1. Ensure that equipment and materials exposed to hydrogen are compatible with a hydrogen environment (even hydrogen-service-rated equipment).
2. Equipment designs in a hydrogen environment that use the fracture toughness for 17-4 precipitation hardening stainless steel may want to consider a 90% derating in published values (see Attachment 1).
Additional discussion of materials selection for compressed gas storage vessels can be found in the Hydrogen Safety Best Practices Manual. Similar discussion of materials selection for cryogenic liquid storage vessels can be found in the Hydrogen Safety Best Practices Manual.
A web-based resource developed by Sandia National Laboratories to provide data on hydrogen embrittlement of various materials is available at Technical Reference for Hydrogen Compatibility of Materials.