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Clean Hydrogen Partnership

Overpressure damage in a testing facility

Event

Event ID
397
Quality
Description

During a leak check of a flash point material testing chamber, the chamber was inadvertently over-pressurised with GH2. The glass port in the door burst, causing damage to the chamber and to the facility.

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
reactor / oven / furnace / test chamber
Failure mode
internal explosion
Initiating cause
over-pressurisation (wrong operation)
Root CAUSE analysis

The ROOT CAUSE was design deficiencies in the test chamber and installation. The pressure source was 150 psig (11 bara) and the chamber working pressure was 16.5 psia (0.4 bara). There was no pressure regulator on the source and no pressure relief valve on the chamber. The pressure gauge was installed between two chambers with shutoff valves to each, thus allowing erroneous pressure readings under dynamic pressure conditions. CONTRIBUTING CAUSE was a failure to follow procedures in checking leaks.

Root causes
Date entry in HIAD
01/11/2025

Facility

Application
Laboratory / R&D
Sub-application
material testing
Hydrogen supply chain stage
All components affected

testing chamber

Process temperature range [C]
ambient temperature (-50°C to +50°C)
Location type
Confined
Location
unknown
Operational condition

Emergency & Consequences

Number of fatalities
0
Number of injured persons
0

In-depth data

Release type
gas
Involved substances (% vol)
H2 100%
Release temperature [°C]
25
Release pressure [MPa]
0.04
Probable IGNITION SOURCE
Explosion type

References

Sources categories
ORDIN
Reference & weblink

Mishap no 57 in
P. L. Ordin, Review of hydrogen accidents and incidents in NASA operations, 1974, NASA TM X-71565
https://ntrs.nasa.gov/citations/19740020344

Hankinson and Lowesmith, Qualitative Risk Assessment of Hydrogen Liquefaction, Storage and Transportation, FCH JU project IDEALHY, Deliverable 3.10 (2013)
confidential
(accessed October 2025)

Lowesmith et al., Safety issues of the liquefaction, storage and transportation of liquid hydrogen: An analysis of incidents and HAZIDS, Int. J. Hydrogen energy (2014) https://doi.org/10.1016/j.ijhydene.2014.08.002