The Ultimate Guide To Fire Extinguishers

Do you know how to use a fire extinguisher?

It should be no surprise that every commercial and industrial space needs to be equipped with fire extinguishers to arm personnel with life-saving equipment. 

But it’s not enough to know this simple point. It’s imperative to understand the different types of fire extinguishers, how to use them, and how to maintain them.

In this guide, you will learn

  • What extinguisher to use depending on the type of fire
  • How to use a fire extinguisher
  • How to store fire extinguishers in the workplace
  • The maintenance schedule and inspection process to upkeep fire extinguishers
The Ultimate Guide to Fire Extinguishers

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Types of Fire and Fire Extinguishers

Many people do not realize that there are different types of fire, let alone which type of extinguisher to use in a given situation.

To determine the type of extinguisher needed, it helps to have a basic understanding of the five main Classes of fire that you could encounter.

Types of Fire

  • Class A - Everyday combustible materials (paper, wood, cloth)
  • Class B - Flammable liquid or gas (grease, gasoline, oil)
  • Class C -  Energized electrical equipment (appliances, tools)
  • Class D - Combustible metals (titanium, zirconium, magnesium)
  • Class K - Cooking oils and grease (vegetable oil, animal fat)

Many fire extinguishers are labeled with clear pictures indicating what Class the extinguisher is suitable for, while some older versions may only be indicated by the Class letter.

No matter the Class, fires always comprise the same four elements: fuel, heat, oxygen, and chain reaction. Portable fire extinguishers are designed to extinguish a fire by removing one or more of these elements. However, it’s essential to keep in mind that not all fire extinguishers can extinguish all Class of fires, and some may even cause more damage and harm to the operator than help extinguish the flames.

Err on the side of safety and always keep specific extinguishers on hand for likely scenarios, like a Class K extinguisher in a kitchen and Class B in a garage.

Having the right type of fire extinguisher for your needs is critical to protecting lives and assets.

Having the right type of fire extinguisher for your needs is critical to protecting lives and assets.

Here are the important considerations to keep in mind when choosing the right fire extinguisher. Learn More →


Simply knowing the Class of fire and using an appropriate extinguisher is all that is needed to save lives in an emergency where fighting a fire is feasible. Using the incorrect agent can allow the fire to reignite after successfully extinguishing. The next step is choosing a suitable extinguisher for your environment. Different extinguishing agents should be considered to determine the correct fire extinguisher for your specific application.



As denoted by the name, these extinguishers are effective for Class A, B, and C fires, and therefore are standard extinguishers to find in many different environments. Dry chemical fire extinguishers put out the fire by primarily interrupting the chemical reaction of the fire. 


These extinguishers use pressurized carbon dioxide (CO2) to remove oxygen from the fire, eliminating an essential element needed for fires to burn. CO2 extinguishers are primarily used in Class B and C fires and require no cleanup.


Specialized for Class K fires, these fire extinguishers use a new agent that extinguishes the fire by removing the heat from the fire and preventing re-ignition by creating a barrier between the oxygen and fuel elements. A wet chemical of Class K extinguishers was developed for modern, high-efficiency deep fat fryers in commercial cooking operations.


These fire extinguishers apply a spray of water, which rapidly lowers the temperature of the fire. Water mist extinguishers are primarily for Class A fires, although they are safe to use on Class C fires.


These extinguishers propel a foam solution that expands when it hits the air, cooling the fire and coating the combustible fuel, creating a barrier from oxygen. Foam extinguishers are suitable for Class A and B fires.


Commonly used on Class B and C fires, clean agent extinguishers utilize gaseous fire suppression - meaning no cleanup - by reducing the oxygen levels near the fire and stopping the chain reaction needed for the fire to continue to burn.


This specialized extinguisher works similarly to dry chemical extinguishers by using a powder to separate oxygen from the fuel. However, these extinguishers are only suitable for Class D or combustible metal fires. They are ineffective on all other Classes of fire.

If you’re unsure about what type of fire extinguisher you need to have available in your workplace, it’s best to consult a company that specializes in fire safety equipment to be sure you’re well prepared.

How to Use a Fire Extinguisher

When using a fire extinguisher, remember to always P.A.S.S. (pull, aim, squeeze, sweep).

Proper use of a fire extinguisher in an emergency is key to extinguishing or containing a fire until emergency services arrive on the scene. To learn how to use a fire extinguisher, follow the steps below.

  1. PULL out the safety pin.
  2. AIM the nozzle or hose at the base of the fire from the recommended safe distance specified on the extinguisher tank.
  3. SQUEEZE down on the operating lever to discharge the fire extinguishing agent.
  4. SWEEP the nozzle or hose from side to side until the fire is out. Move forward or around the fire area as the fire diminishes. Watch the area in case of reignition.

