Economics of Inspection and Condition Assessment of High-Consequence Water Pipeline and Assessing Its Remaining Life: Theoretical Framework

Abstract

This paper describes an approach enabling well-supported, rational decisions about when to deploy inspection and condition assessment for high-consequence water pipelines, which techniques and technologies to select, and when to stop assessing pipeline condition and plan for replacement. The proposed probabilistic approach considers the entire life-cycle cost of the pipeline, accounting for deterioration rate, failure consequences, cost of rehabilitation, accuracy and cost of inspection/condition assessment, cost of emergency repair versus planned intervention, and cost of total pipeline replacement. The approach allows combining expert opinion (semi-informative assessment) with hard field data (historical failures, and inspection and condition assessment results) into a robust, well-informed, and reproducible assessment of pipeline deterioration rate. The approach also allows pipeline owners to incorporate new field data, which in turns permits continually updating the assessment of the pipeline condition. The approach also estimates the remaining life of the pipeline, in anticipation of its complete replacement. End-of-life is defined as the time at which it is no longer economical to continue repair or rehabilitation, and full replacement is economically preferable.