Age of pipeline systems unrelated to spill risk – new European study
European environmental and safety group CONCAWE recently released results of a new study, showing that there is no evidence that the aging of a pipeline system poses any greater level of spillage risk.
CONCAWE collected 39 years of spillage data on European cross-country oil pipelines with particular regard to spillages volume, clean-up and recovery, environmental consequences and causes of the incidents, it said.
The results have been published in annual reports since 1971. The latest report covers the performance of these pipelines in 2009 and a full historical perspective since 1971. The performance over the whole 39 years is analyzed in various ways, including gross and net spillage volumes and spillage causes grouped into five main categories: mechanical failure, operational, corrosion, natural hazard and third party. The rate of inspections by in line tools (intelligence pigs) is also reported.
Over 70 companies and agencies operating oil pipelines in Europe currently provide data for the CONCAWE annual survey. For 2009 data was received from 70 operators representing over 160 pipeline systems and a combined length of 34,643km, slightly less than the 2008 inventory.
There were minor corrections to the reported data. Seven operators did not report but none of these suffered a spill in 2009. Nevertheless they are not included in the statistics. The reported volume transported in 2009 was about 10% higher than 2008 which was unusually low.
Five spillage incidents were reported in 2009, corresponding to 0.14 spillages per 1000 km of line, well below both the 5-year average of 0.28 and the long-term running average of 0.53, which has been steadily decreasing over the years from a value of 1.2 in the mid 70s.
There were no reported fires, fatalities or injuries connected with these spills. The gross spillage volume was high mostly as a result of a single large spill.
One single spill accounted for 98.5% of the total gross spilled volume, the report said. Over the long term, less than 20% of the spillages are responsible for about 80% of the gross volume spilled.
Pipelines carrying hot oils such as fuel oil have in the past suffered from external corrosion due to design and construction problems. Most have been shut down or switched to cold service so that the great majority of pipelines now carry unheated petroleum products and crude oil. The last reported spill from a hot oil pipeline was in 2002.
Of the five reported incidents in 2009, four were related to mechanical failures and one was connected to undetected past third party activities (“incidental”), researchers said.
Over the long term, third-party activities remain the main cause of spillage incidents, although the number of events has progressively decreased over the years. Mechanical failure is the second largest cause of spillage. After great progress during the first 20 years, the frequency of mechanical failures has been on an upward trend over the past decade.
Most pipeline systems were built in the 60s and 70s. Whereas, in 1971, 70% of the inventory was 10 years old or less, by 2009 only 6% was 10 years old or less and 54% was over 40 years old.
However, this has not led to an increase in spillages.
Overall, there is no evidence that the aging of a pipeline system poses any greater level of spillage risk, the report says.
The development and use of new techniques, such as internal inspection with intelligence pigs, hold out the prospect that pipelines can continue reliable operations for the foreseeable future.
To read the full report, click here.
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