Trenchless Technology

JAN 2019

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Page 38 of 67

W W W.T R E N C H L E S S T EC H N O LO GY.C O M 39 line would have cost the city $500,000 at the least . With this trenchless op - tion and its BCIP funding , North Bay handled the bypass and excavation of the lining pits, providing a consider- able savings. Tomahawk in Action The Tomahawk System requires two vehicles — an abrasive and coating de- livery trailer and a positive displace- ment vacuum truck to provide the airstream — and a four-person crew to handle the work. Following the Toma- hawk Cleaning and inspection with the Tomahawk Scout CCTV camera, the same trailer and vacuum truck rigging is used to move the BluKote through the line. Any residual BluKote is col - lected in a material outlet and does not make its way into the vacuum truck. BluKote is an AWWA Class 1 non- structural liner that meets NSF/ANSI 61 certification for drinking water. The two -part resin is poured into the line at the trailer end and the vacuum truck sucks the resin, along with the Distrib - utive Body (DB), through the pipe. The DB is tethered to a winch in the trailer and helps distribute the BluKote even- ly throughout the line. Because the sys- tem uses the airstream, BluKote also fills pits and joints and evenly wraps around service connections. " We can line 100 mm, 150 mm and 200 mm lines, which make up about 75 per cent of the distribution pipes in North America," says Brian Thorogood, general manager, Envirologics. " The North Bay project also allowed us to test lining a longer stretch and lining in both directions." Because the pilot projects and lab tests were completed on shorter sec- tion of lines, Thorogood says that the North Bay project offered Envirologics and Logistique Saint-Laurent the op - portunity to test the length that can be lined. Preliminary tests indicate that 107 m of 150 mm diameter watermain can be lined without interruption. The team was able to line up to a 115 m stretch of a 135 m section. To cover the entire length the equipment was turned around and lined in the oppo - site direction. When looking at the video, Joseph says that you cannot see where the sec- tions meet . To line more than 115 m the crew will adjust the DB and modify the airflow and that was tested on the other BCIP projects. The team also lined through some abandoned valves with no problem and through PVC transitions where the watermain was repaired over time. They also found that all leaky services to the watermain must be repaired pri- or to application as any moisture in the watermain inhibits proper bonding . According to Joseph, the crew took all of this information learned and has used it on the subsequent BCIP lining projects in Huntsville, Ontario; and Sherbrooke, Saguenay and Alma, Que- bec. Mike Kezdi is associate editor of T renchless Technology .

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