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Clean Hydrogen Partnership

Over pressurisation of a LH2 trailer

Event

Event ID
1112
Quality
Description
An LH2 trailer-tractor was returning to the base after a hydrogen delivery at a customer. The trailer was almost empty. Nevertheless, the drivers noticed an increase in the trailer internal pressure. They notified the company support team and pulled into a truck parking place, to avoid the risk of having the safety vent open while traveling. They then performed a controlled, manual venting of the trailer, going from 45 psig (3.1 barg) to 8 psig (0.6 barg). They then returned to the base without further incident.
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?
Lh2 Tanker
How was it involved?
Manual Venting
Initiating cause
Over-Pressurisation (Wrong Operation)
Root causes
Root CAUSE analysis
The INITIAL CAUSE was over-pressurisation of the LH2 tank, which caused an intervention of the drivers to reduce pressure.
BY using as proxy several similar events, ROOT CAUSE could be tentatively attributed to the failure to 'stabilise' the pressure of the tanker after delivery and before leaving customer's site. This is a procedure aiming at avoiding over-pressurisation by cold gaseous hydrogen during the return travel.

Facility

Application
Hydrogen Transport And Distribution
Sub-application
LH2 tanker
Hydrogen supply chain stage
Hydrogen Transport (No additional details provided)
All components affected
vacuum thermal insulation
Location type
Open
Operational condition
Pre-event occurrences
The trailer was almost empty, after delivery.

Emergency & Consequences

Number of injured persons
0
Number of fatalities
0
Environmental damage
0
Currency
US$
Property loss (onsite)
1800
Property loss (offsite)
0
Post-event summary
A negligible amount of hydrogen was released.

Event Nature

Release type
gas
Involved substances (% vol)
H2 100%
Actual pressure (MPa)
0.3
Presumed ignition source
No ignition

References

Reference & weblink

Incident I-2000070308 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