Foam is a suppressant (which is similar to dish soap ) that is applied to fires to suppress or extinguish them.
Fire control foam is created by mechanically aerating a water-diluted concentrate, injecting the concentrate into ground or air-borne water tanks, or by simply dropping the mixture from an air tanker or helicopter.
Once dispersed on a fire, foams absorb heat from combustion while the bubble structure slowly releases water, which is absorbed by wood fuels.
A mixture can produce dry or wet foams, depending on the ratio of water and concentrate. Dry foams produce smaller high-insulation bubbles while wet foams develop larger bubbles that provide better water penetration.
However, wet foams are generally considered more effective fire suppressants because dry foams are difficult to apply effectively, often becoming caught in wind currents or tree branches.
Although fire-control foams are a better suppressant than water, their usefulness is limited, particularly against high-intensity fires, where long-term retardants have proven more successful.
Foam concentrates were not widely used in the province until the 1985 fire season - considered to be one of the worst in Forest Service history. At that time, more than 10 million litres of foam were used to help control and suppress wildfires.
