Survival Rate Analysis of Water Mains: a Comparison of Two Case Studies (Canada-Iran)

Ahmad Asnaarhi, E. McBean, B. Gharabaghi and R. Pourrajab


Frequent watermain failure is a major challenge for water utilities around the world. A quantitative picture of failure time, and the rate of failure for different types of watermains provide the opportunity for utilities to implement efficient proactive asset management strategies to minimize the overall cost of operations.

This presentation reports the the Kaplan Meier survival analysis for the time of failure in the watermains of two different case studies, one in Canada and one in Iran. Based on pipe material, the rate of survival is compared in metal and non-metal groups. In both data sets, cast iron pipes show fast deterioration relative to other types of pipe materials. Finally, the Cox regression model was considered to quantify the effect of independent variables on survival time. The results show that two independent variables namly Age and Number of pervious failures are significantly related to pipeline survival time.
From the engineering point of view, the result helps to develop rehabilitation scenarios based on a list of priority parameters.

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