[en] The report describes an experimental study of hydrogen jets burning in air, hydrogen formation by sodium in humid air atmospheres, and the effects of nitrogen, water vapor sodium vapor/aerosol, jet velocity, and jet temperature on ignition of hydrogen jets. The results show that hydrogen jets above 1450⁰F (788⁰C) issuing into an air atmosphere need no ignition source for ignition, a hydrogen jet temperature higher than 500⁰F (260⁰C) and containing more than six grams of sodium per cubic meter of jet gas will auto-ignite in an air atmosphere, the burning efficiency of a hydrogen jet decreases rapidly to zero when the oxygen concentration outside the flame region approaches 10 percent, and hydrogen does not form from a sodium-nitrogen jet issuing into a humid air atmosphere until the ratio O₂/(H₂O + O₂) is less than 0.5