Convection:
It is ocures only in liquids and gasses.When liquid or gas is heated it expand & becomes less dense. The lighter fluid raises up and the colder liquids which is denser goes down. Thus a circulation is set up in the fire situation in a building convection currents can convey hot gasses produced by combustion through stairwells and open lift shafts there by spreading fire to the upper part of a building .As the hot gasses rise up , cold which is denser will move down towards fire and accelerate burning.
Radiation:
Heat may all so may transmitted in straight lines by a meanse ,which is neither conduction nor convection. Heat from the sun passes through empty space to warm the earth.Heat from the heater placed at a height level in room can be felt underneath the heater.This method of heat transmission is named as Radiation. It does not involve any contact beetween the bodies and is independent of any material in the intervening space .All forms of radiant energy travel in a straight lines at 3*10^8 ,eter per seconds.Many fire can be caused by radiation . One of the most common fire due to radiation is cloth being ignited by placing to close to a sours of radiation.
It is ocures only in liquids and gasses.When liquid or gas is heated it expand & becomes less dense. The lighter fluid raises up and the colder liquids which is denser goes down. Thus a circulation is set up in the fire situation in a building convection currents can convey hot gasses produced by combustion through stairwells and open lift shafts there by spreading fire to the upper part of a building .As the hot gasses rise up , cold which is denser will move down towards fire and accelerate burning.
Radiation:
Heat may all so may transmitted in straight lines by a meanse ,which is neither conduction nor convection. Heat from the sun passes through empty space to warm the earth.Heat from the heater placed at a height level in room can be felt underneath the heater.This method of heat transmission is named as Radiation. It does not involve any contact beetween the bodies and is independent of any material in the intervening space .All forms of radiant energy travel in a straight lines at 3*10^8 ,eter per seconds.Many fire can be caused by radiation . One of the most common fire due to radiation is cloth being ignited by placing to close to a sours of radiation.
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