A COMPARISON OF WATER ADDITIVES FOR MOPPING-UP AFTER FOREST-FIRES

A trial was carried out to compare the effectiveness of six extinguish ants currently used in forest fire mopping up operations by the Wester n Australian Department of Conservation and Land Management. The extin guishants; water alone, water with retardant, foam, retardant plus foa m, wetting agent and retardant plus wetting agent were compared by app lying them to burning heaps of dry pine logs. There were twelve replic ates of each extinguishant treatment, with one of each type being appl ied each day over twelve days. Foam, used alone or with retardant, was most effective in extinguishing flaming combustion, both in terms of the time taken and the amount of water used, but was least effective i n preventing the re-ignition of hot, smouldering logs. Retardant plus foam required significantly less total water than the other extinguish ants because of the effect of the retardant in delaying re-ignition. I n terms of total water used the most expensive treatment was straight water, requiring 17% more than retardant plus foam but only about 7% m ore than the other four treatments. The poor performance of the foam t reatments in preventing re-ignitions, may have been due to the method of application. The observed advantage of foam in terms of knockdown c apability needs further validation.