The
Fire Triangle
This
is the basis of fire and fire fighting. In order
to understand how extinguishers work, it is important
that you have some insight on fire.
Basically, three elements must be present at the same time, in the right proportions
to produce fire:
1. Oxygen to
sustain combustion. Ever present in the atmosphere.
2. Heat to raise the material
to its ignition temperature. Present in many areas
from light bulbs to welding sparks.
3. Fuel or combustible material. Used and stored at home,
school or work. Paper, books, chemicals, gasoline.
The
chemical, exothermic reaction that is fire is usually
classed as a fourth element that keeps the fire
burning.
If
one leg of the triangle is missing, there would
be no fire. The objective of fire protection
therefore is to ensure that the fire triangle is
never formed. Since there is nothing we can do about
the presence of oxygen in the atmosphere, combustible
or material fuels sources and heat or ignition sources
should be kept apart all the times.
Fire
extinguishers put out fire by taking away one or more
elements of this fire triangle.
There is: -
Starving, this refers to the removal of the fuel so that the fire
is starved. This is the Fuel leg of the triangle.
Smothering which refers to the displacement of oxygen through the
use of Foam, Dry Chemicals or Carbon Dioxide or other inert gases. This is
the Oxygen leg of the triangle.
Cooling which refers to the elimination of the heat leg of the triangle
through the use of water.
