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How Fire Extinguishers Work and Are Tested

Updated February 2020

When it comes to a building’s fire protection systems, fire extinguishers are often the unsung hero. Due to local and national fire code requirements, fire extinguishers are commonplace for most buildings but usually take the back seat to fire alarms and sprinklers when it comes to the common ideas about fire mitigation. In fact, most people lack education about how fire extinguishers work and what is required to test them properly. Read on to learn more about how fire extinguishers work and how they can protect your business.

Building Owners Should Never Overlook Fire Extinguishers When Preparing for an Inspection

Building owners should know that disregarding their fire extinguishers in the preparation for a fire inspection could leave the building vulnerable to an inspection failure – and more importantly, it could leave the building severely unprepared in the event of an electrical fire or other types of fire.

Here at Allegiant Fire, we know all too well that a fire extinguisher is a building’s first line of defense if a fire breaks out. That’s why we think it is so important that our clients understand how to operate their fire extinguisher equipment, what regulations they are subject to, and what can be expected when their systems are tested.

Fire Extinguisher 101

To operate your fire extinguisher, the National Fire Protection Agency (NFPA) recommends you follow the easy-to-remember acronym, PASS:

  • Pull the pin. Hold the extinguisher with the nozzle pointing away from you, and remove the pin from its place between the handles.
  • Aim and point the extinguisher nozzle at the base of the fire.
  • Squeeze the top and bottom handles evenly.
  • Sweep the nozzle from side-to-side, aiming the extinguishing agent at the base of the fire.

**It’s important to remember that portable fire extinguishers save property and lives, but they are only designed to put out small fires or contain a fire until the fire department arrives. If the fire is large and spreading rapidly, the number one priority is to get out safely and unharmed.

Understanding Fire Extinguisher Types and Classes

There are four common types of fire extinguishers that are classified into four groups – A, B, C and D. Each type is designed to put out different types of fires.

  • Class A extinguishers will put out fires fueled by ordinary combustibles like wood and paper
  • Class B extinguishers are for use on flammable liquids like gasoline, grease, or oil
  • Class C extinguishers are only designed for use on electrically energized fires
  • Class D extinguishers are best for use with flammable metals

There are multipurpose extinguishers that can be used on different types of fires. These multipurpose units will be labeled with more than one class, like A-B, B-C or A-B-C.

Fire Extinguisher Regulations

There are a few requirements a building owner should consider when choosing and installing a portable fire extinguisher. Your local fire department or authority having jurisdiction can help advise what extinguisher you need. Some variables that will likely be assessed when choosing the correct extinguisher include:

  •  Size of building/floors
  •  Types of fire hazards in the building
  •  Fire extinguisher accessibility and placement
  •  Type of business being held

Fire Extinguisher Testing

The National Fire code requires that building owners have their fire extinguishers certified by a licensed service person. Annual maintenance is required for any extinguishers in industrial and commercial applications. Depending on the type of extinguisher they are subject to pressure testing and internal inspections. Having your extinguishers inspected regularly is important to verify they are full and in proper working order. Many authorities and insurance companies also require monthly extinguisher checks to be performed by the building owner.

The professionals at Allegiant Fire Protection help take the guesswork out of fire safety compliance.  Our certified technicians will complete all required tests and inspections and update the fire extinguisher tags. We can also train your employees in proper fire extinguisher usage. To learn more about our services or to schedule any Fire and Safety Equipment Testing and Inspections, don’t hesitate to give us a call at (630) 348-9636 or visit us at We are standing by today for your fire preparedness questions and concerns!

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