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Case Study ing. However, the resin was changed to epoxy because it was available domesti- cally. The method of curing the CIP was also changed to recirculating hot water to meet the performance specification of the product. Similarly, a pit was used to expose both storm and sanitary laterals, lateral lining, and install cleanouts during the lining procedure. Mainline grouting was completed in areas identified from the mainline dye- testing results. Grouting of interface was also completed between the sanitary lateral and the mainline sewer. Manhole sealing utilized a cementitious product with a flexible urethane product at the frame/wall interface. This product seemed to work the best in comparison with previ- ous products used. Testing that was implemented on this project included pre- and postflow monitoring, pre- and postdye testing, vacuum testing of the manholes, air testing from the cleanout to the mainline sewer, and physical testing of the CIP liner to verify strength parameters (flexural modulus and flexural strength). Lessons Learned Lessons learned during the Canterbury Area focused on complications due to the houses being septic tank conver- sions. Many had branch connections and could not be lined, and some liners had to stop short of the house due to a 4" diameter reducer at the interface of the lateral and the house. Some laterals failed due to workmanship. For example, resin was not cured properly, not measured correctly due to faulty equipment, calibration bladders pulled prior to curing, or installed too short. In some instances, the liner was installed too short from the pit to the main. Conclusions Throughout all four of the rehabilitation projects, lessons were learned in each one and at different phases of the proj- ect, from testing during the investigation, to bid and specifica- tion items, to product specification and testing, to construc- tion methods and installation. Key items for each segment of the project are discussed below. Testing techniques During the residential testing, locating the exact source or potential location of the leak will assist the engineering judgment of recommending lateral lining or spot repair at a specific house. Altering the testing procedures to spend more time searching for the leak on private property rather than discerning if it was positive or negative may possibly elimi- nate the lining and associated costs. Bid and specification items By conducting rehabilitation on several projects, the overall bid and specification document improved at each project. Important items that pro- tected both the city and the contractor were eventually included in the package. Specifically, number of cleanout pits, length of the lateral liners, how to deal with lateral branches, type of product, and quality assurance testing require- ments were all things that made important decision-making points at various times of construction during the project and provided insight for future improvements. It is important to include the proper testing procedures and requirements and hold the contractors and manufacturers to those requirements. Product recommendations While several products were used on these projects, overall success was based on the cumulative effort of the product, installation, and workmanship. Products that were successful were CIP liners, which were felt liners with an epoxy resin with hot-water curing. Chemical grouting was also successful on the mainline sewer joints; however, long-term exposure of the product has not been endured, as this was only installed within the last five years. Manhole liners worked much better with a flexible urethane grade ring than the rubber liners with straps. Construction methods One of the key lessons learned during these projects was the ability to find a contractor that has extensive experience in installing, testing, and overall knowledge of the product limitations. Throughout these projects, different contractors were used and each with varying degrees of knowledge and competence, which wasn't identified until the project was ongoing or had ended. With the advances in technology and new products being introduced to the market every year, it is important to find a contractor that has experience with a specific product. 40 Storm lateral compromised by roots wateronline.com ■ Water Online The Magazine Jim Smolik is an engineer and inspector for the City of Westlake since 2000. He is responsible for inspections and project management. Bob Kelly is director of engineering for the City of Westlake since 1992. He is responsible for 300 miles of sewers systems and has over 30 years in municipal sewer maintenance and design. Scott Belz is manager of field operations for URS in Cleveland and has over 35 years of experience in sewer collection systems.