Hello Readers. It has been some days now since my last blog. Have been a bit busy with official duty and training programmes and hence the delay in posting the blog. Shall take care to increase the frequency of my blogs so that the readers are not kept waiting. In my last blog we had discussed the ways and means of fire fighting via Starvation, Blanketing and Cooling. In this we shall discuss the methods of the spread of fire.

Fire fighting is quite easy if fire is just confined in a small area. However most of the times, it is not. Very quickly it spreads to other areas by the transfer of heat. Transfer of heat happens due to Conduction, Convection and Radiation. Let us discuss in detail the same.

CONDUCTION : In this method of heat transfer, the transfer of heat happens through solid particles between two or more objects. Speed of the transfer varies from one material to other. Iron, Steel and other metals have good heat conduction whereas wood has low heat conduction. This way of heat transfer was demonstrated by our teachers in the science laboratory by holding a metal rod over a Candle. In the same way fire also moves from one place to the other using Solid materials while burning.

CONVECTION : Convection is the transfer of heat energy by the movement of heated liquids or gases, from the source of heat to a cooler part of the environment. In fire spread this happens through the heated smoke travelling upwards. This method of heat transfer is very dangerous as smoke can enter in buildings in many ways like shafts, air conditioner ducts, open doors and windows and even through holes in walls. Hence as per the NBC (NATIONAL BUILDING CODE) states that high rise buildings should provide pressurised staircases to avoid spread of smoke and for easier evacuation. Convection in buildings can be prevented by closing of doors and windows whenever smoke is present.

RADIATION : Radiation is the transfer of heat Energy from a hot surface to a Cooler surface through electromagnetic waves without an intervening medium. In this method the spread of fire is through the air and hence if the fuel load is high in a particular area the fire can spread rapidly. The best example to understand radiation is the heat from the Sun. Radiation can be prevented by cooling the surrounding areas of a fire with water.

Fires can sometimes ignite and spread through a method called direct burning like lightning strikes or even because of the wind direction.

By reading the above one can easily understand how fire spreads and how one can save oneself during fire accidents. We shall discuss more in the next blog. Stay Safe and Be Safe

Seshadri Varadarajan
Mobile 9840814353
Email seshadri3225@gmail.com
You tube channel LIVE AND LET LIVE.

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