Delhi Anaj Mandi Fire: What is fire and how fire extinguishing works
Fire is a type of chemical reaction that releases energy that is also called an exothermic reaction.
A fire accident in Delhi’s Anaj Mandi on Rani Jhansi Road has killed around 43 people. The fire started in a cramped factory manufacturing school bags, bottles and other materials. Here we will try to understand the science behind fire. What causes fire and what are the methods used to extinguish it.
What is fire?
Fire is a type of chemical reaction that releases energy that is also called an exothermic reaction. Heat, fuel and oxidising agents are the three components required to start a fire. Oxygen is the oxidising agent, the fuel can be anything that burns, and heat is an ignition temperature required to start the fire.
Oxygen is present everywhere; a fire starts every time material is exposed to the minimum amount of heat required to start a fire. It starts a chain reaction that makes the fire continue to burn; once it starts, all it requires is fuel and oxygen. The ash is the remnants that don’t burn.
The flames consist of carbon dioxide, water vapour, oxygen, and nitrogen. The colour of the flames shows the quality of burning of a fuel. Blue flame suggests complete burning, whilst yellow and orange contain particles that are not burning completely.
How is fire extinguished?
One of the key elements responsible for fire needs to be removed, namely, the oxidiser. Oxygen is present in the air, hence it is difficult to remove; however, its effect can be minimised. Other elements like heat and fuel can be decreased or removed respectively.
Ways to reduce fire:
We use fire extinguisher cylinders for small fires. Blankets are also used to reduce the presence of oxygen. The extinguishers contain nitrogen, water, foam, and air. The chain reaction that helps in keeping the fire alive can also be stopped to reduce the fire.
Water is used to decrease the heat component that provides ignition to the fire. Once water is sprinkled on fire, it evaporates and reduces the heat in the fire bringing the heat level below the threshold limit.
Water also reduces the amount of oxygen by diluting with it. Once it turns into water vapour it dilutes the oxygen around a fire. Foam is also used to reduce the amount of oxygen. Removing the fuel is also one of the options.