Types of fire extinguishers Uses and Technique

Types of fire extinguishers

In a chemical Industry, fire accidents are very common. Fire hazards fall under physical hazards which is one of the 6 Types of Hazards at Workplace. Industries must focus on workplace safety. When it comes to workplace safety, fire safety comes first. To tackle fire safety, fire extinguishers are used. There are various types of fire extinguishers available and the application of those are based on the class of fire.

In case of fire, it is not only important to have proper fire fighting equipment, but use of a suitable type of extinguisher and technique to use that equipment are equally important. Today, in this post, we are going to learn what is a fire extinguisher in brief, what are the types of fire extinguisher and classes of fire.

There are various stages of fire and we had discussed in detail. This basic knowledge of the stages of fire will help us in fire fighting. Quick action is required while fire fighting but having a knowledge of the workplace where the fire has occurred and types of substance in which fire had occurred i.e. substance acting as a fuel for the fire, types of material present near the fire area also need to be considered. Prior to get into the fire extinguisher in deatail, just have a quick refreshment to what is fire triangle as this is important to known for fire fighting.

What are fire extinguisher?

Fire extinguisher are the equipment desigen to control small fire occured. This is a fire protection device that can be use to fight against fire. There are several types of fire extinguisher which can be use for different types of fire.

Fire extinguisher classes

Now you know that fire extinguishers are necessary for any chemical industry, and not only that, commercial buildings, apartments, houses, hospitals, schools malls and etc but not any fire extinguisher type can be used in all type of fire. There are different types of fire extinguishers available that are used based on the class of fire that occurred. So prior to getting into fire extinguisher types, let us learn different classes of fire.

The fire occurred which the fire triangle is completed i.e. Fuel, oxygen, and spark. Classes of fire depending on the fuel type in which fire has occurred. The main purpose of the fire extinguishers is to break the fire triangle by eliminating anyone fire triangle element to stop the fire.

Classes of fire

Classes of fire is a system to categorized fire based on the substance acting as fuel for the fire. Broadly there are 5 major classes of fire i.e. from Class A to F (excluding E), but some countries also included Class E. Let us learn classes of fire in details and fire in which substance call in which particular class

  1. Class A – fires on solid materials such as trash, paper, wood, wool, or textiles.
  2. Class B – fires on flammable liquids such as petrol, diesel or oils.
  3. Class C – fires in gases.
  4. Class D – fires in metals.
  5. Class E – fires in live electrical apparatus. (In most countries, class E i.e. electrical fire are unclassified but in Asian countries, these are classified as Class E)
  6. Class F – fires in cooking oils such as in chip pan-fries, deep-fat fryers.

This categorization of fire in classes help to understande material in which fire had caught and based on these fire extinguisher are assigned.

Five types of fire extinguishers

  1. Water, water mist, or water spray
  2. Foam
  3. Dry Powder – standard or specialist
  4. Carbon Dioxide (CO2)
  5. Wet Chemical

1. Water | Water Mist | Water spray

Water is the basic and most commonly used types of extinguisher and it can be used to extinguish class A type of fire. Water fire extinguishers work is by having a cooling effect on the fuel, which will remove the heating element that is keeping the fire to burn continuously. This decrease the fire intensity and ultimately fire is extinguished. This extiguisher can by use in fire cause by wood, coal, paper, and fabrics.

What is the Water Fire Extinguisher Label Colour?

Water extinguishers label colour is bright red.

Note – Don’t use water to tackle fire in solvent as some solvent are lighter than water i.e. density of solvents are less compare to water so, if you spray water on the solvent fire, the solvent will float over water and will spread along with fire result in an increase in fire.

2. Foam | AFFF

Foam type of extinguisher also known as AFFF. AFFF stands for Aqueous film forming foam is also very effective in fire of class A and B fire. AFFF /Foam works in two ways, firstly it provides a cooling effect to the fire to slow down the fire and other is it sealed the surface and make the fire starved of fuel and break fire triangle by eliminating fuel from the triangle and extinguish the fire. It can be use on fire of woods, paper, textile, plastic and are most suitable on petrol and diesel.

What is the Water Fire Extinguisher Label Colour?

Water extinguishers label color is Cream.

3. Dry Powder (DCP)

Dry chemicals powder or dry powder extinguishers are also known as ‘ABCextinguishers as they can be used to tackle class A, B, and C. Chemicals like Monoammonium phosphate, Potassium bicarbonate, Sodium bicarbonate, etc are used as a chemical in DCP. Dry powder removes the heating element from the fire which keeps the fire continue or it also removes oxygen from the fire and breaks the fire triangle to extinguish the fire. On the use of DCP, residue remains so it is recommended not to use on electrical and instrumentation panel as it make it faulty. Also, these are not recommended for use in enclosed spaces as the powder can be easily inhaled and can cause breathing problems.

