Engineered Systems NEWSCase in Point

Fabric dunks metal in pool environment

Only six years after the city of Raleigh, NC, built the 39,000-sq-ft Pullen Aquatic Center, the rust flakes falling from stainless steel ceiling ducts caused the city to shut down the natatorium and made complete duct removal necessary. "Every morning we would have more flakes in the pool," recalls Teri Stroupe, the city's aquatics director. "It built up. We had to polish the pool and the deck frequently just to keep the tile from staining red."

Stroupe and her staff conducted the search for a better ducting system that would eliminate the problem. They considered replacing the duct with a new stainless steel system and they also considered using a plastic duct system. Additionally, they looked at coating the existing steel duct.

They selected the new Comfort Flow DuctSox (Dubuque, IA) fabric air dispersion system to replace the old network of ducts. Stroupe says the DuctSox system was about half the cost of the other options and because they were concerned about the potentially huge cost of tearing down the existing system, cost was the deciding factor.

Rust Never Sleeps

The porous polyester fabric construction of DuctSox is virtually unaffected by pool chemicals in the air, which corroded the original stainless steel. Even though a recreational pool doesn't seem like a chemically hazardous environment, it can be torturous to metal of all types. "We had to work on our railings constantly to keep the rust down," says Stroupe. "Maintenance was a big issue. We were spending a lot on labor and chemicals to keep the pool clean. In a chlorine environment, you need something resistant like the fabric of DuctSox."

Finding an effective solution was only half the battle for the Pullen staff. The larger challenge was enduring the difficult process of removing the old ductwork. A two-story network of scaffolds was needed to enclose most of the building's exposed ceiling before beginning the four-week process of cutting down and hauling out the rusted metal ducts. It took another week to refill, heat, and chemically treat the junior Olympic-sized lap pool. By contrast, the bulk of the DuctSox installation was completed in two days.

Blowing Away the Chills

Stroupe adds that the finished DuctSox system does a better job of handling the tricky climate control conditions inside the pool area. Aquatic centers need plenty of fresh air to offset the odor of pool chemicals, she explains, while at the same time maintaining a constant temperature of 80 degrees F.

"We've seen such a more even distribution of air," she says. "People don't seem to feel a 'breeze' as much, which means more comfort for a person with wet, exposed skin. With the old system we had a duct blowing out at the end and it was very noticeable. Now it's not as noticeable. Our customers are not chilled from the air blowing on them," she says, adding that the new duct system is "a piece of our operation that we don't have to worry about anymore."

Bret Pettit, regional sales manager for DuctSox, says his product slipped easily into the existing duct pattern for an easy installation. "We were lucky because the diameter of the DuctSox was so close to the existing ducts so it was a rather simple installation," Pettit says. The bright white DuctSox also interact well with ceiling skylights, creating a clean, bright appearance.

DuctSox's best feature of all, Stroupe adds, will come into play when the removable, washable fabric ducts are taken down and cleaned. "We won't even have to drain the pool," she says. "After what we've been through, that will be really nice."ES