Flammability of methane, propane, and hydrogen gases

This paper reports the results of flammability studies for methane, propane , hydrogen, and deuterium gases in air conducted by the Pittsburgh Research Laboratory. Knowledge of the explosion hazards of these gases is important to the coal mining industry and to other industries that produce or use fl ammable gases. The experimental research was conducted in 20 L and 120 L cl osed explosion chambers under both quiescent and turbulent conditions, usin g both electric spark and pyrotechnic ignition sources. The data reported h ere generally confirm the data of previous investigators, but they are more comprehensive than those reported previously. The results ii lustrate the complications associated with buoyancy, turbulence, selective diffusion, an d ignitor strength versus chamber size. Although the lower flammable limits (LFLs) are well defined for methane (CH4) and propane (C3H8), the LFLs for hydrogen (H-2) and its heavier isotope deuterium (D-2) are much more depen dent on the limit criterion chosen. A similar behavior is observed for the upper flammable limit of propane. The data presented include lower and uppe r flammable limits, maximum pressures, and maximum rates of pressure rise. The rates of pressure rise, even when normalized by the cube root of the ch amber volume (V-1/3), shown to be sensitive to chamber size. Published by E lsevier Science Ltd.