Antiquated Sewers Get Modern Makeover in Des Moines
March, 2006 : Nashville, TN
Nineteenth Century sewers under the City of Des Moines have been brought into the Twenty-First Century with new thermoset composite liners installed by Visu-Sewer Clean & Seal, Inc.
To ensure minimal disruption to the bustling Iowa state capital, Visu-Sewer used cured-in-place pipe (CIPP) technology. To ensure long-term durability, the new liners are made with Vipel® L704-FAH resin, a proven high molecular weight isophthalic polyester engineered by AOC for CIPP use.
The new project rehabilitated more than 12,000 feet (3650 meters) of brick sewer lines ranging in diameter from 18 to 60 inches (46 to 152 centimeters). Most of the original combined storm and sanitary sewer lines is estimated to be 80 to 100 years old, and several sections under the downtown district were most likely installed in late 1800s.
“The brick itself has performed well,” comments City of Des Moines Project Engineer Jeff Hansen, “but the mortar is failing the test of time. To repair the sewers, we chose CIPP over ‘sliplining’ a thermoplastic liner inside the old pipe. Compared to CIPP, sliplining would have left us with less flow capacity and would have caused significantly more surface disruption.”
Hansen adds: “With sliplining, we would need to dig more openings to be able to install the liner through the many curves in the system. With CIPP, Visu-Sewer was able to install most of the new liner through existing manholes. We’ve used Visu-Sewer for CIPP projects before. They do very good work.”
Resin-saturated felt
Visu-Sewer uses National Liner® CIPP technology licensed from National EnviroTech Group, LLC, Houston, Texas. National Liner technology calls for saturating a non-woven polyester felt liner with a corrosion-resistant thermoset resin, then inserting the liner into the pipe in need of repair. Under pressure, the felt liner is expanded against the interior of the host pipe. Under heat, the liquid resin cures into a crosslinked solid that encapsulates the felt to produce a new smooth, continuous liner inside the old pipe.
- Visu-Sewer resolved several design and process issues that arose during the Des Moines project. Drawing on their experience and expertise, Visu-Sewer workers knew how to:
- negotiate the resin-saturated liner through sweeping bends in sections of 36-, 42- and 48-inch (91-, 107- and 122-centimeter) diameter sewers;
- keep the resin from prematurely curing when temperatures in Des Moines approached 100° Fahrenheit (38 Celsius);
- install sections of liner where the grade changed as much as 15 feet (4.6 meters), and
- make adaptations when what was supposed to be 36-inch (91-centimeter) round cross-sections often ended up being 33-inch wide by 40-inch tall (84- by 102-centimeter) ovals.
Vipel® processability and performance
Visu-Sewer Project Engineer Alex Rossebo Visu-Sewer says that crews benefited from the good processing characteristics of Vipel L704-FAH resin. “Wet-out with the Vipel resin was never an issue, regardless of location” he states. “Wet-out of liners up to 48 inches (122 centimeters) were performed at our facility in Pewaukee, Wisconsin. For the 60-inch (152 centimeter) liners, three over-the-hole wet-outs were performed on site next to the Des Moines River. The longest over-the-hole insertion was approximately 1000 feet (305 meters).”
In addition to providing good processability, the Vipel resin contributes to City of Des Moines requirements for long-term durability. Rossebo says the resin retains a high modulus of elasticity over time while providing excellent resistance to the corrosive environment of municipal wastewater.
Visu-Sewer purchases Vipel resin through distributor CIPPCON, Inc. “We get terrific technical support from CIPPCON people,” says Rossebo. “They are available 24/7 when needed and are extremely flexible in scheduling resin deliveries for on-site wet-outs. A CIPPCON representative was there for our first on-site wet-out.”
Emilio Oramas, AOC business manager for Vipel corrosion-resistant resins, points out, “AOC helped pioneer the development of isophthalic polyester resin technology that sets the standard for most CIPP rehabilitation projects around the world. We’re pleased that this technology could give the people of Des Moines get a major infrastructure upgrade with little disruption to their daily lives.”
About Visu-Sewer
From headquarters in Pewaukee, Wisconsin, and branches in Fridley, Minnesota, and Bridgeview, Illinois, Visu-Sewer Clean & Seal, Inc., offers a wide range of services for sewer inspection, maintenance and rehabilitation throughout the Midwest. Visu-Sewer also provides complete, professional contract management to ensure that a customer’s sewer system is always operating at peak efficiency. For more information, phone (800) 876-8478, e-mail visu-info@visu-sewer.com or go to www.visu-sewer.com.
About National Liner
The National Liner® product is a proven, cost-effective trenchless pipeline rehabilitation system based on cured-in-place pipe (CIPP) technology. The product is made by saturating a non-woven polyester felt material with a high performance, corrosion-resistant thermoset resin. For more information, contact Ray Pavlic of National EnviroTech Group, LLC, in Houston, Texas. Phone: 800-547-1235; e-mail info@nationalliner.com; web site www.nationalliner.com.
About AOC
Headquartered in Collierville, Tennessee, AOC is a leading global supplier of resins, gel coats, colorants, additives and synergistic systems for composites and cast polymers. AOC is the North American leader in resins for corrosion-resistant applications such as CIPP. AOC products are manufactured in facilities strategically located in North America, Europe and Asia. AOC-owned manufacturing plants are ISO 9001:2000-certified, use proprietary technology to ensure resin batch-to-batch consistency, and follow Six Sigma-Lean principles for improved efficiency and quality.
CIPP is a priority at AOC. For more information on AOC materials, services and commitment to CIPP industry growth, contact Ben Bogner by e-mailing bbogner@aoc-resins.com or phoning (630) 665-2675.