Event
- Event ID
- 481
- Quality
- Description
A liquid hydrogen tanker was travelling to a customer when the driver noticed that hydrogen release was occurring at the trailer vent stack. The driver stopped the vehicle in a safe location and investigated the cause discovering that the vent valve had opened slightly. The driver could stop the venting by closing the valve tightly. The tanker could deliver at destination without further venting (total trip approximately 3 hours).
Back to the home terminal, an inspection found that a small amount of ice had most likely prevented full closure of the vent valve. This ice formation had occurred when equilibrating internal pressure before the start of the trip. When the ice melted during the travel, the vent opened slightly, resulting in a venting.- 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
- rupture, no ignition
- Initiating cause
- ice formation
- Root CAUSE analysis
The INITIAL CAUSE a not tight manual vent valve.
The ROOT CAUSE was the formation of ice during preparation of the load for the trip. This could hint at incomplete procedural guidelines.- Root causes
- Date entry in HIAD
- 01/01/2025
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
- Pre-event occurrences
The LH2 tanker was full
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Currency
- US$
- Property loss (onsite)
- 100
- Post-event summary
0.7 kg hydrogen were released.
- Emergency action
The driver stopped the vehicle in a safe location, discovered that the vent valve had opened slightly, closed it and stopped the leak . The trailer could deliver at destination without further venting
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Released amount (kg)
- 0.7
- Probable IGNITION SOURCE
References
- Sources categories
- PHMSA
- Reference & weblink
Incident I-1996110733 of the US Pipeline and Hazardous Materials Safety Administration PHMSA:
https://portal.phmsa.dot.gov/analytics/saw.dll?Portalpages&PortalPath=%…
(accessed September 2024)
