The Parts of a Fire Extinguisher Explained

Whether it’s water, foam, dry chemical, or clean agent fire extinguisher, you can find these safety items everywhere. In case of an emergency, it is important that you know how to use one. The parts of a fire extinguisher play a critical role in its function.

This article will talk about fire extinguisher parts and how each part is significant to the overall mechanism.

What Are the Parts of a Fire Extinguisher?

The most basic components in a fire extinguisher would be the cylindrical tank which contains the propellant and the chemical agent used to put out the fire, a valve or lever to release the agent, a pull pin, and a hose to direct the extinguishing agent.

However, there are more fire extinguisher parts that contribute to the storing, expelling, or informing of the chemical agent and propellant. We’ll talk about each one in detail.

Fire Extinguisher Body or Barrel

The main body or barrel of the fire extinguisher is also known as the cylindrical tank. It contains the propellant and the extinguishing agent, storing it at the correct pressure. 

They are mostly made of steel which makes them heavy even if they are smaller in size. Some manufacturers treat the cylinder with a galvanizing compound undercoat, protective topcoat, and clear coat finish to reduce the effects of corrosion and exposure to the sun.

Parts Of A Fire Extinguisher

Fire Extinguisher Nozzle

The discharge nozzle is at the end of the fire extinguisher’s hose and is responsible for expelling the extinguishing agent. Its conical shape allows you to easily disperse the water, foam, chemical, or any other agent in the appropriate direction of the fire. 

Only fire extinguishers that weigh more than 3 kilograms have a hose. This flexible pipe allows you to direct the nozzle where you want.

Fire Extinguisher Decal

A decal is a sticker label or sign put up on walls, windows, floors, or vehicles. Hazard Communication Standards (HCS) requires all employers to post OSHA and NFPA 10 compliant Fire Extinguisher Decals.

These are meant to indicate a fire extinguisher’s location on the premises so that personnel and emergency responders can easily find them during an emergency.

Some companies manufacture “glow in the dark” fire extinguisher decals, which can help people locate them if the power goes out.

Fire Extinguisher Gauge

When it comes to fire extinguisher parts, the pressure gauge is one of the most important ones. It lets you see the pressure inside the tank, which will indicate whether it has been damaged or already used. The recharge zone, green zone, and the overcharged zones will help you determine whether the fire extinguisher is leaking, is good to go, or if it needs servicing.

Fire Extinguisher Label

Fire extinguishers come in different types according to the class of fire they can be used on. Labels are critical parts of a fire extinguisher used in identifying which fire extinguisher can be used when. Occupational Safety and Health Administration (OSHA) requires all hazardous chemicals and materials to be labeled properly.

Here is how the fire extinguisher should be labeled according to its type:

  • Water Fire Extinguisher

This label should be in white writing on a red tank. It is used to put out class A fires involving paper, plastics, or wood. Water mist cans have a similar label, with the difference being that they can be used for class B, C, E, and F fires as well.

These labels are cream in color and can be used on class A and class B fires involving liquids or solids.

  • Powder Fire Extinguishers:

Dry powder tanks are red with a blue label. It is primarily used for class B, C, and E fires, but I also useful in putting out class A fires. When in doubt, remember that blue is for electrical equipment.

  • Carbon Dioxide Fire Extinguishers:

Like the others, these fire extinguishers have a red tank but have a black label. Another marker to identify this type of extinguisher is through the large cone-shaped nozzle. They are most effective for class E fires but can occasionally help put out small class B fires.

  • Wet Chemical Fire Extinguishers:

Wet chemical labels are yellow on a red tank. They were designed specifically for class F fires since they can make chemical changes to burning oils. 

Fire Extinguisher Inspection Tag

One of the most important fire extinguisher parts is the inspection tags. They outline a list of inspections, the dates they were completed, and a description of the extinguisher’s type and model.

According to NFPA 10 standards, inspections must be carried out in four categories, monthly, yearly maintenance, and 6-year and periodic hydrostatic materials checkups. Each inspection must be recorded on the inspection tag.

Fire Extinguisher Pin

The pin in a fire extinguisher prevents the lever from being accidentally pressed. It is usually sealed to indicate that it has not been used or tampered with. Removing the pin, either by pulling it out or twisting it to 90 degrees, will allow you to discharge the contents by squeezing the lever. The pin can be re-inserted into the activation handle to prevent it from being depressed. 

Fire Extinguisher Quick Release

In an emergency, it is easy to get flustered. That is why these quick releases are designed to make it convenient to take out the fire extinguisher for use. Quick-release knobs or clips are found on fire extinguisher mounts, brackets, and straps to allow for fast access to the tank.

Fire Extinguisher Quick Release Mount

A quick-release fire extinguisher mount allows it to be easily and quickly pulled out and used with a pull of the handle. Many models allow you to release the container with one hand while preventing accidental release.

Fire Extinguisher Quick Release Strap

Straps are necessary parts of a fire extinguisher to anchor the tank to the wall or cabinet. It must also be resistant to damage or movement in the event of an earthquake. A fire extinguisher can contain hazardous chemicals, so the straps must be secure enough to hold it in place. 

The straps are typically made of stainless steel, fastening to transportation brackets. Many contain a quick-release clip for fast access. 

Fire Extinguisher Key

Since many fire extinguishers are kept in a locked cabinet, they require a key to open them. A key box can help you keep track of the key. Alternatively, you could have a key and lock set installed into the cupboard to prevent unauthorized use.

Parts Inside of a Fire Extinguisher

The tank contains the extinguishing agent and propellant gas. According to the type of fire extinguisher, the inside can contain water, foam, liquid and gaseous carbon dioxide, or dry powder with compressed nitrogen. 

A siphon tube runs through the barrel, which allows the liquid or agent to expel out of the hose when pressure is built up. Less commonly used cartridge-operated extinguishers have a separate cartridge for the expellant gas. This needs to be punctured to expose the propellant to the extinguishing agent.

In Summary

In conclusion, there is more to fire extinguisher parts than just the tank, valve, and hose. The decals, labels, and quick releases are just as necessary to ensure the safety protocols that come with fire extinguishers. Moreover, having a working knowledge of the different parts of a fire extinguisher helps you troubleshoot any issues you might face if you ever need to use one.

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Nick Klamecki, Author
About Nick Klamecki, Author

Nick Klamecki is a certified Fire and Workplace Safety expert with 15 years experience in product research and testing. He has a degree from U.C. Davis, is an active outdoorsman and spent years ensuring the safety of special needs children. Nick researches and tests workplace, industrial and safety products and provides advice on their safe use. Learn more about Nick here or connect with him on LinkedIn | Medium