Consideration of PACP Limitations for Prioritization of Gravity Sewer Improvements

摘要

Since 2002 the Pipeline Assessment Certification Program (PACP) has improved the assessment and prioritizationof gravity sewer assets to an objective standard that tracks system condition over time. With over 200 options fordescribing structural, operation & maintenance and construction observations, PACP has added codes to refineevaluation of pipe materials and conditions. It has also integrated an Asset Management protocol for criticality asConsequence of Failure (CoF) and Likelihood of Failure (LoF).The impetus for updating PACP observation codes is continuous improvement to provide value to the evolvingcondition assessment and rehabilitation industry. The future of the program (Version 8 and beyond) may be focusedon addressing limitations of observation codes to material types, application and piping size. This presentationprovides an overview of these issues; coding and scoring modifications by users made to massage condition ratingsto reflect system reality; and recommendations for addressing perceived short-comings of the observation codingand scoring system that has led to overly conservative assessments for certain pipe materials and sizes.A project example is highlighted supporting this thesis by illustrating the use of a criticality-based PACP modelfrom 2004 to present using PACP codes from various prescribed versions. The system example is based on a largerdiameter concrete gravity sanitary sewer that was rehabilitated based on PACP condition assessment prioritization.The project example presents analysis of CIPP post rehab including comparison of design decisions that would havebeen recommended if Version 7 codes and rehabilitation technology advancements were available.