Although hydrogen is expected as clean energy it potentially has an explosion hazardous nature due to a wide range of explosion limit and a small value of minimum ignition energy. In this paper ignition, combustion, explosion and detonation characteristics of hydrogen-air and hydrogen-oxygen mixtures are presented with their data such as ignition temperature, explosion limit, minimum ignition energy, detonation parameters etc.. Based on these data safety evaluation procedures are described from the point of view of prevention, protection and mitigation of accidental explosions.
