Types of fire extinguishers Uses and Technique

In the 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 important to have proper fire fighting equipment, and the use of a suitable type of extinguisher and technique to use that equipment is equally important. Today, in this post, we are going to learn what is a fire extinguisher in brief, what the types of fire extinguishers and what 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 getting into the fire extinguisher in detail, just have a quick refreshment to what is fire triangle as this is important to know for fire fighting.

What are fire extinguisher?

Fire extinguishers are the equipment designed to control small fire occurred. This is a fire protection device that can be used to fight against fire. There are several types of fire extinguishers which can be used 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 etc but not any fire extinguisher type can be used in all types of fire. There are different types of fire extinguishers available that are used based on the class of fire that occurred. So before getting into fire extinguisher types, let us learn different classes of fire.

The fire occurred when the fire triangle is completed i.e. Fuel, oxygen, and spark. Classes of fire depend on the fuel type in which the 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 categorise 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 include Class E. Let us learn classes of fire in detail and fire in which substance calls 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, and deep-fat fryers.

This categorization of fire in classes helps to understand the material in which fire had caught and based on this fire extinguishers 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 type of extinguisher and it can be used to extinguish class A type of fire. Water fire extinguishers work by having a cooling effect on the fuel, which will remove the heating element that is keeping the fire from burning continuously. This decreases the fire intensity and ultimately fire is extinguished. This extinguisher can be used in fires caused by wood, coal, paper, and fabrics.

What is the Water Fire Extinguisher Label Colour?

The water extinguisher 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 compared 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 seals the surface and makes the fire starved of fuel and breaks fire triangle by eliminating fuel from the triangle and extinguishing the fire. It can be used on fire of wood, paper, textile, and plastic and is most suitable on petrol and diesel.

What is the Water Fire Extinguisher Label Colour?

The water extinguisher’s label colour is Cream.

3. Dry Powder (DCP)

Dry chemicals powder or dry powder extinguishers are also known as ‘ABC’ extinguishers as they can be used to tackle classes A, B, and C. Chemicals like Monoammonium phosphate, Potassium bicarbonate, Sodium bicarbonate, etc are used as a chemicals in DCP. Dry powder removes the heating element from the fire which keeps the fire continuing 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 panels as it makes 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?

The water extinguishers label colour is Blue.

4. Carbon dioxide

CO₂ fire extinguishers as the name suggests, it is filled with non-flammable carbon Dioxide fire extinguishers are designed to be used in electrical fires and fires in flammable liquids such as a solvents. Carbon dioxide extinguishers are also used in class B and class C types of fire. As we use a CO2 fire extinguisher when applied, it displaces oxygen from the fire source and suffocates the fire with CO2 resulting in the breaking of the fire triangle and fire extinguished.

What is the Water Fire Extinguisher Label Colour?

The water extinguisher 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 starving the fire of oxygen. This breaks the fire triangle and helps in extinguishing 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 used to extinguish fire but they are not classified. The details and working of the same are described below.

1. 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 staves the fire of oxygen and helps to stop fire. In case of fire in the electrical panel, electrical transforms, and multiple sand buckets are placed.

2. Fire blankets

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.

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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 a portable fire extinguisher, if one finds that fire intensity is increased, 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 firebase also known as the fuel source till it stops.

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 firefight just by reading the above-written technique steps.

FAQ (types of fire extinguishers and their uses)

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 yourself updated.