Trenchless Technology

OCT 2018

Trenchless Technology is the premier communications vehicle for the trenchless industry. Through our multiple platforms, readers receive insights into the trenchless industry, as well as keep connected to the latest news, products and projects.

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32 T R E N C H L E S S T EC H N O LO GY O C TO B E R 2018 small open-cut segment to replace several critical valves. Based on a low analysis, PSE&G knew they had a tight window of time for this project before cold weather natural gas demands would require the 2,000 lf segment to be gassed-in. Challenges Faced, Challenges Met " We knew from our 30-in. experi- ence that we needed to beef up our vacuum capabilities and we created a Venturi system to improve suction.," Ragula says. " We also planned to in- ternally reinforce a portion of the line to bridge a 4-in. tap instead of a using full encirclement so we had the ability to line right a way." The tap was reinforced using a four- layer prefabricated patch of PipeMed- ic by QuakeWrap, a iber reinforced polymer (FRP) that PPM and PSE&G have used on previous CIPL projects. When the project was under way, crews faced four major challenges that their 30- in. experience did not prepare them for. Grit As with other CIP relining work, the host pipe needs to be as clean as pos- sible for the liner to adhere. PPM crews sandblasted the pipeline to an almost virgin white pipe to meet a NACE 2 vi- sual standard. To remove the grit, crews used several vacuum trucks combined with a Venturi system to optimize air low. Even with this modiied system, in segment two they found a long sec- tion of grit remaining. They tried sev- eral options to no avail. With input from its partners at Karl Weiss, PPM created a special pig that would be pulled through the segment, increasing the airlow velocity by nar- rowing the internal diameter of the pipe. This allowed crews to remove the grit with the vacuum equipment they had on the project. While this process took place, the team moved ahead with lining segments three and four. Liftoff and Chafing In its previous CIPL work, the in- version took place in the lining pit but due to the size of this liner with related equipment and the planned excavation pits, all of this had to take place above ground. This led to non- optimal entry angles for the liner into the host pipe. After the liner was cured in three of the segments, it was discovered that there was slight liner liftoff, also known as delamination, that occurred near where the liner entered the host pipe. After the discovery, repairs were made with epoxy and specially fab - ricated retention bands to hold the liner in place while curing . In segment one, and also due to the entry angles, the liner chafed and caused minor leaks due to the size of the 8-in. retention belt used to guide the liner into place. The leaks were fortunately outside of the pipe and in the remaining segments the retention belt switch to 4 in. and the lubrication was doubled resulting in no further chaing or leaks occurring . Major Tear Segment two, a 565-ft stretch, took 28 days to complete, irst , because this is the segment in which the afore- mentioned grit was stuck, and second, because, after three successfully com- pleted segments, the liner suffered a major tear when one of four tail bolts failed. Luckily for the team the three remaining bolts were still secure and they were immediately able to remove the liner over a 24-hour stint . Unfor- tunately, this happened as the colder late- October weather started rearing its head and the mandated November gas-in was fast approaching . " Lead time for liners is typically four to six weeks, but for larger lin- ers like this we can see up to 12 weeks because it is coming from Germany," Wickersham says. " Karl Weiss really jumped on board and worked around the clock to get the liner to us within two weeks and we were able to reline the section and get it done on time." After facing these in-ield challeng- es, Ragula says that on future large di- ameter projects – more 30-in. and pos- sibly a 42-in. is on the horizon – the team will opt for a longer excavation area for the lining pit to accommodate the larger inversion cone and trans- port hose from the pressure drum. Segment two was successfully in- stalled on Nov. 14, 2017, and a inal CCTV of the entire 2,000 lf pipeline took place Nov. 19. This record-break- ing renewed section of PSE&G's main- line was gassed-in on Nov. 20 just in time for the record-breaking cold win- ter that befell much of North America. "A lot of experience came together to make this project happen. It was very much a team effort between PSE&G, PPM and Karl Weiss," Ragula says. " The takeaway for all of this big stuff is that there are three things that you must do. Plan, plan and over plan and if you do those three things that can help you react to the unexpected that occurs, which almost always occurs in pipeline rehab and renewal work. It is just the nature of this business." Mike Kezdi is associate editor of Trenchless Technology. Project Owner: Public Service Electric & Gas (PSE&G) Engineer: George Ragula, PSE&G Contractor: Progressive Pipeline Management Manufacturers/Suppliers: Karl Weiss Technologies GmbH, ULC Robotics and QuakeWrap Value of Trenchless Project (US$): $6.2 million The Starline cured-in-place liner is guided from the truck to the inversion drum. The lining took place in four segments.

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