Natural events such as earthquakes, floods, and lightning can cause accidents in oil and gas transport pipelines with potentially adverse secondary consequences to the population, the environment, or the industrial activity itself. Such accidents are commonly referred to as natech accidents. In order to better understand the dynamics and possible impact of pipeline natech accidents, Action A6 under the EPCIP 2012 Programme aims at analysing accidents caused by natural disasters in oil pipelines.
In the first twelve months of the study, European and U.S. pipeline incident data sources were evaluated and data was collected for further analysis to identify the main accident triggers, system strengths and weaknesses, consequences and lessons learned. Because publicly available European pipeline incident data is limited and data on individual accidents of concern for the study is scarce, public U.S. pipeline incident data was included in the study to obtain information beneficial for the safety of pipeline systems in Europe. Although Action A6 focuses on oil transmission pipelines only, natural gas pipeline incidents were also considered in the data collection due to the abundance of accident data available.
The information sources considered for this study were: the incident database of the Pipeline and Hazardous Safety Administration of the U.S. Department of Transportation, the database of the U.S. National Response Center, the French ARIA database, and information from EGIG and CONCAWE for Europe.
A database-driven incident data analysis system was developed to rapidly review and categorise the vast amount of incident records according to their causes, dynamics and consequences. Using an automated data-mining process followed by a peer-review of the record data, the pipeline natechs in the database were identified and extracted. The outcome of this process is a fully reviewed and categorised incident database which contains authoritative information on ca. 1,850 pipeline natechs worldwide. As a by-product of the data collection process, the database also includes over 800,000 records involving incidents from all causes in industrial facilities and pipelines (both on- and offshore), and transportation activities. This information is available for future studies in these application areas.
The results of the analysis of the identified data indicate that natural hazards are a non-negligible threat to pipelines transporting hazardous materials. The analysis of the U.S. data set shows that geological hazards triggered 37% of the onshore pipeline natechs analysed. This is followed by meteorological (29%), hydrological (14%), and climatic (14%) hazards. Landslides are the main geological hazard with 46% of the geological incidents, whereas earthquakes represent only 9% within the category. Among meteorological hazards, lightning is the major hazard with 36% of the incidents. 86% of the hydrological hazard related natechs are found to be due to floods. Overall, cold weather related hazards (frost, low temperatures) make up 94% of the pipeline natechs
caused by adverse climatic conditions. The current level of uncertainty in the analysed data is estimated as 24%.
In terms of consequences, 55% of the U.S. pipeline natechs involved natural gas, while 45% concerned pipelines transporting other types of substances (mostly crude oil and other hydrocarbons). For natural gas incidents ignition occurred in about 25% of the analysed cases, compared to about 8% for other substances. The likelihood of explosions was much lower, 3% for natural gas, and 2% for other substances. Overall, the number of fatalities and injuries was low, with only one case of a high number of injuries. While this incident was due to multiple pipeline breaks caused by wide-scale flooding it clearly demonstrates the potential for a major impact on the population of Natech events. More than two thirds of the releases from ruptured pipelines entered inland water bodies, followed by on-land releases (25%). The combined property damage
due to onshore pipeline natech events amounts to 650 million USD (in 2012 USD).
In contrast to the U.S., the data collection process for Europe was severely hampered by the lack of publicly available pipeline incident information. Generally, for Europe only overview data could be found, whose level of detail was not sufficient to allow an in-depth analysis of incident causes, dynamics and consequences. It would be desirable that information on pipeline incidents and their consequences be collected at a central level in Europe and made available for lessons-learning research. Using the limited European data available, the analysis results show that landslides and floods seem to pose the biggest threat to both oil and gas pipelines in Europe. Lightning is also a non-negligible threat with a high ignition probability in case of gas releases, as well as cold weather, which was identified as the main hazard for the French pipeline natech accident data set.
In the 12 months following this report the in-depth analysis of incident data will be continued with a view to identifying impact and failure modes and lessons learned for future accident prevention and consequence mitigation will also be identified. Based on this, recommendations for Natech scenario development in pipelines and for the formulation of prevention and mitigation measures will be prepared.
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