Controls for Hydrogen Systems

Purging

One should always assume that hydrogen is present and verify that the system has been purged to the appropriate level when performing maintenance on a hydrogen system.
Likewise, one should always assume that air is present and verify that the system has been purged to the appropriate level when reintroducing hydrogen into a system.

Hydrogen storage facilities should be provided with adequate ventilation for both normal operating conditions and emergency situations.
Vent lines for hydrogen (including pressure relief lines and boil-off from cryogenic systems) should be vented to an appropriate exhaust system or a safe outside location.
The vent should be designed to prevent moisture or ice from accumulating in the line.
Unused hydrogen should be disposed of by venting or possibly flaring.