2017-06-15 / Front Page

Line 5 Tests Underway

By Erich T. Doerr


Enbridge Energy is conducting hydrostatic testing on its pipeline running under the Straits of Mackinac this month with the first test planned Saturday, June 10, and the second test planned for Friday, June 16. The white pipes pictured here are the Line 5 pipeline at its Mackinaw City pump station at the point where the two 20-inch lines that cross the Straits merge back together into a single 30-inch line. The hydrostatic test, the first on the line since one before it entered service in 1953, will involve pumping the line full of water and pressurizing it beyond its normal limits to test its strength. Enbridge Energy is conducting hydrostatic testing on its pipeline running under the Straits of Mackinac this month with the first test planned Saturday, June 10, and the second test planned for Friday, June 16. The white pipes pictured here are the Line 5 pipeline at its Mackinaw City pump station at the point where the two 20-inch lines that cross the Straits merge back together into a single 30-inch line. The hydrostatic test, the first on the line since one before it entered service in 1953, will involve pumping the line full of water and pressurizing it beyond its normal limits to test its strength. The Enbridge Energy Line 5 pipeline running beneath the Straits of Mackinac will undergo hydrostatic testing this week. The process will involve taking parts of Line 5 out of service, with the underwater section then being pumped full of water and pressurized well above its allowable operating pressures as a way to test light strength. The results of the test are expected to be available in mid-June, once both of the tests are completed.


Enbridge Regional Communications and Media Relations Supervisor Ryan Duffy talks about what the tests would entail, including removing all the oil from the pipeline before filling it with water to pressurize it. Enbridge Regional Communications and Media Relations Supervisor Ryan Duffy talks about what the tests would entail, including removing all the oil from the pipeline before filling it with water to pressurize it. The test was mandated as part of a settlement with the United States Department of Justice and the Environmental Protection Agency in relation to the company’s 2010 Line 6B spill in the Kalamazoo River.

This marks the line’s first hydrostatic test since the one conducted before it first entered service in 1953. The goal of the test is to determine if the underwater Straits section of the pipeline remains as strong as when it was installed more than six decades ago.

The St. Ignace News was invited by Enbridge to see the equipment it will use during the test Thursday, June 8, before the tests began. Preparation work at Enbridge pump stations in Moran Township and Mackinaw City began three weeks before the test period started.


Enbridge Energy Line 5 Operations Manager Blake Olson shows off the piles of white absorbent booms Thursday, June 8. Four trailers full of booms like this are kept in Mackinaw City and Moran Township at all times. The white booms pictured here would be placed alongside local shorelines to absorb oil if Line 5 ever had a spill. The company also has orange booms in each location that would be towed behind boats to collect oil from the water before it ever reached the shore. Enbridge Energy Line 5 Operations Manager Blake Olson shows off the piles of white absorbent booms Thursday, June 8. Four trailers full of booms like this are kept in Mackinaw City and Moran Township at all times. The white booms pictured here would be placed alongside local shorelines to absorb oil if Line 5 ever had a spill. The company also has orange booms in each location that would be towed behind boats to collect oil from the water before it ever reached the shore. “We’re committed to the safe transportation of energy in Michigan,” Enbridge Regional Communications and Media Relations Supervisor Ryan Duffy said. “This test is a visual representation that all of our maintenance [on Line 5] has been successful.”


This giant pump and temporary piping have been installed at Enbridge Energy’s Line 5 pump station in Moran Township to move water in and out of the pipeline for its current hydrostatic tests. The pump is pictured Thursday, June 8, alongside the giant 350,000-gallon tank Enbridge built at the site to store the water for the test. This giant pump and temporary piping have been installed at Enbridge Energy’s Line 5 pump station in Moran Township to move water in and out of the pipeline for its current hydrostatic tests. The pump is pictured Thursday, June 8, alongside the giant 350,000-gallon tank Enbridge built at the site to store the water for the test. The hydrostatic tests have been scheduled for Saturday, June 10, and Friday, June 16. Thursday, water was already in the line stabilizing it in advance of the first of the two tests. In most places, Line 5 is a single 30-inch diameter pipe, but at the Straits crossing, it splits into two 20-inch lines. The underwater lines will be tested one at a time.

The testing process will involve taking the underwater portion of Line 5 out of service, sealing it from the rest of the pipeline, and forcing the oil out of it. The pipeline will be filled with the inert gas nitrogen after all the oil is removed. The nitrogen will then be forced out and vented off in Mackinaw City as the pipeline is filled with water for the test. All of the gases will be scrubbed before release into the atmosphere.

