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#66 -- Ultimate Guide to Fire Extinguisher Types: Servicing and Uses

Posted by Jason Hugo and Anna Hartenbach on 6/8/2017 to Fire Extinguishers
Fire extinguishers are a staple in homes, offices, and commercial buildings across the country. Generally used to put out or extinguish small fires, fire extinguishers are the real superhero in times of an emergency!

One important factor to remember is that fire extinguishers are not a “one size fits most” tool. There are different sizes and types of fire extinguishers. Like any decision, there are certain factors to take into consideration when selecting a fire extinguisher to purchase for your home or business. 

In this article, we’re going to explore that topic more – to help you understand the various types of fire extinguishers and their uses. We’ll discover how many classifications there are, learn what the numbers mean, and how often they should be serviced or repurchased. We’ll wrap up by learning how a fire extinguisher works and how to use them correctly. Sound good? Then continue reading!

Not what you’re looking for? Feel free to click here to view our selection of fire extinguishers.

How many fire classifications are there and what are the types?

You might be surprised to learn that there are different types of fires – five different kinds. A fire’s type is dependent upon its fuel element, which determines the type of extinguisher needed to put it out. 
  1. Class A – Ordinary combustibles such as wood, paper, cloth, trash, and plastics. 
  2. Class B – Flammable liquids like gasoline, petroleum, oil, and paint or gasses like propane and butane. This class excludes grease and cooking oils.
  3. Class C – Energized electrical equipment like appliances, transformers, and motors. The electric must be turned off to aid extinguishing efforts.
  4. Class D – Combustible metals like titanium, magnesium, aluminum, potassium, sodium, and other metals with combustive properties.
  5. Class K – Animal and vegetable fats, cooking oils and greases, and other combustible liquids generally used in food preparation.
How does a fire extinguisher work and how should it be used?

Fire has three essential elements: extreme heat, oxygen (or another type of gas), and fuel. The purpose of a fire extinguisher is to quell one of these elements, thereby extinguishing the fire. Since the contents of the fire extinguisher are dependent on the type of extinguisher, one can only smother the fire if its components match the makeup of the fire. 

Fire Triangle
Photo Caption: Image Source

The extinguisher itself, operates in a similar fashion to an aerosol can because the internal material is compressed with gasses. When the lever is squeezed, it forces the material out using that pressure. An extinguisher should only be used with its designated fire classification. Otherwise, as it propels air towards the fire, the wrong extinguisher will actually cause the fire to spread. 


What are the types of fire extinguishers and their uses?

Fire extinguisher types are dependent on the type of fire:

Water and Foam – Water and foam extinguishers are used in Class A fires only – never B or C because they could cause the flammable liquids in B to spread or increase the shock hazard in a Class C fire. These extinguishers employ foam agents to remove the heat element and separate the oxygen element from the others. 

Carbon Dioxide (CO2) – Carbon Dioxide extinguishers can be used to extinguish Class B or C fires, but are not effective at eliminating Class A fires. These extinguishers remove the oxygen from the fire triangle and infuse a cold discharge to remove the heat element. 

Dry Chemical – Dry Chemical fire extinguishers are multipurpose extinguishers, which use dry chemicals that can be used on Class A, B and C fires. It is the most used type of extinguisher since it can be used on all three types.

Wet Chemical – Wet Chemical removes the heat of the triangle to extinguish the fire and it creates a barrier between the oxygen and fuel to prevent it from re-igniting. For the most part, they’re good for Class K fires from deep fryers, etc. but can be used on Class A fires, too.

Clean Agent or Halogenated – These extinguishers serve mostly in Class B & C fires, but some larger ones can be used on Class A, B and C fires. These extinguishers are more environmentally friendly because they use halocarbon agents that are less depleting to the ozone. Clean agent or halogenated extinguishers remove the heating element from the fire triangle to extinguish fires.

Dry Powder – Like dry chemical extinguishers, Dry Powder extinguishers separate the fuel from the oxygen or remove the heat element to extinguish fires. They are ineffective on all fires except type D, which are combustible metal fires.

Water Mist – Water Mist extinguishers are mostly for Class A fires, but also work safely for Class C fires. They serve as an alternate to Clean Agent extinguishers. They work by removing the heat element.

