A Comparative Analysis on Sewer Structural Condition Grading Systems Using Four Sewer Condition Assessment Protocols

Pipeline condition assessment is a primary task in running an efficient urban asset management program because in the case of system failure, the consequences can be significant to both municipalities and users. Selecting a suitable assessment protocol is crucial for municipalities, since the rehabilitation plans and network prioritization are set based on the structural rating system introduced by the selected protocol. Currently, North American municipalities use different condition assessment protocols, some of which are internationally-accepted, while others are developed based on local needs. This thesis compares structural condition grading systems using four condition assessment protocols; National Association of Sewer Service Companies’ Pipeline Assessment Certification Program, the Fourth Edition of Water Research Centre’s Sewerage Rating Manual, and early and modified editions of the City of Edmonton’s condition assessment standard. The differences and similarities among the four protocols are identified by performing surveys on more than 20,000 of sample pipelines. As a result, accuracy of each protocol is also established and presented.