Event
- Event ID
- 375
- Quality
- Description
- An empty liquid hydrogen tanker was returning to home terminal after having delivered at a space centre. A motorist passed by and pointed to the rear of the tanker. The driver stopped the vehicle and noticed that a small amount of hydrogen vapour was coming out of the vent stack.
The driver found that the vent valve had vibrated open and was releasing hydrogen vapour through the vent stack. The driver secured the valve and returned to the base with no further incident. No defects were found after inspection at the home terminal. - 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
- Unknown (No additional details provided)
- Root CAUSE analysis
- The INITIAL CAUSE was the release of a small quantity of hydrogen through a partially loose vent valve.
The ROOT CAUSE is not given. Similar cases have been attributed to road vibration (shortcoming In design), but it could be as well related to a non-completely tight closure of the vent valve after operation (procedure not properly followed)
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
- Location type
- Open
- Operational condition
- Pre-event occurrences
- Probably the tanker was not containing LH2, but only gaseous hydrogen, after having delivered hydrogen to a customer site.
Emergency & Consequences
- Number of injured persons
- 0
- Number of fatalities
- 0
- Environmental damage
- 0
- Currency
- US$
- Property loss (onsite)
- 1
- Property loss (offsite)
- 0
- Post-event summary
- 720 kg of hydrogen were released.
Lesson Learnt
- Lesson Learnt
the mitigation procedure in place was applied properly. This event could be also classified as a near-miss.
Event Nature
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Presumed ignition source
- No ignition
References
- Reference & weblink
Report I-1993050573 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
