A Method of Measuring the Concentration of Flammable Gases, Mists and Vapours

Many industrial processes may give r i se to flammable concentrations of mists or hot vapours which cannot be measured using conventional explosimeters. Even with gases, uncertainty as to the chemical composition of the fuel may make it difficult to a ssess the fire and explosion hazard. A new type of instrument is described that measures the concentration of a gas, mis t or vapour in te rms of the stoichiometric fuel concentration, giving a direct indication of flammability which is approximately independent of the chemical composition of the fuel. Details a re given of validation experiments, and the sensitivity and accuracy of the device a re discussed with particular reference to sampling of aerosols and to sampling in oxygen deficient atmospheres.