Instruments (thermocouples, flow controllers, etc.) should be tested and recalibrated or replaced on a regular basis.
Use of a positive material verification program is recommended for equipment in hydrogen service. Verification of metal alloys using x-ray fluorescence, or non-destructive material testing, is accurate, inexpensive, and fast. The verification program should require testing per API Recommended Practice 578, or another suitable verification process, for all alloy steel piping components in hydrogen service that are installed during maintenance.