Hydrogen is the most abundant element in universe and according to many predictions it will be the future fuel of human being so recognizing its nature as well as its hazards will be of a tie for entering to the hydrogen era. Proceeding to the safety of it is one of the main challenges that is allocated a novel branch of science to itself. In this paper, the authors studied the physical and chemical properties of hydrogen from safety view of point. Therewith the other characters of this fluid like: leak rate, safety gap, flammability limit, ignition energy, explosion limit and cell width were discussed. Since there is no safe material from hydrogen corrosion attack then the material structure for hydrogen flow rate was discussed comprehensively in this paper.