Failure assessment model to prioritize pipe replacement in water utility asset management

The condition of a water distribution system has strong correlations with community health and economic development. However, studies indicate an urgent need to upgrade the nation's aging and deteriorating distribution systems if they are to continue to provide customers with reliable and safe water supplies. In response, water utilities are using various performance measurement initiatives including pipeline asset management. A key component of this process is condition assessment of each pipeline in order to identify failure-prone pipes and prioritize their renewal. However, the below ground location of pipes and lack of standard guidelines or tools make pipeline assessment and renewal decisions difficult.; In this research, a pipe failure assessment model was developed and tested to assist water utilities with their pipe renewal decisions. Having refined the model through the collaboration of utility professionals, the model contains several unique features that facilitate its use and responsiveness to the industry's needs. The model consists of several modules written in Visual Basic for Application within a Microsoft Excel platform. Rather than requiring extensive field data to determine the cause of breaks, the model's failure prediction module and Multicriteria Decision Analysis modules use pipe inventory and break data compiled from the utility's operation and maintenance records. Recognizing that pipe renewal decisions are also based on risk avoidance, the model contains a consequence module that allows the decision maker to compare "what-if" infrastructure investment scenarios.; The model was tested using pipe inventory and break history information contributed by Laramie (Wyoming) Water and Colorado Springs Utilities. Evaluations from the participating utilities indicated that the model's use of routine pipeline operation and maintenance records, combined with its consequence modeling features, addresses the data limitations and risk avoidance characteristics of the industry. The investigation illustrates the need for better inventory and break data since this data plays such an important role in the industry's buried infrastructure planning programs.