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Clean Hydrogen Partnership

Manual venting from a LH2 tanker in transit

Event

Event ID
203
Quality
Description

The pressure building valve opened due to vibration from the road, causing the build-up of the internal pressure. The drivers performed a hydrogen venting and re-sealed the valve.

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 (pressure building)
Failure mode
leak, no ignition
Initiating cause
over-pressurisation (road vibrations)
Root CAUSE analysis

The INITIATING CAUSE was the loosening of a valve due to vibration while travelling.
The ROOT CAUSE could be attributed to a shortcoming in the design of the connections or to the failing to tighten correctly the valve.

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

pressure building 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)
0
Emergency action

manual venting and re-sealing of the valve

Lesson Learnt

Lesson Learnt

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 t o transport , transfer and store hydrogen outdoors away from occupied areas."

In-depth data

Release type
gas
Involved substances (% vol)
H2 100%
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)