The ASME B31.12 standard provides a list of materials (Annex 6.1) for hydrogen-compatible piping. When using materials not listed for hydrogen service, tests must be conducted to ensure compliance with ASME B31.12 requirements, including mechanical proper

The ASME B31.12 standard includes a list of materials in Annex 6.1 that are suitable for hydrogen piping. If you want to use materials not on this list, you must conduct tests to ensure they meet the standard's requirements, including checks on mechanical properties, the pipe manufacturing process, heat treatment, and quality control. However, some European steel grades (EN) that are not listed in ASME B31.12 might not need extra testing because they already have good mechanical properties. It's important to note that ASME B31.12 does not take into account the effects of moisture or hydrogen sulfide (H2S) in the gas.