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 (No additional details provided)
- Macro-region
- North America
- Country
- United States
- Date
- Main component involved?
- Valve (Generic)
- How was it involved?
- Leak & Formation Of A Flammable H2-Air Mixture
- Initiating cause
- Loss Of Tightness (Road Vibrations)
- Root causes
- 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.
Facility
- Application
- Hydrogen Transport And Distribution
- Sub-application
- LH2 tanker
- Hydrogen supply chain stage
- Hydrogen Transport (No additional details provided)
- All components affected
- vent valve, vent pipe
- Location type
- Open
- Operational condition
Emergency & Consequences
- Number of injured persons
- 0
- Number of fatalities
- 0
- Environmental damage
- 0
- Currency
- US$
- Property loss (onsite)
- 8
- Property loss (offsite)
- 0
- Post-event summary
- A negligible amount of hydrogen was released.
Event Nature
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Presumed ignition source
- No ignition
References
- Reference & weblink
Report I-1994041432 of the US Pipeline and Hazardous Materials Safety Administration PHMSA: <br />
https://portal.phmsa.dot.gov/analytics/saw.dll?Portalpages&PortalPath=%… />
(accessed September 2024)
JRC assessment
- Sources categories
- PHMSA
