Inspecting Large Diameter Pipes

Using Robotic Crawlers, Confined Space Entry to Make Accurate and Timely Asset Management Decisions

Trillions of gallons of water flow through our underground pipelines each year; transporting our wastewater, stormwater, and drinking water to benefit the human population. These pipelines are silent partners in our society. They operate for decades without failure and little maintenance. But even the most reliable partners get worn out from the effects of time and duty. Therefore, they require our help to restore their strength and longevity.

This article presents some of the more unusual defects that we have observed in large diameter pipelines. First, examples from robotic CCTV inspections will be presented. Then, we will explore the measurable data and failure analysis that we can ascertain from confined space entry pipe walk inspections.

Pipeline inspections are the important first step before any asset management decisions can be made. Furthermore, regular inspections allow us to monitor conditions over time. They also provide the data we need to determine when a pipe needs cleaning or rehabilitation.

NASSCO’s Pipeline Assessment Certification Program (PACP) is the national standard for the coding of defects inside of our sewer, storm, and water pipelines. NASSCO provides recommendations for the robotic equipment and field techniques to be used, as well as a library of defect codes that document construction features like manholes and taps. In addition, it documents structural and O&M Defects. Training in PACP ensures certified individuals can tell the difference between such things as: a crack and a fracture, the types of infiltration and deposits, and the various stages of surface damage.

NASSCO.org has an excellent PACP overview video which explains the coding system. All pipeline professionals are encouraged to obtain PACP certification.

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