Release and fire at a flexible hose during hydrogen transfer

A hydrogen leak occurred at a tube bundle container at the loading and unloading bay of a PSA (Pressure Swing Adsorption) hydrogen production plant.
During the hydrogen filling process, a worker in charge noticed the leak in the filling hose of one of the trailers after an abnormal noise. After 22s, the hose connected to that trailer broke, and moved rapidly towards another trailer. less than 5 minutes later, the broken hose was flung in front of the other trailer and the leaking hydrogen gas started to burn. After only 5s, the hydrogen leaking from the loading and unloading ports on first trailer caught fire and burned.
The metal hose fractured, the hose was flung around, and hit an object, which caused the spark which ignited the hydrogen.
This is a case of delayed ignition: from the moment in which the hydrogen leak was detected to the first ignition took 5 minutes.
The fire resulted in damage to the pipes, valves and other accessories of the two hydrogen bundle containers.

the INITIATING CAUSE of the fire was the rupture of a flexible filling hose. The hose could not meet the working pressure of 22 MPa. When the pressure reached 17.5 MPa, the hose broke off, causing a release of hydrogen. The company bought and used metal hoses produced by a machinery fittings manufacturing company. They were cheap and burst when they were filled to 7.5MPa pressure. This reveals that the enterprise's quality and safety awareness was not strong, the risk assessment was not thoroughly performed, the control and the mitigation measure was not in place or not well-designed.

flexible, trailer

Approximately 26 Meuro

The emergency measures were taken effectively. The fire was completely extinguished approximately 1 hour after its start.

The investigation found the company was using cheap flexible which were not designed for the pressure used during hydrogen transfer. This reveals that the enterprise's quality and safety awareness was not strong, the risk assessment was not thoroughly performed, the control and the mitigation measure was not in place or not well-designed. The consequence of the incident could have been much higher, if the hydrogen would have cumulated in the semi-confined structure neighbouring the trailers.
This could be an example of neglecting basic safety engineering principles to abate cost.