Fire while transferring LH2

A small fire developed at the connection hose between the LH2 delivery trailer and the customer stationary tank. The driver intervened to isolate the hose first on the delivery side, and then at the receiving tank.
The fire lasted approximately 15-20 minutes.
The investigation revealed that customer tank hose seal was not meeting the design specification.

DETAILED DESCRIPTION
(A) When approximately half of the loading had been transferred, the driver noticed a small leak developing at the connection between the hose and the customer tank.
(B) The driver started the process to shut down the fill, by closing the trycock valve and shutting down the delivery pump (a trycock valve is a manual valve used to check the filling level and to stop the overall filling). Meanwhile, the leak rapidly accelerated and ignited. The driver quickly got back to trailer and shut down the truck.
(C) With the pump down and the trycock valve closed, the supply side of the transfer was isolated. The fire slowed significantly, but was still burning, probably due to liquid remained in the hose. The driver was then able to close the top fill valve at the receiving tank. In this way the hose was isolated at both sides.
(D) The driver notified the customer and the emergency response services.
(E) The driver performed a helium purge and disconnected the hose under emergency services supervision.

The INITIATING CAUSE was a hydrogen leak from a connection.

The emergency procedure was followed successfully

The ROOT CAUSE was the use of a seal for the connection not meeting the design specification. This could be attributed to an to an installation error.

seal, connection, hose