Event
- Event ID
- 463
- Quality
- Description
Minor leak in the break-away coupling for 35MPa dispenser of a refuelling station for buses.
The leak developed in the break-away coupling during a controlled test refuel. The test was attended by the station operator’s staff. The leak occurred as the temperature was decreasing (the hydrogen is pre-chilled to between -33oC and -40oC prior to entering the dispenser).The dispenser was taken out of service until a replacement break-away coupling was installed by the manufacturer. The 70MPa dispenser remained operational.
The dispenser system had been leak-tested during the installation/commissioning phase, however this had only been carried out at ambient temperature. It is believed that the leak was only present at low temperature.- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- leak no ignition
- Macro-region
- Europe
- Country
- United Kingdom
- Date
- Component involved
- dispenser (breakaway)
- Failure mode
- leak, no ignition
- Initiating cause
- material degradation (cryogenic temperature)
- Root CAUSE analysis
Shortcoming in the testing procedure did not allowed for the detection of a small leak.
- Root causes
- Date entry in HIAD
- 01/01/2019
Facility
- Application
- Hydrogen refuelling station
- Sub-application
- HRS
- Hydrogen supply chain stage
- All components affected
break-away
- Process temperature range [C]
- ambient temperature (-50°C to +50°C)
- Process pressure range [MPa]
- medium to high pressure (10 to 50 MPa)
- Location type
- Open
- Location
- populated area
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Post-event summary
The 35MPa dispenser was taken out of service until a replacement break-away coupling was installed by the manufacturer. The 70MPa dispenser remained operational.
No injury or harm to any people.
Lesson Learnt
- Lesson Learnt
Leak test at ambient temperature may not be sufficient to identify leaks within systems cooled during normal operation. It is proposed that a leak test is conducted during commissioning at the minimum temperature expected during operation.
A more refined automated leak detection logic needs to be developed and is under discussion with the manufacturer in order to capture this type of leaks when trained personnel are not present.
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Release temperature [°C]
- 25
- Release pressure [MPa]
- 35
- Probable IGNITION SOURCE
References
- Sources categories
- Investigation report
- Reference & weblink
Provided to JRC by the operator of the facility (confidential)
