How can we Extinguish Fire?
How does a Fire Extinguisher works
A fire is basically a chemical reaction during which heat and light are produced. Three factors are necessary for a fire to start – Fuel oxygen or air and heat to raise the temperature of the fuel to its ignition temperature. A fire can be Extinguished when one or more of these agents is removed ie. fuel supply of air and lowering the temperature of the combustible substance. The original fire Extinguisher a bucket of water is still useful in controlling many types of fires. The principal effect of water on a fire is to cool the burning material, thus removing the heat. Another common Extinguisher is to sprays a mixture of water and carbon dioxide on the fire. This is based upon the principle of cooling the burning material and cutting the supply of air by non-combustible carbon dioxide.
In this Extinguisher a solution of sodium bicarbonate is placed in a cylindrical vessel of steel. Sulphuric acid is kept in a bottle in a small compartment made within the cyclinder near the top. When required the knob is hit against the floor. This brings the sodium bicarbonate and sulphuric acid in contact with each other. Immediately carbon dioxide is formed and it comes out of the fire nozzle which is directed towards the fire. Water should never be used for Extinguishing electrical or iol fires. In case of electrical fires, it can cause electrocution. If water is used on burning oil the simply floats on top of water and continues to burn. As the water flows away, It can carry the oil with it and so spread the fire.