Sooner, not later: A team approach to emergency preparedness in the Sooner State
Stories from the 2017 Enbridge Safety Report to the Community (Part 1 of 2)
Swift, vigorous response brings slope movement to a standstill
Published: June 19, 2018
Stories from the 2017 Enbridge Safety Report to the Community (Part 2 of 2)
The best way to respond to an incident is to stop it in its tracks.
In October 2017, the team working on an extension of Line 25, a 36-inch natural gas pipeline through the rolling countryside of eastern Ohio, did just that after encountering a problem—the hillside where crews had dug a trench to install the new pipeline was slipping downhill.
At first the signs were subtle, with soil sliding into the open excavation. But Bob Fisher, who was in charge of the construction, knew it could point to bigger problems.
Fisher consulted with Mike Lemaster, operations area supervisor, and a further investigation revealed that two existing natural gas pipelines in the same right-of-way, 25 and 50 feet uphill from the trench, were also moving.
Fisher and Lemaster shared these findings with their colleagues and management, kicking off a vigorous response—with Enbridge mobilizing a diverse team of experts from departments across the organization as focus shifted from construction of the new pipeline to protecting the existing lines.
The ground movement was comparatively slow, between one and five inches per hour, but every inch added more strain to Lines 10 and 15, two active 30-inch pipelines in the Texas Eastern Transmission system transporting natural gas from the Gulf Coast to the U.S. mid-Atlantic and northeast.
Fisher’s crews installed trench boxes in the open excavation in an attempt to stop the movement, but one day later, on Oct. 11, the hillside was still moving.
Swift, vigorous response brings slope movement to a standstill
Stories from the 2017 Enbridge Safety Report to the Community (Part 2 of 2)
“We’ll only operate our pipelines when we can confirm that they’re safe,” says Doug Dewar, one of Enbridge’s experts in managing geotechnical issues, who had arrived from British Columbia the night before. “With the continued movement and the strain that put on the pipelines, we had to act to avoid the potential for loss of containment.”
That meant shutting Lines 10 and 15 down so that crews could safely excavate them, confirm they were not damaged, and stabilize the hillside. To put that decision in perspective, the pipelines were transporting 1.8 billion cubic feet of natural gas a day.
“Shutting down the entire Texas Eastern 30-inch system is not an easy decision to make, but each layer of management and every department listened, asked questions, understood the gravity of the situation, and put safety first,” says Doug Barnes, one of Enbridge’s experts in pipeline integrity.
After crews excavated the soil uphill of the pipelines, relieved the strain and allowed the pipelines to rebound, Enbridge’s integrity team ensured the event hadn’t caused damage—inspecting the exposed pipelines, X-raying every weld, and bringing in one of the world’s leading experts on weld evaluation to assess the results and confirm that the joints were safe.
With the pipelines stabilized, Enbridge safely returned Line 15 and Line 10 to service three and four days, respectively, after they were shut down by our gas control center.
After that came a permanent solution—installing a retaining wall anchored into the bedrock, outfitting the pipelines with strain gauges, and establishing a survey grid.
“Shutting down those pipelines was a very big business decision—as big as it can get—with significant financial and operational implications,” says Barnes, “but Enbridge always puts safety first.”
