Leakage at a hydrogen refilling station in a airport

This near miss occurred at the at an airport's hydrogen refilling station.
Around 4:30 a.m., the hydrogen detector of the station was triggered and a sound and light alarm were activated. The hydrogen filling station was up in safe mode and the hydrogen storage system isolated. The connection pipes were purged via the vent and the power supply cut off.
An on-call technician from the company in charge of managing the station arrived at 6:15 a.m., confirmed that the installation has been made safe and stopped the alarm.
The leak was located on the compressor’s filter. This filter was located in a restricted and confined space controlled by a gas detector. The detector triggered the alarm because the concentration of hydrogen in the atmosphere had reached its safety limit (25% of the lower explosive limit). Nevertheless the amount of dispersed hydrogen have been very low. The defective filter was replaced.

The initiating cause of the event was a loss of confinement of a gasket inside the filter of the hydrogen compressor.

Compressors, filter, gasket

Approximately one month before, another hydrogen leak had affected the same HRS (See HIAD 1063)

The supplier was officially contacted to identify the causes of this loss of tightness. The station was put not back in service till the supplier replied.

The leaking hydrogen triggered the alarm of the safety detector in place, and the station was put in safe mode, apparently automatically, although the source of the event does not explicitly says so.

Following the event, the airport operator asked the hydrogen station operator:
• to inform local companies of risk management at hydrogen production facilities;
• to adjust the on-site intervention of technicians according to the need of the local companies.