The maximum experimental safe gaps in an 8 l volume vessel were measured
for a range of flange breadths in a closed vessel, and a vessel fitted with the
flame arresters, with hydrogen/air flammable mixtures. The insertion of the
arrester increased the maximum experimental safe gaps and reduced considerably
the maximum explosion pressures. The reduction in the maximum explosion
pressure makes possible the manufacture of safe electrical equipment for
hydrogen/air flammable mixtures, where the stresses imposed by high rates of
burning make the design of such equipment difficult.