What is the Water Fire Extinguisher Label Colour?

Water extinguishers label colour is Blue.

4. Carbon dioxide

CO2 fire extinguisher as name suggest, it is filled with non-flammableCarbon Dioxide fire extinguisher are designed to by use in electrical fires and fire in flammable liquids such as a solvent. Carbon dioxide extinguisher are also use in class B and class C type of fire. As we use CO2 fire extinguisher when applied, it displace oxygen from the fire source and suffocates fire with CO2 results in breaking of fire triangle and fire extinguished.

What is the Water Fire Extinguisher Label Colour?

Water extinguishers label colour is Black.

Note – Avoid touching hard horn of extinguisher and also direct skin contact with dispersed CO2 as it is extremely cold and you can have frostbite.

5. Wet Chemical

Wet Chemical fire extinguishers are used on fires involving combustible cooking media such as burning oil and fat. Wet chemicals form a layer over the burning oil and fat and results in starves the fire of oxygen. This breaks the fire triangle and helps in extinguish the fire.

They have a class F rating and a special lance applicator nozzle. They usually have an additional class A rating and are normally not designed for use on class B fires (petrol, diesel, paint, paraffin etc), although the 3ltr Gloria wet chemical fire extinguisher is an exception.

What is the Water Fire Extinguisher Label Colour?

Water extinguishers label colour is Yellow.

Unclassified fire extinguisher

Apart from the main fire extinguishers type, sand, fire blankets are also use to extinguish fire but they are not classified. The details and working of the same are described below.

Fire Bucket

fire bucket

A fire bucket is a bucket filled with sand. These buckets filled with sand can be used in case of a small fire and can act at the incipient (initial) stage of fire. This method is very old but still can be effective in some cases. Sand buckets are dumped on the fire source which staved the fire of oxygen and helps to stop fire . In case of fire in the electrical panel, electrical transforms, multiple sand buckets are placed.

Fire blankets

use of fire blanket

Fire blankets are the blanket-made material that can withstand high temperatures up to 800 °C. In case of a small fire at home, kitchen in LPG cylinder, fire in hairs while cooking, fire in clothes at home, on can cover the fire with fire blanket which will cut off the oxygen to the fire and a small fire can be stopped.

Which fire extinguisher types to use

  1. Class A – water, DCP, AFFF foam, Water mist, wet chemical
  2. Class B – water mist, foam, dry powder, CO2, some wet chemical
  3. Class C – water mist, dry powder
  4. Class D – specialist dry powder
  5. Class E– CO2, DCP
  6. Class F – water mist, wet chemical.

Technique to use Fire extinguisher

There is a technique to use fire extinguishers and this is to be learned by all the employees of the workplace. Proper use of fire extinguisher will help you to control fire at the very initial stage. It is important to note that fire fighting is important but not every fire can be put off using portable fire extinguisher, if one find that fire intensity is increase, it is recommended to inform to fire station.

The following four-step technique can be memorized more easily with the acronym PASS:

  1. Pull: Pull the pin to break the tamper seal.
  2. Aim: Aim low, pointing the nozzle or hose at the base of the fire.
  3. Squeeze: Squeeze the handle to release the extinguishing agent.
  4. Sweep: Sweep from side to side at the fire base also known as fuel source till it stopped.

Note – Written step to use fire extinguishers is required by practical use should be the priority. It is recommended to take fire fighting training including training to use fire extinguisher. Don’t rush to fire fight just by reading the above-written technique steps.

FAQ (types of fire extinguisher and their uses)

1. Can you use fire extinguisher on electrical fire?

ABC type of fire extinguisher and CO2-based fire extinguisher can be used in an electrical fire.

2. Why is the fire extinguisher pin sealed?

Pin sealed of fire extinguisher is a proof the fire extinguisher is new and not a used one. Also this pin sealed ensure unnecessary discharge that can be done by accidently pressing of handle

3. Where is the expiry date on a fire extinguisher?

Yes, fire extinguisher had a expiry date and one can find it on the cylinder of the Fire extinguisher.

Wrapping Up

This is the detailed information of different types of fire extinguishers and a detailed guide on how to select the correct fire extinguisher based on fire classes. In the meantime, you can read industrial safety-related articles like NFPA Diamond Diagram. If you have any doubt regarding this topic then feel free to use the comment section. Don’t forget to check  Steps Of Hazard Prevention where we had discussed methods to prevent hazards in the chemical industry. Download our official app to keep your self updated.

Avatar of Ronak Prajapati

Me - Founder of Chemical Tweak - A Chemical Engineer by profession and a part-time self-trained technology blogger.

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