Cartridge Operated Dry Chemical – This type is another multipurpose dry chemical extinguisher that works for Class A, B, and C fires. Cartridge Operated Dry Chemical extinguishers work for Class A fires by creating a barrier between the oxygen and fuel elements.

All fire extinguishers are labeled to identify their UL classification rating and effectiveness. The Underwriters Laboratory has set standards for extinguishers that determine their classification and the size of fire they are best suited to extinguish. The letter represents the fire class or classes that the extinguisher can be used for and the number is used to show the extinguisher’s effectiveness. It’s important to note that numerical ratings combined with the letters will only appear on class A and B extinguishers. For example, an extinguisher rated 1-A can discharge the equivalent of 1.25 gallons of water and should only be used on class A fires. So the higher the number, the higher the water equivalent. For class B extinguishers, the number is based on square footage. An extinguisher rated 10-B is good for 10 square feet of coverage.


Label
Example: 2A:10B:C

For example, the extinguisher above is a 2A:10B:C. It is the equivalent to 2.5 gallons of water, it can cover 10 square feet, and it is suitable to use on electrical equipment too.

How often should a fire extinguisher be serviced?

Fire extinguisher service requirements depends on its intended use. According to OSHA, fire extinguishers used within the workplace must be inspected and tested annually. An employer must mount and identify extinguishers so that they are accessible to all employees. Furthermore, it’s the responsibility of the employer to train and educate all employees on the use of a fire extinguisher and its associated hazards. Although these OSHA requirements pertain to the workplace, its good practice to have extinguishers inspected annually by professionals wherever they are located. These yearly inspections determine if the extinguisher is safe to operate, if it’s in need of any repairs, or if it needs a hydrostatic test. 

Hydrostatic testing (i.e. a pressure test) is when an extinguisher is put under a higher than normal pressure to determine if it has become weaker over the years. According to the National Fire Protection Association (NFPA), a fire extinguisher must undergo hydrostatic testing every twelve years. A weakened fire extinguisher poses the threat of failure or explosion upon use. 

It’s important to note that rechargeable fire extinguishers are meant to be reused, whereas non-rechargeable extinguishers can only be used once. Although a cheaper option, non-rechargeable extinguishers must be replaced even if they are only partly discharged. For either type, if the seal is broken, it must be serviced. You can tell if your extinguisher is rechargeable by reading its label. 

All fire extinguishers should be outfitted with a paper tag. The main tag used on extinguishers provide the year and month of its last inspection and its expiration date. 

Fire Extinguisher with white tag
A fire extinguisher outfitted with a paper tag

Some extinguishers may also have a second, yellow-colored tag known as a cylinder tag. The cylinder tag tells whether the extinguisher is full, in service, or is discharged or empty – it’s meant to be read from the bottom up, with the top displaying the most current information. 

Fire Extinguisher with a Cylinder Tag
A fire extinguisher with a cylinder tag (image source)

Generally, if an extinguisher hasn’t been serviced for 2-5 years, it should be recharged by a certified dealer. Otherwise, old or unusable fire extinguishers should be disposed of with your local fire department.

How to use a fire extinguisher: Pull, Aim, Squeeze, Sweep

P.A.S.S. is the acronym used to describe the actions to be taken in the event that a fire extinguisher must be used. It’s important to note that before using the extinguisher, you should call 911 or set off the fire alarm, when appropriate. You should also be mindful of an evacuation route so you can escape without being harmed. Even after you have extinguished the fire, do not approach the area in case the fire should reignite. 

P.A.S.S.
Photo Caption: Image Source

P.A.S.S. stands for Pull, Aim, Squeeze, Sweep:
  1. Pull – Pull the pin
  2. Aim – While standing a safe distance away from the fire, aim the nozzle or hose at the base of the fire
  3. Squeeze – Squeeze the handle or lever to expel the extinguishing material 
  4. Sweep – Move from side to side at the base of the fire to smother the flames and if the fire re-ignites repeat steps 2-4

What to Look for When Buying an Extinguisher Online
  • Check to make sure the extinguisher meets your building’s requirements. If you are unsure, check with the authorities having jurisdiction (AHJ).
  • Select the extinguisher type and size based upon the location in which it will be kept. For example, a 10 lb A:B:C extinguisher is good for a larger space like a garage. A:B:C are good for combustibles, flammable liquids, and electrical fires.
  • It should be fully charged, which means the internal elements are under a certain pressure per square inch so that it can propel the material at an appropriate distance.
  • Because fire extinguishers are considered hazardous materials by OSHA, they must be labeled or marked appropriately to ensure their safe transportation from one location to another.

