Condition Assessment and Repair Prioritization of a Large Diameter Pipeline System

The Louisville Water Company (LWC) provides drinking water to almost one million customers in the Louisville Metro area and surrounding counties through a series of 4,200 miles of water mains. LWC has implemented an ongoing condition assessment program that includes the inspection, analysis, and repair of large diameter transmission mains and pipelines on treatment plant sites. Pipelines within the scope are a variety of materials including prestressed concrete cylinder pipe (PCCP), reinforced concrete cylinder pipe (RCCP), cast iron pipe (CIP), and steel pipe. The technologies used for pipe inspection varied for each material and consisted of electromagnetic, leak detection, acoustic wave-based stiffness testing, broadband electromagnetic inspection, low-frequency pulsed eddy current inspection, and closed-circuit television. A total of more than 96 miles of pipeline have been inspected between May 2009 and August 2018. Failure risk analysis of the pipelines narrowed the massive scope to particular areas for further inspection and specific pipes in need of repair. This paper reviews the types of inspection data obtained from each inspection technology, how the inspection data was used to evaluate the risk of failure for pipes of various materials, and how high-risk pipes were repaired. This paper will focus on the condition assessment program work performed in 2017 and 2018.