JEC COMPOSITES MAGAZINE - Issue #33 - June 2007 - 38

FEATURE Performance “Construction” g…/… Crescent city rebirth includes CIPP The resin was supplied in a liquid state that allowed the felt to be wet-out before the tube was inserted into the pipe. Because the Metropolitan Street force main does not have manholes, access pits needed to be excavated to accomplish the insertions. The Metropolitan Street project involved 1,420 metres of piping that was accessed through five pits strategically located to minimize surface disruption and facilitate insertion. Sections of supplied felt corresponded with the length of a planned insertion. The longest single insertion was 341 metres. A crane positioned the impregnated felt over the hole. Most CIPP liners are fabricated with isophthalic polyesters, a resin family with proven resistance to the chemical environment of municipal wastewater. However, the internal pressure of the New Orleans force main required Vipel® L010 bisphenol A epoxy vinyl ester to take advantage of the resin’s higher tensile properties. “One of the most important resin attributes for resisting the force main pressure is tensile elongation,” explained David JEC Composites Magazine / No33 June 2007 = 2 additional sources of information in the composite industry www.jeccomposites.com/magazine-subscription More information: www.aoc-resins.com 1 subscription form (FREE) Pinholes sealed, pipe strengthened Treadwell, CIPP resin product leader for AOC. “Using test method ASTM D638, a typical cast specimen of Vipel L010 vinyl ester exhibits a tensile elongation of 4.6%, compared to 3.0% for our Vipel L704 isopolyester.” To keep wastewater moving, the pressure in the Metropolitan Street force main generally operates in the 2.1 to 2.8 bar range. To ensure sufficient performance, the pipe with liner was designed to withstand an internal pressure of at least 4.5 bar. The felt was resin-impregnated by Boh Bros. workers inside a protective tent. The felt was then conveyed to a crane which lifted the tube over the hole for insertion. “The Vipel L010 vinyl ester offered good handling characteristics and processed very well in the field,” said Marlin Gonzales, Operations Manager for Boh Bros. “The AOC resin was provided through specialty distributor CIPPCON. As part of his great technical support, CIPPCON President Jim McCormick came out to observe the first inversion.” As the resin-impregnated felt was inserted into the access points, water was pumped into the tube. This created pressure that moved the felt forward and inverted it against the inner wall of the host pipe. At the end of each inversion cycle, the water was heated to initiate the chemical reaction that caused the resin to cure into a thermoset, crosslinked solid state. Finally, a new seamless liner was formed against the host pipe inner wall to seal off the pinholes and strengthen the pipe for efficient operation. The pipe rehabilitation included a minor system redesign to improve flow. Bends in the original system that were no longer necessary were removed and replaced with new ductile iron pipe. Application of the CIPP liner included these new pipe sections. Rebuilding the infrastructure is essential to bringing a sense of normalcy back to the residents of “The Crescent City.” While much of the activity is happening where all can readily see, essential underground sewer enhancement technologies are just as much a part of the post-Katrina rebirth.

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JEC COMPOSITES MAGAZINE - Issue #33 - June 2007

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #33 - June 2007