The scientific name for burning is "combustion." In most cases oxygen from the air combines with some material that can burn. This produces heat. If the process takes place rapidly, we may see flames or an intense glow which is called fire.
Chemically during combustion, two atoms of oxygen from the air combine with one atom of carbon from the fuel to form carbon dioxide.
How Fires Get Extinguished?
An understanding of how fires burn is essential if a fire is to be extinguished. The three (3) major elements of fire are: a) air; b) heat; and, c) fuel. All three of these elements inter-react to create a fire. If the reaction linking the elements is interrupted, the fire will be extinguished.
The simplest method of extinguishing a fire is by pressurized water hose. This is a pressurized-water extinguisher and works by removing heat. The fire's heat goes into heating and evaporating the water, which has a very high heat capacity, and soaking the burning materials with enough water will cool them to below the combustion point.
There are other fire extinguishers which work on chemical reaction. We give below the description of such types of fire extinguishers.
1. The high-pressure CO2 extinguisher removes oxygen and, to a certain extent, heat. The expanding CO2 cools, sometimes enough to produce dry ice snow, but the main effect is to blanket the burning material with a heavy gas that cannot support combustion. CO2 extinguishers leave no residue. CO2 extinguished materials usually retain enough heat to re-ignite when the CO2 dissipates. CO2 extinguishers are normally red and have large nozzles. These are used mostly for fire caused by burning of Electrical fires.
2. Halon extinguishers normally contain bromochlorodifluoromethane, a very heavy gas (much heavier than CO2). This not only displaces oxygen from...