Event
- Event ID
- 368
- Quality
- Description
During preparations for off-loading of a commercial tanker, the trailer experienced an overpressure causing the 50 psig (ca. 3.5 bar) relief valve to open and also the rupture of the 70 psig (ca. 4.8 bar) burst disc. Hydrogen was vented through the vent valve and the disc. A vapour cloud of about 25 feet in diameter resulted. Examination later also showed cracks in the carbon steel vent line.
- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- leak no ignition
- Macro-region
- North America
- Country
- United States
- Date
- -
- Component involved
- PRD (generic)
- Failure mode
- correct activation & venting
- Initiating cause
- over-pressurisation (wrong operation)
- Root CAUSE analysis
The liquid phase valve into the trailer transfer build-up coil was opened prior to opening the gas pressurization valve. Opening the pressurization valve resulted then in unrestricted large flows into the tank causing excessive pressures which opened the relief valve and ruptured the burst disc. Vibrations during transit may have caused the liquid phase valve to open. The trailer was almost completely full of liquid hydrogen which contributed to the accident. The flow of cold fluid caused the cracks in the carbon steel vent line.
- Root causes
- Date entry in HIAD
- 16/11/2024
Facility
- Application
- Hydrogen transport and distribution
- Sub-application
- LH2 tanker
- Hydrogen supply chain stage
- All components affected
PRV; burst disc
- Process temperature range [C]
- cryogenic temperature (below -50°C)
- Process pressure range [MPa]
- low to medium pressure (below 2 MPa)
- Location type
- Open
- Location
- industrial area
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Release pressure [MPa]
- 0.3
- Probable IGNITION SOURCE
References
- Sources categories
- ORDIN
- Reference & weblink
Mishap no 16 in
P. L. Ordin, Review of hydrogen accidents and incidents in NASA operations, 1974, NASA TM X-71565
https://ntrs.nasa.gov/citations/19740020344
