Fires involving combustible liquids specifically cooking oils.

 There are five basic types of portable fire extinguishers, each is designed to extinguish a specific type of fire, A, B, C, D or K. The type of fire that an extinguisher is designed to suppress is listed on the label of the extinguisher. Newer fire extinguishers also use pictures on their labels to show what kinds of fires they are effective on.

Many extinguishers have multiclass ratings. An extinguisher rated ABC is designed to suppress A, B, and C fires. Besides the alphabetical rating, Class A and Class B portable fire extinguishers also have a numerical rating. This numerical rating describes the extinguishing potential of a given size extinguisher.

Most of the portable fire extinguishers found on the campus of the University of Arizona are rated ABC and contain a dry chemical fire extinguishing agent. Some of the laboratories on campus have extinguishers rated BC and may contain carbon dioxide as the extinguishing agent.

Fighting a fire with a portable fire extinguisher is NOT in the job description of most employees at the University of Arizona. If you choose to fight a fire with a portable fire extinguisher, remember the following steps:

  • Call 9-1-1 or activate a fire alarm pull station.
  • Grab the fire extinguisher, if it is in a cabinet with a glass window, use a heavy object to break the glass, DO NOT USE YOUR BARE HAND.
  • Remember P.A.S.S.
    • P - Pull the pin on the extinguisher handle.
    • A - Aim the nozzle towards the base of the flame.
    • S - Squeeze the handle to discharge the extinguishing agent.
    • S - Sweep the nozzle back and forth at the base of the fire.

The Department of Risk Management Services at the University of Arizona offers training to employees on the use of portable fire extinguishers. Contact Jeff Warren at 621-2921 or jeffreyswarren@email.arizona.edu for more information.

Link: OSHA