The QRFS Difference

At QRFS we’re ready and waiting to help you with your fire extinguisher needs. We stock ABC Dry Chemical and CO2 fire extinguishers and offer K and Water-Only models. All extinguishers come fully charged and operable. You can select a FREE wall bracket or upgrade to a vehicle mounting bracket.  In addition, you can now order any fire extinguisher cabinet and get the right-sized extinguisher delivered with it – just add the extinguisher option on the extinguisher cabinet page! See our complete selection in the table below: 

ABC Extinguishers:

ABC Extinguisher

With a spray distance ranging from 8-15 feet and in size from 2.5 lb to 30 lb, these completely rechargeable, corrosion resistant extinguishers will exceed your expectations year over year.  

TypeDescription
2.5 lb ABC Dry Chemical Extinguisher 1A:10B:C - ANSI/UL
  • For use on Class A, B, and C fires
  • Weight: 4.5 lbs
  • PSI: 150
  • Range: 8-10 feet
  • Discharge time: 9 seconds
5 lb ABC Dry Chemical Extinguisher 2A:10B:C - ANSI/UL
  • For use on Class A, B, and C fires
  • Weight: 10 1/2 lbs
  • PSI: 195
  • Range: 8-10 feet
  • Discharge time: 13 seconds
5 lb ABC Dry Chemical Extinguisher 3A:10B:C - ANSI/UL
  • For use on Class A, B, and C fires
  • Weight: 10 1/2 lbs
  • PSI: 195
  • Range: 8-10 feet
  • Discharge time: 13 seconds
10 lb ABC Dry Chemical Extinguisher 4A:80B:C - ANSI/UL
  • For use on Class A, B, and C fires
  • Weight: 19 1/4 lbs
  • PSI: 235
  • Range: 10-15 feet
  • Discharge time: 15 seconds
20 lb ABC Dry Chemical Extinguisher 10A:120B:C - ANSI/UL
  • For use on Class A, B, and C fires
  • Weight: 35 1/4 lbs
  • PSI: 235
  • Range: 10-15 feet
  • Discharge time: 28 seconds
30 lb ABC Dry Chemical Extinguisher 10A:120B:C - ANSI/UL
  • For use on Class A, B, and C fires
  • Weight: 50 1/3 lbs
  • PSI: 195
  • Range: 10-15 feet
  • Discharge time: 28 seconds
(Note: Links to all items coming soon)

CO2 Extinguishers:
CO2

With a range of 6-12 feet, a 6-year warranty, and the best valve on the market, CO2 extinguishers from QRFS will meet your specific requirements every time.

TypeDescription
5 lb CO2 Extinguisher 5B:C - ANSI/UL
  • For use on Class B and C fires
  • Weight: 13 1/4 lbs
  • Range: 6-12 feet
  • Discharge time: 10 seconds
10 lb CO2 Extinguisher 10B:C - ANSI/UL
  • For use on Class B and C fires
  • Weight: 28 lbs
  • Range: 6-12 feet
  • Discharge time: 10 seconds
15 lb CO2 Extinguisher 10B:C - ANSI/UL
  • For use on Class B and C fires
  • Weight: 37 lbs
  • Range: 6-12 feet
  • Discharge time: 15 seconds
20 lb CO2 Extinguisher 10B:C - ANSI/UL
  • For use on Class B and C fires
  • Weight: 48 1/8 lbs
  • Range: 6-12 feet
  • Discharge time: 20 seconds
(Note: Links to all items coming soon)

When you make a purchase with QRFS you benefit from our competitive pricing structure and quality customer service – in addition, we handle the additional Hazmat shipping charges for you! 


Still have questions? Leave a comment below and we’ll reply as quickly as possible to get you on the right track!

This blog was originally posted by Jason Hugo and Anna Hartenbach at QRFS.com/blog on June 8, 2017. If you’ve found your fire extinguisher match after reading this, check us out at Facebook.com/QuickResponseFireSupply or on Twitter @QuickResponseFS.

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