Enbridge’s testing process is being overseen by several government agencies including the U.S. Pipeline and Hazardous Materials Safety Administration, the Environmental Protection Agency, the State of Michigan, and several independent third-party contractors that report to the EPA. Mr. Duffy said Enbridge would be collaborating with the State of Michigan to make the results of both hydrostatic tests available to the public once everything is completed.

The first test June 10 focused on the western side of Line 5, finding no issues. The June 16 test will test the eastern pipe.

Taking the line out of service means Enbridge will be moving 5% less oil downstate during testing. The test is not designed as a precursor to any increase in flow through the line. Enbridge increased the amount of material following through Line 5 by 10% in 2011, after retooling its pumps so no increases in pressure were necessary. Line 5 carries natural gas liquids during about 30% of its operation time and oil during the rest of it.

Once filled with water, the line will be pressurized up to 1,200 pounds per square inch (psi) to test the integrity of the line. This pressure is twice the 600 psi maximum level that Enbridge’s lease with the state allows it to operate on the line. Line 5 Operations Manager Blake Olson said Thursday the line is normally operated at a level of 120 psi and he could not recall any case when its operating pressure was ever taken above 300 psi. The Straits crossing of the pipeline is designed for operation at a low pressure. For comparison, he noted most garden hoses operate at 40 to 60 psi. The original hydrostatic test in 1953 just after the pipeline’s construction also took it up to 1,200 psi.

“We’re going to show [Line 5] is as good as the day it was built,” Mr. Olson said.

Line 5 test project Manager Matt Fournier said each of the two tests would last eight hours. Four hours will be the 1,200 psi strength test to show the line can handle twice its possible operating pressure. After that, the line will be bled down to 1.1 times its maximum pressure and left there for four hours to make sure no leaks come up. He said in the unlikely event a failure were to occur during the test, Enbridge would have to stop testing, fix the problem, then do the test again from the start.

Mr. Fournier said all pipelines are given a hydrostatic test before they first enter operation. Additional tests after the first are rare and only done if a pipeline operator is asked to do so or is looking to make an alteration on its line.

The hydrostatic test has required the construction of a 350,000-gallon, above-ground water tank on the Upper Peninsula side of the line. Almost all 350,000 gallons of water will be necessary for the test. The tank was assembled from seven interlocking panels and is 73 feet in diameter. It is insulated to prevent the water from heating up during the storage period. Two large pumps and a series of temporary pipes have also been installed to bring the water from the tank into the pipeline, then return it. The same water will be used for both tests with an onsite treatment area preparing it for the second one. Once the tests are completed, the treated water will be trucked offsite for safe disposal at the City of St. Ignace water treatment plant.

Thursday’s tour also included a discussion of the various pieces of safety and oil spill response equipment that Enbridge keeps in the Straits area in the event Line 5 did have an issue. Four trailers of booms for recovering oil from the lake and protecting the shoreline are kept on each side of the Straits, with the Current Buster, a system designed to recovery oil in fastflowing water, stored in Mackinaw City. There are two sizes of Current Busters, one for towing behind a large boat and one for Enbridge’s own smaller response boats.

Enbridge response boats are jetpowered and have no propellers, so they can be operated in shallow water and can be launched from almost anywhere, including the Lake Michigan shoreline next to the Mackinaw City pump station. Crews are always standing by to respond. A vacuum truck for retrieving collected oil from the water is stationed in Mackinaw City for transport by flat top freight ferry to a leak. Enbridge contracts with a local company for that purpose.

Enbridge runs several in-line inspection tools through Line 5 annually. Some of them are tools to measure the pipe’s roundness and in-wall thickness, while others focus on finding any problems from corrosion or microcracks.

When Line 5 is in operation, electronic flow meters measure how much material travels through the line. Oil and natural gas move through the line at a speed of about five miles per hour. Small crews rotate through several stations alongside the line to carry out general maintenance.

Divers, remote-operated vehicles, and an autonomous underwater vehicle are used to monitor the exterior of the line beneath the Straits. A team will be coming in August to carry out this inspection, install more supports along the bottom of the lake for it, and measure the thickness of the pipe. Studies so far have shown no damage to the line from mussels underwater, but Enbridge is continuing to monitor the situation.

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