Fire in a hydrogen refuelling station

A hydrogen leak in the hydrogen compressor unit of a filling station ignited causing the shut down of the whole station.
The loss of containment was due the failure of a tie rod (diameter ~64mm) , which had the structural function holding together all compressor parts. The failure caused an hydrogen leak at high pressure. A large amount of hydrogen was released from the compressor to the compressor container within a short time, ignited followed by a deflagration or explosion inside the container. A part of the tie rod was shot to the side wall of the container. One door of the container was detached and was stopped by the fence in 10 m distance.
Firgefighters were on site within 10 min and got quickly the fire under control .
No injury, considerable material damage, limited to two containers.

INITIATING CAUSE:
Mechanical failure of a structural component of the hydrogen compressor.

ROOT CAUSE :
The metallographic investigation revealed that the tie rod failed by inter-granular brittle fracture, suggesting a wrong thermal treatment of the rod material.

tie rod,
compressor

The hydrogen refuelling station had been opened a week before the incident.
A CGH2 tube trailer was on site, probably to deliver hydrogen to the HRS>

DESCRIPTION OF THE REFUELLING STATION
The fuelling station delivers LNG and hydrogen. The hydrogen part is newer.
It has two dispensers to provide 350 and 700 bar hydrogen serving private cars, buses, special vehicles to heavy trucks.
Its capacity is 500 kilograms per day, able to refuel 10 to 20 commercial vehicles.

Damage unknown. From the pictures provided by the sources, the compressor housing and its contents appears destroyed.
The refuelling station operator plans to resume supplying vehicles with hydrogen in the autumn.
The compressor manufacturer checked the three other systems installed in other hydrogen refuelling stations.

The safety measures in place worked as intended.
A preliminary conclusion from this and similar events is that the individual technologies belonging to the hydrogen supply chain are still not yet fully mature. Possible causes are (i) the limited field experience gained so far, and (ii) the small amount of components produced, which hinders fully fledged quality insurance.

The compressor manufacturer made a recall action of all machines with tie rods of the same batch. It introduced also an ultrasonic testing of all newly produced tie rods.