Hot Weather Explodes Fire Extinguisher
Recently a chemical fire extinguisher in the Sudan, exploded for no apparent reason. It was not being used, but exploded while in situ. The top blew off. Examination failed to show the cause of the explosion, but it is presumed the constant heat of the climate had raised the temperature of the acid bottle till it burst and, releasing its contents into the soda solution, generated a heavy pressure which was maintained and added to, as there was a shut-off cock on the appliance.
As a result of the accident, which badly injured a man, the Government sold off all their chemical extinguishers in the country of the type which operates by generation of CO2 gas. We have made most careful inquiries into the accident, says Fire, London, and can only adduce the reason given for the occurrence. Chemical extinguishers in hot climates should not be fitted with taps, and the acid bottle should be of generous dimensions, with a cubic capacity at least double the volume of acid, whether the bottles are sealed or not. Stoppered acid bottles of lesser proportions will permit the acid to escape should its volume be increased by heat. The result would be the gradual loss of acid until the volume on expansion balanced the cubic capacity of the bottle. But as the acid overflowed from time to time, it would set up a charge of gas which could not escape if a tap were fitted, and even if no tap were fitted the appliance would continually and badly seep and lose in efficiency. With a small stoppered bottle and a tap fitted it is possible for successive overflowings of acid to generate a high pressure of gas, which, combined with increase in volume of the heated soda solution, may so reduce the gas space as to bring about an explosion.