Firefighting foam is a collection of bubbles formed by the aeration of a solution of foam concentrate with water.
Foam is made up of three components - foam concentrate, water and air. The finished
Product, foam, floats on a fuel surface to extinguish a flammable liquid fire by separating the fuel from oxygen.
Because of its high water content it also helps cool the fuel surface and any hot objects in the fire area.
There are two basic stages in the generation of foam:
The first is when ”foam concentrate” is added to water in a given concentration to form ”foam solution”. This stage is called proportioning. It is a very critical stage because it is vital that the correct percentage concentration is formed if the foam is to perform properly.
The next stage is when air is mixed with the solution to produce bubbles of foam or ”finished foam”.
Of course, producing bubbles is not all there is to a foam system. There are many different types of foam concentrate available, many types of proportioners and many different types of foam generating and application equipment. For every flammable liquid fire protection problem there is an optimum combination of equipment, concentrate and application technique.
For more detail please find following datasheet.