One afternoon, a hydrogen-monitoring system alarm sounded. The system isolated the building hydrogen gas distribution system from the source and purged the distribution piping with argon. Activities were terminated and personnel were immediately evacuated.
Prior to re-entry, the hydrogen system was walked down to ensure that it was in a safe state and that the remote indicator showed no hydrogen present in the facility. Normal operations were suspended until the cause of the alarm could be determined.
The cause of the alarm was not escaping hydrogen gas, but drift in one of the eight monitoring system sensors. The sensor was recalibrated and the monitoring system determined to be functioning properly. The gas distribution system was recharged with hydrogen and verified as ready to resume normal operations.
Frequently inspect and maintain all elements of hydrogen-related systems.