CSA ANSI HGV 3.1:2015 pdf download.Fuel system components for compressed hydrogen gas powered vehicles
4.1.2 Material requirements
Resistance to chloride stress corrosion cracking should be taken under consideration if selecting stainless steel materials. Resistance to sustained load cracking should be taken under consideration if selecting aluminum materials. Resistance to galvanic corrosion should be taken under consideration when joining components containing dissimilar materials.
Materials normally in contact with hydrogen should be determined to be acceptable in hydrogen service, with particular attention to hydrogen embrittlement and hydrogen accelerated fatigue.Materials and design should be such that there will be no significant change in the functioning of the device, deformation or mechanical change in the device, and no harmful corrosion, deformation, or deterioration of the materials.
Note: Information regarding material performance in hydrogen environments may be found in the Sandia National Laboratory Technical Reference for Hydrogen Compatibility of Materials, ANSI/AIAA G-095, CSA CHMC1, and ASME B31.12.
Non-metallic materials normally in contact with hydrogen should be determined to be acceptable in hydrogen service. Consideration should be given to the fact that hydrogen diffuses through these materials more easily than through metals; therefore, the suitability of materials shall be verified.Non-metallic materials should retain their mechanical stability with respect to strength (fatigue properties, endurance limit, creep strength) when exposed to the full range of service conditions and lifetime as specified by the manufacturer. Materials should be sufficiently resistant to the chemical and physical action of the fluids that they contain and to environmental degradation; the chemical and physical properties necessary for operational safety should not be significantly affected within the scheduled lifetime of the equipment unless replacement is foreseen; specifically, when selecting materials and manufacturing methods, due account should be taken of the material's corrosion and wear resistance, electrical conductivity, impact strength, aging resistance, the effects of temperature variations, the effects arising when materials are put together (for example, galvanic corrosion), the effects of ultraviolet radiation, and to the degradation effects of hydrogen on the mechanical performance of a material.
The manufacturer shall provide documentation acceptable to the independent inspection or test agency verifying the material's suitability including consideration for such characteristics as permeability, creep,long term aging, stress cracking, and retention of mechanical properties, as appropriate. Safety margin shall be demonstrated by the hydrostatic strength test, allowable leakage, and the use of materials below their creep threshold for their qualification temperature.CSA ANSI HGV 3.1 pdf download.