Event
- Event ID
- 207
- Quality
- Description
Pressure buildup in tank was manually vented by driver releasing 1000 cu ft (approximately 2.5 kg) of hydrogen.
- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- Macro-region
- North America
- Country
- United States
- Date
- Component involved
- LH2 tank (road tanker)
- Failure mode
- manual venting
- Initiating cause
- unknown
- Root CAUSE analysis
The INITIATING CAUSE was the over-pressurisation of the tank when returning empty of liquid hydrogen after delivery.
The ROOT CAUSE was probably a small shortcoming in the execution of the procedure for stabilisation of the tank pressure after delivery.
- Root causes
- Date entry in HIAD
- 20/01/2025
Facility
- Application
- Hydrogen transport and distribution
- Sub-application
- LH2 tanker
- Hydrogen supply chain stage
- All components affected
manual vent
- 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)
- 0
- Emergency action
manual venting
Lesson Learnt
- Lesson Learnt
This event could be considered almost a near miss. The safety procedure (manual venting) preventing the pressure to increase beyond the allowed value functioned as planned, avoiding uncontrolled hydrogen release.
Zalosh et al (see references), concluded their analysis of hydrogen transportation accidents till 1978 with the following conclusions:
"Finally, an encouraging aspect of the transportation incident compilation is that 71% of the hydrogen releases did not lead to an ignition. ... The relatively few ignitions may be due to either to lack of ignition sources or to the rapid dispersal of hydrogen into the atmosphere. In any event, the accident data provide further incentive to transport , transfer and store hydrogen outdoors away from occupied areas."
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Released amount (kg)
- 2.37442
- Probable IGNITION SOURCE
References
- Sources categories
- Zalosh
- Reference & weblink
Extract from Table III of Appendix A of Zalosh and Short
COMPARATIVE ANALYSIS OF HYDROGEN FIRE AND EXPLOSION INCIDENTS
Quarterly Report No. 2 for Period December 1, 1977 - February 28, 1978
https://www.osti.gov/biblio/6566131
(accessed September 2020)
