Washington Suburban Sanitary Commission’s Forensic Program: Leveraging Data by Performing Material Evaluation on Failed Metallic Water Mains

Metallic pipe failures occur due to a variety of factors related to the pipe material and its environment. These factors can lead to pipes requiring replacement before the fulfillment of their life expectancy. However, with adequate information, better life expectancies can be determined, and additional site-specific measures can be implemented. Washington Suburban Sanitary Commission (WSSC Water) has developed a Forensics Program that collects, evaluates, and analyzes failure data from pipe samples to determine the cause of failure. The Program involves the collection of pipe and soil samples from various events such as pipe breaks, water main replacements, and water main rehabilitation projects. Once samples are collected, metallurgical and failure defect analyses are performed to understand the failure mode. Subsequently, the failure data is evaluated and organized to understand correlations between factors such as material type, pipe size, date of installation, operational conditions, and environmental factors to gain a comprehensive understanding of the root cause. The Forensics Program proactively identifies and projects trends to minimize future failures through improved design standards, material selection, construction practices, replacement, and rehabilitation. The failure investigation of cast and ductile iron pipes, which account for 85% of the WSSC Water distribution system, provides a more comprehensive understanding of the pipe failure mechanisms. This understanding provides valuable insight into material performance and supports the comprehensive framework for forensic analysis. Implementing the tailored and specific solutions will lead to more effective management of the WSSC Water distribution system while increasing service reliability and decreasing operational costs.