Event
- Event ID
- 1141
- Quality
- Description
- The drivers of a CGH2 tube trailer-tractor was travelling to a delivery. they stopped to perform a visual walk-around inspection of the vehicle and discovered an audible leak coming from the neck threads of a tube. They notified the company, which dispatched a local emergency response team. The team proceeded to vent the hydrogen in the leaking tube. The trailer was returned to the shipping location to disable the defective tube valve.
- 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?
- Joint/Connection (Threated)
- How was it involved?
- Leak & Formation Of A Flammable H2-Air Mixture
- Initiating cause
- Material Degradation (Generic)
- Root causes
- Unknown (No additional details provided)
- Root CAUSE analysis
- The INITIATING CAUSE was probably the loosening of a threaded connection of a valve, probably due to road travel vibrations.
The ROOT CAUSE is not provided.
Facility
- Application
- Hydrogen Transport And Distribution
- Sub-application
- CGH2 tube trailer
- Hydrogen supply chain stage
- Hydrogen Transport (No additional details provided)
- All components affected
- Threaded Connection
- Location type
- Open
- Operational condition
- Description of the facility/unit/process/substances
- DESCRIPTION OF THE UNIT
The trailer consisted of ten steel tubes, with a capacity of 12000 gas cubic feet each (ca. 30.5 kg).
The pressure is not provided, but from Linde webpages it can be deduced a pressure of 180 to 250 bar for these steel cylinders.
The nominal trailer gas capacity is also the value provided by PHMSA for the released amount. However, the report states also a 'amount in package' of only 77.8 gas ft3, which would indicate an empty tube. Since it is also stated tht the trailer was travelling to a delivery, it could not have been empty. This is contradictory and illogic, and has been neglected in HAID encoding.
Emergency & Consequences
- Number of injured persons
- 0
- Number of fatalities
- 0
- Environmental damage
- 0
- Currency
- US$
- Property loss (onsite)
- 0
- Property loss (offsite)
- 0
Lesson Learnt
- Lesson Learnt
- The preventing/mitigating measures worked well: (i) the regular inspection by drivers along the route, and (ii) the emergency handling by depressurising the leaking tube and releasing its content to the atmosphere.
The loosening of threaded connection due to road vibration is a common glitch. It is however unclear, in this and similar events, how this could be avoided. Is the root cause related to shortcoming when installing / maintaining the connections, to unexpected road conditions during travel, or to a design unable to guarantee tightness during travelling?
Event Nature
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Released amount
- 30.5
- Actual pressure (MPa)
- 18
- Design pressure (MPa)
- 18
- Presumed ignition source
- No ignition
References
- Reference & weblink
Incident I-2013080039 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
- Sources categories
- PHMSA
