Fire Safety Science Digital Archive

The proportions of barium sulphate and magnesium oxide dusts required to prevent explosions, in phenol formaldehyde resin and polyethylene dusts dispersed in air in a large scale vertical tube have been determined. The behaviour of the dust mixtures in the routine small scale Classification tests has also been studied. In further experiments with small scale apparatus, the explosibility of mixtures of phenol formaldehyde resin with other diluents has been observed. The results have been used to test further a theory developed previously for determining the percentage of diluent required to prevent explosion when dispersed with the combustible dust.. The theory was based on a heat balance in which the function of the diluent dust was to act solely as a heat sink. The theory was in good agreement with the results obtained with the large scale apparatus, and with most of the results from the small scale apparatus. A diluent which was markedly more effective than predicted was sodium iodide.