How do you know Line 5 is safe?
Our Answer
Inspection results along Enbridge’s Line 5 have regularly told us that from an engineering and maintenance perspective, the pipe is like new and in excellent condition.
Prevention is a critical component of pipeline safety, and we focus on prevention at Enbridge before issues arise. The Line 5 Straits of Mackinac crossing was built to extraordinary design and construction standards, and Enbridge has been vigilant in supporting those standards with prevention measures such as:
- proactive and robust maintenance
- operating the line at less than 25% of its maximum design capabilities, to minimize stress on the pipeline steel and enhance safety
- diligent, 24/7 monitoring of the crossing, using both specially trained staff and sophisticated computer monitoring systems
- regular inspections, using inline tools, expert divers, and remote operating vehicles (ROVs)
- Pursuing and advancing commercially available technology to prevent anchor strikes while we build the Great Lakes Tunnel to house Line 5 deep under the Straits
Additionally, in June 2017, we successfully completed two hydrostatic tests of the east and west pipelines that traverse the Straits. The segments were separately emptied of oil, filled with water and pressure tested to the same level as they were tested to prior to being placed in service in 1953—1,200 pounds per square inch (psi), which is far above the normal daily operating pressure of about 150 psi.
Passage of the pressure test also is 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 in 1953 for building this vital piece of infrastructure to serve safely in the Straits, well into the future.
In fact pipelines, including Enbridge’s Line 5, have an indefinite lifespan if they are properly operated, monitored and maintained. In 2013, then-U.S. National Transportation Safety Board (NTSB) chairwoman Deborah Hersman testified before the Senate Commerce Committee: “If (a pipeline) is adequately maintained and inspected, age is not an issue.”
