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Clean Hydrogen Partnership

Over-pressurisation of a LH2 tanker

Event

Event ID
482
Quality
Description

When travelling to a customer, a liquid hydrogen tanker experienced a slight tank pressure increase due to an improper cooling down. The driver was carefully monitoring the pressure and when he observed the pressure rise about the normal level, he called the central logistics contact and reported the situation. The driver was advised to manually operate a hydrogen vent to re-stabilise the internal pressure. After having succeeded in doing so, the driver could restart without no further pressure problem during the trip (approximately 7 hr).

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
LH2 tank (road tanker)
Failure mode
manual venting
Initiating cause
over-pressurisation (wrong operation)
Root CAUSE analysis

The INITIAL CAUSE was over-pressurisation of the LH2 tank, which caused an intervention of the drivers to reduce pressure.
The ROOT CAUSE is reported as an inadequate cooling down procedure before filling.

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

vacuum thermal insulation

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)
200
Post-event summary

1.3 kg hydrogen were released.

Emergency action

The driver was carefully monitoring the pressure and when he observed the pressure rise about the normal level, he called the central logistics contact and reported the situation, was advised to manually operate a hydrogen vent to re-stabilise the internal pressure. After having succeeded in doing so, the driver could restart without no further pressure problem during the trip

In-depth data

Release type
gas
Involved substances (% vol)
H2 100%
Released amount (kg)
1.3
Probable IGNITION SOURCE

References

Sources categories
PHMSA
Reference & weblink

Incident I-1996110732 of the US Pipeline and Hazardous Materials Safety Administration PHMSA:
https://portal.phmsa.dot.gov/analytics/saw.dll?Portalpages&PortalPath=%…
(accessed September 2024)