Composites featured in odor-control ductwork

ECS Environmental Solutions employs AOC's Vipel vinyl ester resin to filament wind more than 1,000 ft of fiberglass ductwork used in an odor-control system as part of a wastewater infrastructure project.

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AOC (Collierville, Tenn., USA) reported on April 9 that it has worked with ECS Environmental Solutions (Belton, Texas) to create an integral part of the city of Austin’s (Texas) complex wastewater infrastructure project. The new 3.9-mile/6.3-km wastewater tunnel increases capacity for the downtown district and facilitates residential and business growth in the area. An important part of the project is an odor control system.

ECS provided the odor control equipment and relied on AOC’s Vipel resin for more than 1,000 ft/305m of fiberglass ductwork and additional accessories. The ductwork ranges in size from 12 inches to 72 inches (305 mm to 1,829 mm) in diameter. Approximately half of the ductwork is buried below ground and had to be able to withstand thousands of pounds of high-density traffic driving over the site. Additional elements of the project include field joint kits, flexible connectors, control and back-draft dampers, bolt gaskets and two fiberglass exhaust fans rated at 40,000 cubic feet per minute (CFM).

ECS manufactured all of the fiberglass ductwork using a state-of-the-art computerized filament winder. The fiber was impregnated with AOC’s Vipel K022 corrosion-resistant vinyl ester resin, which is said to be ideally suited for filament winding. “The K022 resin was the best choice for this project,” says Jeff Jones, president of ECS. “Some of the gases in the air stream are corrosive – hydrogen sulfide and ammonia. There’s also sulfuric acid. Pipes built with this resin are very resistant to what goes in them: They will not easily corrode.”

To help ease installation, ECS prefabricated and sub-assembled the duct system at its facility, then shipped it to Austin about an hour away. A field crew of five from ECS traveled to the construction site and handled all the field layup.

“We work in a controlled environment in the shop, but in the field you are open to the elements,” says Jones. “Some of the days we were in Austin were cold and others were really hot. We had to adjust promotion levels and add inhibitors to work with the resin long enough to do a quality job under tough conditions.”

AOC’s Scott Lane, product leader, offered technical assistance that helped ECS re-formulate the resin. Eric Stuck, AOC sales representative, also assisted ECS in meeting the demands of this material-intensive project. “With the long runs and thick pipes, we went through material much faster than normal, and AOC was very good at meeting this fluctuation in demand,” says Jones.