A series of experiments on the formation of roof layers of buoyant
flammable gas, using mixtures of natural gas and air and also 100 per cent
natural gas, is described in which both vertical and horizontal distributions of gas concentration were determined.
Mixing of the introduced flammable gas with air in the explosion
chamber has reduced by the adoption of appropriate input conditions. The
distribution of gas in horizontal planes in all mixtures was found to be
uniform but the vertical distribution of gas indicated the formation of
diffuse layers, particularly when introducing 100 per cent natural gas. The
effects of filling rate and also the charge of concentration with time in a
quiescent layer are described.