Ignition of combustible dusts on hot surfaces

The minimum temperatures for ignition of beech sawdust layers on a hot surface have been determined for a range of depths, densities and particle sizes of the dust. Some other dusts of vegetable origin have also been studied, though less extensively. The results have been correlated by an extension of known thermal ignition theory which permits the prediction of conditions for ignition outside the range of experiment. A comparison of results on the ignition of a material on a hot surface, and at a uniform ambient temperature in an oven, provides a limited check on the validity of assumptions made in this application of the theory.