Editor's note: The following is the unaltered statement that BP Alaska spokesman Steve Rinehart sent to Alaska Dispatch in response to a report written by ProPublica concerning North Slope pipeline corrosion, you can read that report, here.
The ProPublica piece about our North Slope facilities is missing some key information, and as a result presents an inaccurate picture of our pipelines and our active and successful program to combat corrosion.
We manage about 1,600 miles of pipeline on the North Slope. We do not have any "F-ranked pipelines." We do have 61 pipelines with specific identified local sites where corrosion or other damage gets an F-rank.
An F-ranking does not necessarily mean an unsafe condition or imminent failure. It does prompt a higher-priority repair plan depending on technical details and engineering review. The result can be immediate action -- a repair, a reduction in allowable operating pressure, or removing the line from service -- or a longer-term response.
In any case, strict safety criteria must be met. We will not operate facilities we believe to be unsafe. No line is operating out of industry standards or code. To our knowledge, we've never had a line with a F-rank defect fail in service.
There are currently 151 of these "F-rank" locations. The number fluctuates as new sites are identified and previous ones are addressed. What matters more than the number of points is the quality of the program, the tracking and the response.
Through systematic and continuing inspections (more than 150,000 external surface inspections and over 77,000 internal surface inspection so far this year), we identify and track specific locations where we have found corrosion or other damage. Based on the type of pipe and the degree of damage, we assign a letter ranking (A through F) to that location -- not to the pipeline itself.
It is not correct to say that the F-ranks (or the A thru Es) are all the result of corrosion.
Ranking can be the result of corrosion (typically, rust on the pipe exterior), mechanical damage such as nicks or dents, or a specific design or circumstance. Pipes are designed with much thicker walls than needed, to account for damage over time.
It is correct that a corrosion site with more than 80 percent of the pipe wall lost is assigned an F-rank. It is not correct to say all the F-ranks have 80 percent wall loss and could rupture.
For instance, a site can be ranked F if there has been comparatively little wall loss but the pipeline operates at high pressure. In such cases, the maximum allowable pressure is reduced to stay well within safety margins.
That's what we did to address the F-ranked sites found on injection lines at the North Gas Injection pad, while we develop a long-term solution. Those pipes are safe.
Here is the operating status of the 151 "F" rank locations as of Nov. 3:
We have an aggressive and comprehensive pipeline inspection and maintenance program. We systematically detect, track and mitigate corrosion damage. The response to inspection findings is based on what is necessary to ensure safe operations.