Fire Extinguisher

Introduction

Fire is a useful chemical reaction if used in a controlled way. It is a lifesaver for many purposes but can be hazardous if burned in an uncontrolled way. A fire extinguisher is a portable device that is used to control a small or blazing fire. Fire is used for many purposes in our day-to-day life. We can’t think of cooking, illuminating light, and other activities in industries without fire. Sometimes in forests, the dry plants caught fire and spread for miles endangering the lives of animals and birds. To stop all these kinds of fires are cooled down by different fire extinguishers. There are different types of fire extinguishers like water and foam based, carbon dioxide based, dry chemical, wet chemical, water mist, etc.

What is a Fire Extinguisher?

A fire extinguisher is a container filled with dry carbon, water, or chemical used to quench a fire. It is used to extinguish fires that broke out by various means like cooking oil, flammable gases, petroleum, wood, clothes, paints, etc. These are kept in handy places from where they can easily be accessible. There are various classes of fire, they are divided based on the type of material that causes fire.

Class of fire	Sources of fire
Class A	ordinary source of rubber, wood, paper, cloths, and other flammable solids.
Class B	is Caused by Flammable Gases like Methane, Butane, Propane, LPG, CNG, etc.
Class C	is caused by electric appliances like computers, motors, transformers, etc.
Class D	This is caused by metals like Zirconium, sodium, magnesium, potassium, etc.
Class K	This type of fire is broken out by liquids or oil materials like petrol, diesel, kerosene, paints, etc.

Explain the Principle on which a Fire Extinguisher works

There are three types of principles on which a fire extinguisher works, it is known as the fire triangle.

• The first principle is a fire extinguisher the source of fire from where a fire broke out.

• The second is air i.e., the supply of oxygen.

• The third is the material that is burning.

The fire extinguisher works with these three elements of fire to control fire.

• Oxygen

• Heat

• Fuel

What are the Types ?

The fire extinguisher is of different types, as the fire extinguisher works according to the source of the fire. So, to quench the fire apparatus is used accordingly. The extinguisher is basically of two types: stored pressure and cartridge operated. Stored pressure stores chemicals in the same chamber and in cartridge types the gas is stored in a different chamber. The stored chambered is more common.

According to the chemical filled in the extinguisher, there are seven types −

• Water and foam Based − The foam based fire extinguisher is used for fires broken out by materials like electric appliances, coal, paper, textile, wood, etc. water- based extinguisher is used for the fire like metals, wood, kitchen fires, etc.

• Carbon Dioxide Based − This type of extinguisher contains carbon dioxide, which hinders the supply of oxygen and helps cool down fire. This is used for fires caused by electricity.

• Wet Chemical-based Extinguisher − This type of extinguisher is used for the fire caused by oils, fats, and in commercial kitchens. It removes the heat based on the fire triangle principle.

• Dry Powder Fire Extinguisher − A dry powder is filled in an extinguisher; it hinders the supply of oxygen to cool down the heat generated. It is used in fire caused by metals, like sodium, zirconium, etc.

• Clean Agent Fire Extinguisher − It contains a halogenated clean agent i.e., halogen with ozone-depleting hydrocarbons. This type of extinguisher is used to quench the fire caused by flammable gases, electronic equipment, transformers, etc.

• Water Mist Extinguisher − They are used to quench fires caused by wood, paper, as well as electric appliances, i.e., Class C type fires. It contains water mist that takes away the heating element of fire.

• Dry Chemical Fire Extinguisher − It is filled with a dry chemical that interrupts the chemical reaction that is the cause of the fire. It works on the fire triangle principle, which hinders the oxygen supply in heat. It is used for the class A, B, and C types of fires.

Working of Water Fire Extinguisher

Water extinguishers are cheap and are used to quench fires broken out by solids like wood, paper, textile, clothes, etc. It contains only water, so it is safe to use near food, children, and patients.

• Water extinguishers are filled with water and designed in such a way that when the seal is broken it expels the water in force to quench a fire.

• First, the seal is broken, and the safety pin is pulled out.

• Then, the lever of the extinguisher is squeezed.

• By squeezing the lever, it forces a pointed rod within the valve that punctures the cylinder containing high-pressure gas.

• The Gas-filled in the cylinder is released into the cylinder filled with water and forces the water downward.

• Pressured water then came out of the pipe, this pressure triggered water to cool down the fire from 4 to 6 feet away.

Preparation of Soda Acid Fire Extinguisher with diagram and explain How it works?

The Soda acid fire extinguisher is prepared with sodium bicarbonate and dilute sulphuric acid. Let’s check the process of preparation of a Soda acid fire extinguisher.

• First, we need a wash bottle with a nozzle, we fill that bottle with 20 ml of sodium bicarbonate ($\mathrm{NaHCO_{3}}$) solution,

• Then, we suspend an ignition tube by a thread that contains a dilute solution of sulphuric acid($\mathrm{H_{2}SO_{4}}$) in the wash bottle,

• The next step is to close the mouth of the bottle,

• After closing the bottle, we tilt the bottle in such a way that the acid-filled ignition tube reacts with the sodium bicarbonate solution,

• After some time, we notice that there is discharge coming out of the nozzle of the bottle.

• That discharge is the of carbon dioxide 𝐶𝑂2, and other products are sodium sulphates and water.

• When we take the discharge near the fire it quenches the supply of oxygen within the fire and the fire cools down.

• The Carbon dioxide 𝐶𝑂2 released during the reaction work as an extinguisher that hinders the supply of oxygen in fire and hence fire cools down.

$$\mathrm{2NaHCO_{3}\:+\:H_{2}SO_{4}\:\rightarrow\:Na_{2}SO_{4}\:+\:2H_{2}O\:+\:2CO_{2}}$$

Conclusion

In the above tutorial, we have studied the fire extinguisher. A fire extinguisher is a container that contains different types of elements like foam, wet chemical, dry chemical, carbon dioxide, water, water mist, etc. we must choose a correct fire extinguisher when a fire breaks out because a wrong type of extinguisher can ignite the fire more despite cooling it down. The fire is divided into five classes class A, B, C, D, and K. These are divided according to the type of material causing the fire i.e., wood, paper, electric appliance, oil, fat, metals, etc. These types of fires are quenched by different types of fire extinguishers known as Foam, water, chemical, and carbon dioxide-based extinguishers.

FAQs

1. Can we use a Water extinguisher to cool down fires caused by electric appliances?

It is not safe to use a water fire extinguisher for electric appliances as water is a conductor of electricity and can cause harm to the person using that.

2. Which is the best extinguisher for electric appliances?

We can use carbon dioxide extinguishers for electric appliances, the 𝐶𝑂2 hinders the supply of oxygen and reduces the heat.

3. How to Use a Fire extinguisher?

To use an extinguisher you have to first pull the pin of the extinguisher, aim the fire then squeeze the lever of the cylinder, and sweep the house of the cylinder towards the fire until it cools down.

4. What is the Fire Triangle?

The fire triangle is the three main causes of fire i.e. first oxygen supply, the Fuel, and the heat i.e., the material that is ignited. These all are responsible for the ignition of fire, to stop fire we need to hinder these fire triangles.

5. What is the colour of the water Fire Extinguishers?

The colour of the water extinguisher is red and used for quenching the fire evoked by paper, wood, rubber, or textiles.