Show FIRE prevention TIPS FIRE extinguishers AND USES i ly by J R no ne s son soll oll for class B fires aach as oils gee geemes ses etc water cannot be 1 used successfully es as it may cause I 1 the be fire to spread for t it if gasoline happens to be spilled 1 and ignited ignite 1 on a floor about all ali that a solid stream wod I 1 do is to sp spread ead fire all over the p ace A foam type extinguisher works very well on such fires as it haa ha blanketing arid and coaling effect on the file three pr chemicals leals are aluminum sull sulphate bicarbonate of soda aej a stab stabilizer i zey whose purpose is to make the ables bubbles smaller and more tc tenacious nai the most common size is I 1 th tha 2 gal on oa producing about 20 i gallons of foam the tha chemicals are arc dissolved in water and in separate chambers inside the extinguisher gu isher when the ex ln guilsher ingui sher is turned ursile down thesa chami cals mix generating about 95 lbs ibs pressure pies sure which expels elpes the foam 1 l through the hose this foam consists i of minute bubbles of carbow carbon dioxide gas entrapped in walls of insoluble alum aluminum num hydrate this forms a strong tough elastic and adhesive foam which forms a blanket of bubb es that will exclude the oxygen which is necessary for combustion ani also aso has i a cooling effect upon the fire I 1 the extinguisher has a range of abbat 35 feet and a durat on of about one minute the foam will cling to vertical as well as horizontal surfaces murfa ses or it will float on the e lightest liquids thus preventing ignition re the foam is harmless to the operator and has a lesser wetting effect than water these extinguishers are not ej effective on alcohol fires and must be protected from freezing other chemicals must not be added to lower the freezing point as they will reduce the effectiveness of I 1 the chemical reaction or change I 1 the nature of the discharge only such charges can call be used as can be purchased from the extinguisher manufacturer |