| MadSci Network: Chemistry |
Fire is a chemical chain reaction involving the oxidation of a fuel ( what is burning ) being reduced by the heat ( the flame ) producing fire gases, ashes ( what is left of the material oxidized ), heat and light. In order to stop this reaction the fire must be acted upon in one of four ways:
1. You may exclude the oxygen.
2. You may remove the fuel ( what is burning. )
3. You may cool the fire using water or some other agent to the point
where the self sustaining thermal balance is interrupted and less heat is
given off than is taken in: or
4. You may stop the chemical chain reaction by using an agent made just
for such a purpose such as any one of a few varieties of halon gas. Halon
interferes with the chain reaction to the point where the fire can no
longer burn. Halon is used on board air planes in the engine compartments
and in sensitive computer rooms where water is terribly damaging to very
sensive equipment. It is in limited use today due to the fact that its
introduction into the atmosphere has been shown to damage the Ozone Layer
of the Earth's outer atmosphere.
For more information on fire go to the International Fire Service Training Association's website or the National Fire Protection Agency's website.
Thank you for the question, Sally. Keep in mind that when one uses water to extinguish fire it is in essencce acting on the fire in two ways:
1.)
It is cooling the fire below its fire point and;
2.) It also has a
suffocating effect by excluding the oxygen.
Try the links in the MadSci Library for more information on Chemistry.