Hydrogen release when refuelling a train

The release occurred during refuelling of the mobile storage system. This operation was part of a series of tests aiming at verifying the tightness of the system.
When opening a valve to connect the dispenser to the high-pressure mobile storage system, a ferrule fitting failed, a tube was bended, and 450 bar hydrogen was released to the atmosphere.
The operator closed the valve as soon as possible. The release lasts a few seconds.
The loud noise of the high-pressure release caused hearing loss of different severity to the people that were in the area.
One person had a dislocation when running to escape from the incident.


The incident took place when preparing the dispenser for the tightness tests of the hydrogen powered train. Tightness tests up to a maximum of 450 bars had to be done as part of the factory tests of the train. A HRS developed for the project was expected to be used for those tests. Nevertheless, the development of that HRS has been delayed, and it was not available for the test. A dispenser and a 450 bar storage system from different manufacturer was rented instead.
The dispenser had been used with no incident at pressures up to 200 bar to fuel the train during previous tests. Some days before the incident, the 450 bar storage system was connected to the dispenser for a short period of time to the check the equipment, with no incident.
On the day of the incident, as soon as a valve in the storage system was opened to connect the dispenser to the storage system, the ferrule fitting of a pipe failed, and high-pressure hydrogen was released.

THe INTIATING CAUSE was a leack caused by the failing of the joint when testing a dispenser.

Two causes have been deemed most likely:
(1) An incorrect fixing of the ferrule fitting. The failed fitting was not originally part of the dispenser. It was added on site, and not tested.
or
(2) Vibrations during transportation. After being commissioned in manufacturer's facilities, the dispenser was moved to another two locations before going back to manufacturer location, traveling around 200 km. The dispenser was not checked after transportation.

The ROOT CAUSE could lie in (1) a deviation from the correct procedure during installation or (2) a missing step in the inspection of components (connections) when deviating from normal operations.

pipe fitting, mobile connection

The incident took place when preparing the dispenser for the tightness tests of the hydrogen powered train. Tightness tests up to a maximum of 450 bars had to be done as part of the factory tests of the train. A HRS developed for the project was expected to be used for those tests. Nevertheless, the development of that HRS has been delayed, and it was not available for the test. A dispenser and a 450 bar storage system from different manufacturer was rented instead.
The dispenser had been used with no incident at pressures up to 200 bar to fuel the train during previous tests. Some days before the incident, the 450 bar storage system was connected to the dispenser for a short period of time to the check the equipment, with no incident.
On the day of the incident, as soon as a valve in the storage system was opened to connect the dispenser to the storage system, the ferrule fitting of a pipe failed, and high-pressure hydrogen was released.

Release lasted a few seconds. No information on released quantity is available.
One person suffered a certain level of hearing loss. Some people suffered from temporary hearing problems, and evolved positively.
One person had a slight dislocation when running to escape from the incident.
No damage was caused to the equipment apart from the bended tube.

The following actions were taken:
- To review ferrule fittings with measurement gauges.
- To perform tightness tests to the dispenser.
- To stablish procedures for checking the equipment after repair or transportation.
- To use of hearing protection.