During inspection of a hydrogen make-up compressor, it was discovered that a 1/4” stainless steel screw and nut that mounted a temperature gauge to a stainless steel pipe was resting against the side of a schedule 160 high-pressure hydrogen pipe. Constant vibration of the process equipment had caused the bolt to rub a hole in the high-pressure suction piping, resulting in the release of make-up hydrogen. The pipe was out of sight, and the problem was identified by an employee who heard the whistling sound of escaping hydrogen. The compressor was taken offline and depressurized.
Hydrogen distribution lines should be designed and carefully inspected to ensure process equipment in the area is correctly and safely installed. Equipment subject to vibration should not be placed in contact with hydrogen lines or with other equipment.
If equipment is moved or rearranged, the hydrogen system should be reinspected as per the above.