Identifying pipes and valves of high importance for efficient operation and maintenance of water distribution systems

Failure of a pipe or valve in a water distribution system causes service disruption and other inconveniences to the customers at or downstream of the failure location. To minimize the impact of such a pipe or valve failure, it is crucial to identify those pipes or valves whose failure will have the most severe consequences in degrading the performance of the system relative to that of other pipes or valves. In this paper, we develop two failure analysis methodologies, Pipe-by-Pipe and Valve-by-Valve, to prioritize the importance of pipes and valves in a water distribution system. The relative importance of individual pipes and valves is evaluated according to the number of customers who are forced out of service as a consequence of a pipe or valve failure. The methodologies are based on a segment-finding algorithm which defines a series of isolated pipes in the case of pipe or valve failure. A procedure based on the Breadth First Search is also developed to find sections of pipes that are unintentionally isolated in the isolation procedure for failed pipes. The number of unintentionally isolated customers is included in the Pipe-by-Pipe and Valve-by-Valve analyses in order to incorporate this negative effect of unintended isolation of pipes. The methodologies are applied to a case study of a water distribution system for which the most important pipe and valve are identified. The results are analyzed to form a guideline for improving the system reliability. The proposed methodologies were found to be a valuable tool for ensuring efficient operation and developing appropriate maintenance strategies, and thereby for improving the reliability of many water distribution systems.