Improvements in foaming compounds for fire fighting

742,101. Foam compositions. PYRENE CO., Ltd. Feb. 15, 1951 [Nov. 16, 1949], No. 29276/49. Class 47 Mechanical or chemical fire-fighting foam for application to a burning watermiscible organic liquid is prepared by a method comprising incorporating a watersoluble alginate in the liquid stream used to form mechanical foam or in one of the reacting liquids or the dry powder used to form chemical foam before the foam is produced, the amount of alginate being such as to make the foam substantially impervious to the burning liquid. The foam also contains one of the usual foam-stabilizing agents such as "Aptersol" (Registered Trade Mark) or, preferably, partially hydrolyzed proteins in the case of mechanicalfoams and saponine, turkey red oil or liquorice in the case of chemical foams. Sodium alginate is the preferred alginate, rather than the ammonium salt. Examples are given of concentrates using hydrolyzed-blood type stabilizing agents. Chemical foams may be formed from aluminium sulphate solution and sodium bicarbonate solution containing alginate. In an example, the alkaline solution is prepared by mixing alginic acid, excess sodium bicarbonate, liquorice and sodium benzoate, and the acid solution by mixing aluminate sulphate and citric acid with water. A suitable dry powder suitable for making the chemical foam comprises alginic acid, excess sodium bicarbonate, aluminium sulphate and liquorice.