CSA HGV-2:2014 pdf download.Compressed hydrogen gas vehicle fuel containers
Nonmetallic materials normally in contact with hydrogen shall be determined to be acceptable in hydrogen service. Consideration shall be given to the fact that hydrogen diffuses through these materials more easily than through metals; therefore, the suitability of materials shall be verified.Nonmetallic materials shall 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 shall 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 shall not be significantly affected within the scheduled lifetime of the equipment unless replacement is foreseen; specifically, when selecting materials and manufacturing methods, due account shall 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 the degradation effects of hydrogen on the mechanical performance of a material.
6.3.1 Material properties
Steels shall be aluminum killed and produced to predominantly fine grain practice. Steels shall have a maximum tensile strength of 950 MPa for chrome- molybdenum steel and 880 MPa for carbon-manganese steels. For all other steels, the manufacturer shall demonstrate that exposure to high-pressure hydrogen under the service conditions provided in Clause 4 will not cause any harmful corrosion, deformation, or deterioration of the material. The manufacturer should refer to the material performance data in hydrogen environments that can be found in the Sandia National Laboratory Technical Reference for Hydrogen Compatibility of Materials or ANSI/AIAA G-095, ANSI/CSA CHMC 1,ASME B31.12, and SAE J2579, Appendix B for guidance in the selection of steels. The chemical composition of all steels shall be declared and defined at least by:
a) carbon, manganese, aluminum, and silicon contents in all cases; and
b) nickel, chromium, molybdenum, boron, vanadium, or any other elements that are deliberately added.
6.6 Resins
The material for impregnation may be thermosetting or thermoplastic resin. Examples of suitable matrix materials are epoxy, modified epoxy, polyester and vinylester thermosetting plastics, and polyethylene and polyamide thermoplastic material. Resin system materials shall be tested on a sample test panel,representative of the composite overwrap, in accordance with ASTM D2344. Following a 24-hour water boil, the composite shall have a minimum shear strength of 13.8 MPa (2 000 psi).CSA HGV-2 pdf download.