The indisputable need by heat treaters to save energy, boost productivity, minimize distortion and improve metallurgical properties while reducing environmental impacts should lead furnace manufacturers to place an increased emphasis on enhancing gas quenching performance. The purpose of this study is to analyze the cooling performances of the various quench gases that are available to the vacuum heat treater. The benchmark gas for quenching, and the industry standard for many years has been nitrogen. Based on theoretical thermodynamics of gases, the hypothesis states that hydrogen should cool 50%2faster than nitrogen and hydrogen should cool 17%2faster than helium. [GRAPHICS] With the ever-increasing expense of helium and the world's reserves of helium being finite, Solar Atmospheres' engineers are working to understand high pressure cooling properties of hydrogen. Safety issues, of course, must be resolved when working with hydrogen. Solar engineers are working on this subject everyday while being guided by NFPA 86 Code.