Criticality Ranking and Condition Assessment of PCCP

The goal of a pipeline condition assessment program is to identify individual distressed pipe pieces or distressed sections of the pipeline that have high risk of failure and to repair such pipes in order to maintain pipeline reliability at a desired level. Implementation of a pipeline condition assessment program requires prioritization of all pipelines in the system to determine which pipelines to focus on first, selection of appropriate inspection technologies, implementation of inspection technologies, and interpretation of the inspection results. The purpose of this paper is to present a desktop model for prioritizing pipelines for inspection based on their criticality, failure risk curves for evaluating sensitivity to wire breaks for PCCP for the purposes of selecting appropriate inspection technologies, and field inspections for validating and refining the desktop model. This paper also includes a case study of a Joint Water Commission (JWC) in Minnesota that operates approximately 14.5 miles of PCCP constructed between about 1955 and 1999. A portion of a 36 in. diameter PCCP line recently failed twice and was replaced in 2015. During 2016 the JWC performed a condition assessment and failure risk analysis of all of its PCCP lines. The analysis included a desktop study, in-situ testing, and visual and/or forensic analysis of portions of the PCCP replaced during routine street reconstruction in 2016.