Event
- Event ID
- 372
- Quality
- Description
A liquid hydrogen tanker was returning to base terminal after having delivered at a space centre, when the driver noticed excessive venting of hydrogen gas vapour from the rear . The driver pulled off the road at a safe location and discovered that the vent valve had opened due to vibration. The driver closed the valve and continued safety back to the base.
An inspection of the valve found a crack in the silver braze on the valve stem tube, which caused the venting. The valve was removed for repair and the tanker was returned to service.- 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
- valve (generic)
- Failure mode
- leak, no ignition
- Initiating cause
- loss of tightness (road vibrations)
- Root CAUSE analysis
The INITIATING CAUSE was a leak through the vent valve.
The report provides two reasons for the leakage: (i) the opening of a vent valve due to vibration and (ii) a crack in the pipe. It is also unclear how a leak through a crack in a pipe could be stopped by closing a valve.
Therefore, the ROOT CAUSE can be attributed to a mechanical/material failure and to design shortcoming.- 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
vent valve, vent pipe
- Process temperature range [C]
- cryogenic temperature (below -50°C)
- Process pressure range [MPa]
- low to medium pressure (below 2 MPa)
- Location type
- Open
- Location
- highway or similar
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Currency
- US$
- Property loss (onsite)
- 8
- Post-event summary
A negligible amount of hydrogen was released.
- Emergency action
The leaking valve was closed by the driver.
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Probable IGNITION SOURCE
References
- Sources categories
- PHMSA
- Reference & weblink
Report I-1994041432 of the US Pipeline and Hazardous Materials Safety Administration PHMSA:
https://portal.phmsa.dot.gov/analytics/saw.dll?Portalpages&PortalPath=%…
(accessed September 2024)
