Integrity digs prevent leaks to keep pipelines safe

When pipeline companies say, “safety is our top priority”, those words mean something. Pipeline operators back up that commitment with financial investment, ongoing measurement, and individual action.

For instance, in 2018 alone, operators invested $2 Billion to maintain and monitor their pipeline systems. They use sophisticated inline inspection tools (ILI), such as smart pigs, to identify even tiny flaws in pipelines. And, when inline inspection tools show there’s a significant flaw in the pipeline, operators conduct integrity digs. In those digs, they uncover the pipeline and use sophisticated technology to inspect it further, so they can decide on the best courses of action.

In this week’s blog, we’ll explore what’s involved in an integrity dig.

 

CEPA members conducted 2,665 integrity digs in 2018

 

Integrity digs are prevention measures that ensure defects in pipelines don’t become leaks. During an integrity dig, pipeline workers carefully remove the soil around the pipeline to get a closer look. This helps them determine if they need to repair or replace the segment of pipe.

In 2018, Canadian Energy Pipeline Association (CEPA) member companies conducted 2,665 integrity digs to examine pipelines for defects and make repairs. That amounts to a total of 29,425 integrity digs in the 10-year period since 2008.

 

The eight steps involved in an integrity dig

 

  1. The operator must first know the exact location for the proposed integrity dig and brief any affected landowners.
  2. The pipeline operator then inspects the pipeline right-of-way and uses the One-Call service to mark other underground utility services.
  3. Operators then expose the pipeline by carefully stripping the topsoil, followed by each of the next layers. They must preserve each layer so they can replace it in the same order. Although operators use machines to dig alongside the pipeline, the process to expose the pipe itself is done slowly and carefully, and done by hand.
  4. In environmentally sensitive areas, an independent environmental inspector is on-site during the entire integrity dig process to ensure the work does not adversely affect the land and environment.
  5. The next step involves finding the flaw. That entails removing the coating and cleaning the pipe surface to allow visual inspection. Flaws can be tiny and difficult to see with the naked eye, or they could be on the inside of the pipeline. That’s why operators use technology adapted from the medical field, such as ultrasound and X-ray, to help them locate and assess any flaws.
  6. Before repair and maintenance can begin on a pipeline segment, the operator must ensure the pipeline’s operating pressure is safe. Depending on the extent of the flaw, and if they determine the pipe section needs replacing, operators must carefully remove any product from that section.
  7. If the issue is external corrosion, a common repair method is to attach a reinforcement sleeve over the defective section to reinforce the pipe and keep the defect from growing further. Some reinforcement sleeves are steel, while others are made of composite materials like fibreglass and even carbon fibre.
  8. After they complete the repair, operators clean up the surrounding area, return the land to its original state, and keep landowners informed.

 

CEPA members transport the bulk of Canada’s daily natural gas and onshore crude oil to markets throughout North America. Safety is at the heart of the Canadian pipeline industry, that’s why operators monitor pipeline systems 24/7 and conduct integrity digs to ensure pipelines are safe.