Event
- Event ID
- 257
- Quality
- Description
A truck transporting a pallet of 30 compressed hydrogen cylinders was traveling on a highway when gas started leaking from the welded pipe. The fire department ordered the hydrogen to be released to the atmosphere. The leak was caused by poor construction of the brazed welded pipes.
- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- leak no ignition
- Macro-region
- Asia
- Country
- Japan
- Date
- Component involved
- piping (weld)
- Failure mode
- rupture, no ignition
- Initiating cause
- manufacturing defect/error
- Root CAUSE analysis
The INITIATING CAUSE was a leak from pipe welds.
The KHK report identified the ROOT CAUSE in the bad welding quality (manufacturing cause). The road vibrations as contributing factor cannot be excluded.- Root causes
- Date entry in HIAD
- 30/08/2025
Facility
- Application
- Hydrogen transport and distribution
- Sub-application
- CGH2 cylinders truck
- Hydrogen supply chain stage
- All components affected
weld, pipe
- Process temperature range [C]
- ambient temperature (-50°C to +50°C)
- Location type
- Open
- Location
- highway or similar
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Emergency action
The fire deprtment intervened and decided to elease the whole content to the atmosphere.
Lesson Learnt
- Lesson Learnt
The bad quality of the brazed weld of the piping system was given as root cause. Nevertheless, road vibrations cannot be excluded as contributing factor.
A welded connection can be performed well enough to operate safe in stationary applications, while not resisting to stress and stress frequency typical from road vibrations. Several en-route connection failures in the PHMSA database are attributed to road vibrations.
This incident occurred in the 60’. More recent regulations prescribe minimal resistance requirements for components exposed to mechanical vibrations.
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Release temperature [°C]
- 25
- Probable IGNITION SOURCE
References
- Sources categories
- KHK
- Reference & weblink
High Pressure Gas Accident Cases Database of the KHK (High Pressure Gas Safety Association):
https://www.khk.or.jp/public_information/incident_investigation/hpg_inc…
(accessed May 2025)
