Fire from a Hydrogen Pipeline
Fire broke out along a transition corridor combining several underground pipelines transporting hazardous substances, including hydrogen, kerosene and ethylene oxide. The fire was brought under control within a few minutes thanks to the limited size of the leak. Though no noteworthy consequences were observed, the incident was still taken seriously, given the presence of other pipes merged into the same corridor, some of which were transporting toxic gases.According to the appropriate inspectorate, a hydrogen (H2) leak on an underground pipeline had been ignited by welding work performed nearby. Differential ground settlement with local deformation of the pipeline at the level of a cathodic protection system had caused the H2 leak. The type of ground (i.e. sandy soil) facilitated this settlement due to the presence of heavy equipment on the ground surface (e.g. drainage pump, construction vehicles) used for earthworks conducted to lay a new kerosene pipe.
Event Date
October 12, 2007
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
The leakage was caused by a mix of several tension factors executed on the hydrogen pipeline. The predominant stressing factor was the gradual settlement of the pipeline and the earth surrounding it. The settlement took place over a time span of several years and resulted in the bending of the pipeline at a spot where the pipeline got stuck on a fixed structure, e.g. a feed through in which the pipeline enters a building. The bending forces caused tensions on the CP coupling nearby in the pipeline, which eventually started to leak. Other stressing factors that might have contributed to the occurrence of the accident were un-allowed heavy traffic and the placement of heavy equipment on the soil covering the pipeline.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
Hydrogen underground pipeline
Storage/Process Medium
Actual Pressure
75
Design Pressure
75
Location Type
Location description
Inhabited Area
Pre-event Summary
The leakage lasted for at least several hours but it can not be excluded that it started weeks or even months prior to the discovery of the leak.The leak occurred at a specific weak spot in the pipeline in which tensions could mount, resulting in the partial failure of a so-called CP coupling.The escaping hydrogen gas was ignited on the 12th October 2007 by welding activities which at that time were taking place in the vicinity of the leak as part of a construction project to add another pipeline in the corridor
Consequences
Number of Injured Persons
2
Lessons Learned
Lessons Learned
Specific lessons (mostly of a technical nature): 1.Criteria had to be established for the quality of CP couplings in pipelines and the installation and maintenance conditions associated with them in order to safeguard that the couplings are not exposed to any type of stress during their operational lifetime. 2.Policies with regard to the measurement and interpretation of ground settlement had to be reassessed. 3.A strict surveillance policy had to be developed to prevent infringements on rules regulating activities on top of pipelines in order to prevent the possible damage of these pipelines. General lesson (of a organisational nature): 4.An abundant series of supervisors and inspectors on a project does not necessarily mean that the essential requirements to safeguard a safe environment are met. On the contrary.5.All parties involved in the management of the pipeline corridor (the management of the foundation as well as all individual pipeline operators) had to redefine supervision and inspection policies in order to get a clear division between each others tasks and responsibilities, particularly during construction activities in the pipeline corridor. The additional supervisory role of external parties, like notified bodies and independent supervisors had to be included in this survey of responsibilities.
Event Nature
Emergency Action
Because of the fact that at the start of the accident the nature of the escaping gas was unclear, several precautionary measures were taken by the police and the fire brigade. The inhabitants of the village nearby were advised to stay indoors for about three hours. Busy traffic on a nearby waterway to and from the Rotterdam harbour area was halted for several hours. After the conclusion that it was a hydrogen release and fire restrictions were lifted. Immediate actions: Repairing the pipeline, checking pipelines with similar constructions and tightening supervision during activities in the pipeline corridor.
Emergency Evaluation
Given the fact that hydrogen gas is not toxic, and that a limited gas escape and fire were concerned, there has been no imminent danger to people living nearby. Nevertheless, the incident has been classified as serious, because the gas escape could have been more extensive, and other transport pipelines that were lying nearby might have developed leaks for the same reason, which might have caused the release of poisonous gases.
Release Type
Release Substance
Hydrogen Release Concentration (%)
100.00
Release Duration (s)
10000
Release Amount (kg)
8.50
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Flame Type
Source Category
References
References
full report from ARIA data base
event no. 35860
brief description ARIA
event no. 35860