Release during CGH2 transfer

A CGH2 tube trailer was parked at the delivery site and was transferring gaseous hydrogen to a stationary storage system. The transfer hose failed releasing hydrogen, which ignited. The resulting fire melted the valves and rupture discs on all tubes. The emergency action plan was initiated, an immediate evacuation of the area was executed and local fire department notified. The fire was extinguished and evacuation over after several hours.

The INITIATING CAUSE was the rupture of the flexible hose.

The fire escalated from the hose to the trailer tubes. Their pressure relief system (burst disk) activated as expected in these cases, avoiding further escalation due to over-pressurisation of the tubes. However, the damage of additional valves on the trailer suggests a ROOT CAUSE in a shortcoming of a safety design of the transfer process, which did not consider this possibility and failed to guarantee fire protection to critical components.

flexible hose, valves, TPRD, tubes.

The only data known on the trailer is that it consisted of 34 tubes. Using similar cases as a proxy, tubes nominal pressure was very probably 180 bar, and trailer nominal transport capacity was approximately 250 - 300 kg of hydrogen. If the incident occurred at the start of the transfer, the whole content was lost, vented through the burst disk and the vent stack.

The emergency action plan was initiated, an immediate evacuation of the area was executed and local fire department notified. The fire was extinguished and evacuation over after several hours.