Condition Assessment Technologies for Water Transmission and Distribution Systems (EPA/600/R-12/017) March 2012
As part of the U.S. Environmental Protection Agency's (EPA's) Aging Water Infrastructure Research Program, this research was conducted to identify and characterize the state of the technology for structural condition assessment of drinking water transmission and distribution systems. The broad definition of structural condition assessment of water mains encompasses physical modeling of the pipe in the soil, understanding of pipe failure modes, empirical/statistical modeling of historical failures, inspection of a pipe to discern distress indicators, interpretation of distress indicators into pipe condition rating and modeling deterioration to forecast future failures and pipe residual life.
Any asset management program must start with a thorough review of available historical data about pipe performance and failure. Once the necessary data is gathered, deterioration models can go a long way in providing insight into the condition of these assets. A well-defined and cost-effective inspection program that complements the historic data can then be used to fill in gaps that remain. This report provides a comprehensive inventory of both condition assessment technologies and decision support systems applied to water mains and identifies capability gaps that need to be addressed. A comprehensive list is provided of existing non-destructive evaluation technologies and techniques that are currently used for buried pipes or that have the potential of being adapted to pipe inspection. Scientific principles, advantages, and limitations of each technique are described. A review is also provided of physical models, statistical/empirical models, and decision support software tools available to facilitate water main renewal decisions.
To date, there has been a substantial amount of work and effort that has been invested in developing approaches and tools for the condition assessment of water mains. However, there are still a number of technology gaps and research needs including: the need for live internal insertion and retrieval of inspection tools; the need to assess joint condition in metallic pipes; the need to develop technologies for asbestos cement and plastic pipes with few options currently available; and the need for low cost inspection methods to conduct screening for high risk locations in all pipe types for further assessment. To overcome the barriers and challenges identified in this research, field demonstrations and further research efforts are warranted in order to test promising technologies that could fill these gaps against well defined performance criteria and to identify the critical performance, cost, and/or value added attributes of emerging and innovative technologies for water main inspection.
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