The real sweat came from eliminating metal ductwork sweating. Specifying 38°F chilled water and 45°F supply air temperatures instead of more conventional temperatures of 47°F and 55°F, raised the risk of ductwork sweating, which is a monumental consideration in lieu of the many recent school closings nationwide due to mold, bacteria and mildew infiltration.

KSA’s John Kluber, P.E., vice president, and Donald Ware, P.E., chief engineer, searched for a solution to ductwork sweating because of the significant savings at stake. Averaged at $3/cfm, Kuber’s 100,000-cfm air distribution reduction idea would save $300,000 in equipment costs, not to mention the additional savings from smaller ductwork and operating downsized equipment if only the duct sweating potential was resolved.

Instead of offsetting the savings with the added expense of ductwork insulation, fabric duct was specified because it doesn’t need insulation and doesn’t attract condensation. Kluber specified DuctSox, Dubuque, Iowa, fabric ductwork in the high school’s cafeteria, field house, natatorium, and open architecture administrative offices. DuctSox’s Comfort-Flow® design, which incorporates a factory engineered porosity as per Kluber’s specifications, disperses a small percentage of airflow through the fabric to eliminate condensation. The remainder of the airflow is dispersed evenly through linear vents that running the entire length of the duct, thus eliminating hot spots or air stratification.

Using fabric duct had more benefits than just eliminating condensation concerns. Fabric duct, which is 90 percent lighter thus considerably easier to handle and install than metal, saved an additional $80,000 in labor/installation costs, according to Bill Beukema, president of construction operations of the project’s primary HVAC contractor, Amber Mechanical.

“We saw labor generally cut in half on rooms requiring fabric duct, versus installing metal duct,” Beukema said. “If metal duct requires a four-man crew, fabric duct required a two-man crew.”

The cafeteria’s expansive skylight design was possible partly due to the lightness and flexibility of the four 30-inch diameter, white fabric duct runs that hang arched and parallel to the room’s barrel-shaped ceiling contour.

The absence of protruding metal duct registers and the aesthetics of DuctSox Sedona material also added to the futuristic appearance of the state-of-the-art cafeteria design. “I’ve worked on hundreds of projects,” said Kluber, “and this is the first time I’ve seen architects get excited about ductwork.”

Fabric duct also eliminated possible problems with natatorium air distribution as well, such as using expensive aluminum or galvanized metal with special paint, periodic maintenance, insulation, and all the other considerations associated with pool environment ductwork, according to Kluber.

The field house was particularly challenging in air distribution because of its size, high ceiling, and a running track around its perimeter. Kluber designed a perimeter fabric duct distribution system above the running track’s inner edge, however each section has its own custom factory engineered orifices that vary in placement and diameter as to the needed air throw requirements.

While cost saving was the main impetus for fabric duct, the noticeable difference in airflow quality and aesthetics is a subliminal benefit. “Some people think fabric duct is that shiny, cheap-looking stuff you see in industrial applications, but today’s technology gives it a high-end, sophisticated look and the sleek linear vents provide a much more even airflow than metal duct and registers,” said Kluber.

Adds architect, Ed Skahan, vice president, KSA: “Finally, ductwork actually adds aesthetics to a space.”