PASS - Pull, Aim, Squeeze, Sweep

To avoid trapping yourself in a dangerous situation, make sure to keep your back to an accessible escape route to use should the fire become too large to extinguish or too dangerous. Remember that smoke from a fire - not just the flames - can be hazardous and even deadly. Portable fire extinguishers are effective against small fires, but if the flames are overwhelming, you need to evacuate the building and call 911.

Proper Fire Extinguisher Maintenance

Maintenance Schedule 

According to the National Fire Protection Association (NFPA), fire extinguishers must be maintained annually and inspected monthly to ensure that they are in good operating condition in case of an emergency. Many companies have trained staff who can perform the monthly inspections, while annual maintenance and functionality testing are best left to a safety technician.

Carbon dioxide and water-based extinguishers need a hydrostatic test every five years. Stored-pressure extinguishers require standardized maintenance every six years, and stored pressure and cartridge-operated extinguishers need a hydrostatic test conducted every 12 years.

The NFPA requires fire extinguishers to be maintained annually and inspected monthly.

Inspection Process

Performing monthly inspections is a quick yet crucial process in an organization’s overall health and safety plan. When performing these inspections, a third-party provider will complete the following:

  • Reference the list of fire extinguishers in the building to ensure they are all accounted for when performing the inspections.
  • Determine if the extinguisher is hung correctly and remove it from its hanger.
  • Ensure the fire extinguisher has a valid maintenance tag and check the date of manufacture, last hydrotest, and six-year maintenance date.
  • Check the pressure gauge to ensure the extinguisher is charged and ready for immediate use. Also, at this time, check the condition of the indicator and its compatibility with the extinguisher. Some fire extinguishers, including cartridge-operated extinguishers, don’t have gauges and instead will have an indicator that should be depressed if it is ready to use. A carbon dioxide (CO2) extinguisher does not have a gauge or indicator and will need to be weighed to make sure it is full. If the weight matches the weight on the tag, it is full and ready to be used.
  • Check the valve and shell for damage or corrosion, and check the valve opening for powder or any foreign matter.
  • Remove the hose, inspect the threads for cracks or splits, and inspect the condition of the discharge horn.
  • Remove the extinguisher seal and locking pin, and check the upper and lower handles, making sure the tamper seal is on the extinguisher, undamaged, and that it’s holding the pin in firmly before replacing the locking pin and resealing the extinguisher.
  • For dry extinguishers, fluff the powder by turning the extinguisher.
  • Be sure the extinguisher classification corresponds with the potential hazard in the environment and that it is not blocked or obscured from visibility in the room.

Once the inspection is complete, clean the extinguisher, return it to its hanger, and sign and date the service tag to record the inspection. Additionally, the business should receive a complete report of the inspection explaining any deficiencies and recommending corrective action by recognized codes for care and maintenance.

How to Store Fire Extinguishers

Fire extinguishers should always be readily accessible and visible in the event of a fire. This means they shouldn’t be blocked by cleaning supplies, tucked in the back of storage closets, or locked away in rooms only certain personnel can access. Here are a few things to keep in mind when deciding where to place fire extinguishers:

  • Keep areas in front of fire extinguishers clean and clear of obstructions.
  • Mount fire extinguishers in such a way that they can’t be mistakenly moved or damaged.
  • Mount extinguishers, so the carrying handle is between 3.5-5 feet from the floor to allow universal accessibility.
  • Install a sign or other means of identification above a portable fire extinguisher.
  • Mount the indicator sign to not be blocked by equipment or other obstructions.
  • For particularly dirty worksites, protect fire extinguishers with a removable cover.

Where fire extinguishers should be placed around the workplace depends on the location of potential hazards, the size of the area, and the type of extinguisher.

With this in mind, it’s essential to check the maximum travel distance required by code. This refers to the farthest distance a person should travel before reaching a fire extinguisher and can be determined by the Class of extinguisher and the potential hazard type.

It’s also essential to ensure that fire extinguishers are stored in the proper position and temperature. Though newer extinguishers can be stored on their sides, adequate storage is recommended, including appropriate mounting brackets to keep the extinguisher upright and in easy acces

Most modern extinguishers can be stored in a wide range of temperatures — from about -40° F to 120° F — so temperature likely won’t be an issue. However, in extreme low-temperature conditions, the extinguisher valve or hose could crack, leaving the extinguisher unusable, so be sure not to allow the extinguisher to freeze.

Simple Answers to 5 Common Fire Extinguisher Location Questions

Simple Answers to 5 Common Fire Extinguisher Location Questions

Fire extinguishers need to be readily accessible by employees in the event of a fire. Here are simple answers to five of the most frequently asked fire extinguisher location questions for businesses. Learn More →


Proper knowledge of how to operate fire extinguishers in the workplace can save lives and company assets in the event of a fire and arm employees with the confidence they need to feel safe. It’s essential to meet that knowledge with regular extinguisher inspections and maintenance and provide the appropriate type of extinguisher for each potential hazard. Combined, these aspects create a protected and prepared workplace.

Are your workplace and employees prepared in case of a fire?

Learn more about our preventative maintenance program.

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