TUESDAY, JUNE 20, 2017
A controversial liquid pipeline that runs under the Straits of Mackinac in Michigan has passed a series of pressure tests, according to its operator.
Enbridge Energy, which operates Line 5, announced Sunday that it had completed hydrotesting on both the east and west pipelines that make up Line 5 under the Straits. The pipeline, built in 1953, has been questioned recently by some citizens and environmental groups, who fear that the line is at risk for a failure.
1,200 PSI Test
According to Enbridge, the company tested the pipelines at 1200 psi, eight times the normal operating pressure of 150 psi, and declared them “fit for service.” The lines were both tested at 1200 psi when they were first built in 1953, the company says.
“We are pleased with the validating results of this very significant test of Line 5,” Enbridge said in a statement. “This test was one more in an ongoing inspection, maintenance and modernization regimen for our system.”
|
|
| Images: Enbridge Energy |
|
Enbridge's Line 5 carries oil and natural gas liquids under the Straits of Mackinac. |
According to the Associated Press, the tests were carried out in accordance with a settlement the company reached with the Department of Justice in the wake of two spills on Enbridge pipelines in 2010. One, on Enbridge’s Line 6B, spilled 843,444 gallons of oil in Calhoun County, Michigan, near the Kalamazoo River.
Enbridge said the successful test was “a credit to the unique and thoughtful design of Line 5—from the seamless, cored steel pipes, to splitting the line into two through the Straits, to the low operating pressure—the engineers of the Straits segment of Line 5 had a clear vision for building this vital piece of infrastructure to serve safely in the Straits, well into the future.”
Pipeline Critics
Critics have in recent months called for the shutdown of the line for fear that the 64-year-old pipeline could rupture, causing an environmental catastrophe in the Straits, which separates Michigan’s Upper and Lower Peninsula.
Earlier this year, Enbridge denied reports of coating holidays on the underwater stretch of the pipeline, admitting that an outer coating had some areas of delamination—but noting that the underlying coatings were intact, and in such a situation, repairs were not necessary.
 |
|
Critics worry that Line 5, shown here during a 2016 underwater inspection, could rupture, causing an environmental catastrophe. Enbridge notes that the pipeline has never had a leak. |
A report authored by retired engineer Edward Timm, published earlier this year by the National Wildlife Federation, questions the coating originally used on the pipeline, and posits that the pipeline “may be only one peak current event away from catastrophic failure.”
Enbridge has denied that there is any corrosion on the pipeline, and notes that in its 64-year service, the line has never had a leak.
Tagged categories: Coating inspection; Infrastructure; Pipelines; Program/Project Management
