2017-06-22 / Front Page

Line 5 Passes All Hydrostatic Tests

By Erich T. Doerr

The second half of the hydrostatic testing process on the underwater Straits of Mackinac crossing portion of the Enbridge Energy Line 5 pipeline went off without a hitch Friday, June 16, as the company successfully pressure tested its eastern pipe up to 1,200 pounds per square inch (psi) with no issues occurring. The test followed up on the successful test of the western pipe to the same pressure Saturday, June 10.

While there is some fluctuation, the normal operating daily operating pressure of the pipeline is usually about 150 psi. Enbridge released a statement after the test saying they are pleased with the “validating results of this very significant test of Line 5.”

“This test was one more in an ongoing inspection, maintenance and modernization regimen for our system,” Enbridge Regional Communications and Media Relations Supervisor Ryan Duffy said in a release. “Our job continues to be ensuring the safety and reliability of Line 5 through the Straits, as well as our entire system in every community through which it traverses.”

Line 5 is usually a single 30-inch pipeline, but splits into two 20-inch pipelines for the crossing of the Straits. The tests involved emptying the underwater pipeline of all oil and liquid natural gas content, then filling the line with water which was pressured up far beyond the levels Line 5 is operated at to test the strength of the pipeline. The hydrostatic test duplicated the 1,200-psi pressure test on the pipeline just after its construction in 1953 and before it entered service. Enbridge’s lease with the state does not allow the pipeline to be operated above 600 psi.

Mr. Duffy said the successful tests show that Line 5’s condition is just as good as when it was built, proving the success of the company’s continual efforts to maintain and repair it. Enbridge credited the unique design of Line 5’s Straits crossing using two low pressure, seamless cored steel pipes with helping it pass the tests. The company added its engineers had a clear vision when building the pipeline that will allow it to continue to serve safely and reliably well into the future.

The hydrostatic tests were carried out to fulfill a requirement from the United States Department of Justice and the Environmental Protection Agency as part of the company’s settlement in relation to its 2010 Line 6B oil spill in the Kalamazoo River. The EPA, the State of Michigan, the U.S. Pipeline and Hazardous Materials Safety Administration, and several independent third-party organizations reporting to the EPA oversaw the testing process. An Enbridge helicopter made on and off aerial patrol flights above the pipeline and its pump stations during the testing process to monitor both the work and the earlier setup process.

Line 5 was not taken completely out of service for the testing process. When the western side was shut off for the first test the eastern pipe remained in operation. The eastern pipe was then taken out of operation while the western one was reactivated during the period of the second test.

While the pressure tests are now completed Enbridge will continue to work on improving the safety of the pipeline. Mr. Duffy said the company’s next project will involve coming back later this year to install 22 new anchor supports to the underwater section of the line to hold it tighter in place at the bottom of the Straits. There is supposed to be no gaps of more than 75 feet between anchorages. Mr. Duffy said the installation of more supports is designed to be a proactive measure.

Meanwhile, a state advisory board continues to study the pipeline and awaits a contracted report on its safety.

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