Event
- Event ID
- 378
- Quality
- Description
An empty liquid hydrogen tanker was returning to the base terminal after having delivered at a customer (approximately 4 hour and 200 miles). The drivers noticed vapour coming from the vent stack at the rear of the tanker. They stopped the vehicle and discovered that the vent valve had vibrated open since the last safety check. They closed the valve, ensured that everything else was safe and secure, and continued to the base terminal.
No defects were found after inspection at the terminal.- 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 the slightly opening of a valve due to road vibration.
The ROOT CAUSE was a design which did not took into account the whole range of mechanical solicitations which the pressure control system of the trailer could experiment when travelling.
- 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
- 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)
- 4
- Emergency action
The leaking valve was closed by the driver.
Lesson Learnt
- Lesson Learnt
This case, as several similar one, could have a lesson learnt similar to case 70
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Probable IGNITION SOURCE
References
- Sources categories
- PHMSA
- Reference & weblink
Report I-1992120298 of the US Pipeline and Hazardous Materials Safety Administration PHMSA:
https://portal.phmsa.dot.gov/analytics/saw.dll?Portalpages&PortalPath=%…
(accessed September 2024)
