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Quality Assurance and Quality Control Practices for Rehabilitation of Sewer and Water Mains
Citation:
Kampbell, E., D. Downey, AND W. Condit. Quality Assurance and Quality Control Practices for Rehabilitation of Sewer and Water Mains. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-11/017, 2011.
Impact/Purpose:
To inform the public.
Description:
As part of the US Environmental Protection Agency (EPA)’s Aging Water Infrastructure Research Program, several areas of research are being pursued, including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of rehabilitation systems. The objectives of this research effort were to collect, analyze, and summarize information on the installation and QA/QC practices for the trenchless rehabilitation of sewer mains and water transmission mains. In addition, consideration was given to practices related to water service lines, sewer service laterals, force mains, siphons, sewer manholes, pumping stations, associated wet wells, and other appurtenances. This review was accomplished primarily by conducting interviews directly with rehabilitation technology vendors, design engineers, and water and wastewater utilities that have a track record of using trenchless rehabilitation technologies within their network. The report provides an overview of how QA/QC issues have been handled in North America for trenchless rehabilitation technologies. Section 1 provides an overall background on current and historical practices for inspection and QA/QC of trenchless rehabilitation projects, including definitions of key terminology. The issues discussed include qualification testing (done to confirm suitability for a particular application), design considerations for these often proprietary technologies, the impact that the technologies have on the traditional QA/QC model for engineering projects (i.e., construction observation roles), and the level of emphasis placed on the QA/QC of the completed works versus more traditional replacement or new construction techniques. In Section 2, the various trenchless technologies currently available in North America are introduced and recommended QA/QC practices are summarized based on consultation with the technology vendors. Each major type of technology (including those that are relatively new and/or just now emerging) are discussed from the vendor’s point of view including the QA/QC criteria that they consider important to the successful use of their technologies in wastewater collection and water distribution systems. Section 3 presents QA/QC practices from the perspective of the utilities and/or the owner’s engineering representative. In this section, the authors explore not only this perspective from a North American point of view, but also from a review of how these technologies are treated in the European Union. European Union standards have been written in a framework that seeks to address the technical requirements of a particular application. The European Union standards require the individual technologies to be type- tested for the suitability of the materials in service in that operating environment, to prove the suitability of their in-situ installation process, and to establish the requisite QA/QC for installers. This inclusive framework is quite different than the traditional North American model of materials and installation standards (e.g., American Society for Testing and Materials [ASTM] standards) that tend to be exclusive to particular technologies. Additionally, the European Union standards set a requirement for continued installation process verification testing (referred to as audit testing) to maintain the qualification for a particular technology’s suitability in an approved application. It would appear from their written approach that a great deal of emphasis is placed on a quality finished product; although it is known to often fall short of this ideal in actual practice. Section 4 addresses the question of how North American utilities use the QA/QC documentation and other as-built information obtained from their rehabilitation projects to bolster their condition assessment and asset management activities. Given the demands on their time and shortfalls in budget, it is difficult for many utilities to adequately carry out QA/QC programs to provide the up-to-date information that is vital to asset management. Recognizing the value of the as-built information to future system maintenance, utilities should plan to commit the necessary resources to this effort.