However, an innovative use of fabric ductwork by Todd Gilroy, mechanical engineering department head at Capital Consultants, Lansing, Mich., eliminated under deck aluminum or PVC ductwork at the new $10.5 million Hastings Community Center addition to Hastings High School and saved local taxpayers more than $10,000.

The 24 to 42-inch-diameter Sedona polyester-blended fabric duct, manufactured by DuctSox, Dubuque, Iowa, also saved Hastings, Michigan taxpayers approximately thousands of dollars more in labor costs versus metal duct, according to Michael Vander Ark, project manager, River City Mechanical, Grand Rapids, Mich.

Gilroy continued the savings and fabric ductwork theme in the 8,500-square-foot gymnasium with 150 linear feet of 28-inch-diameter TufTex fabric duct and with 200 linear feet of 34 to 24-inch-diameter Sedona distributes 7,000-cfm of air conditioning in the high ceiling foyer.

Hanging systems for the duct vary per room. The gym duct was hung on a suspended cable threaded through the roof trusses that adds to the indestructibility that’s needed in a gymnasium situation. The natatorium’s top duct run and the foyer both use a conventional ceiling-hung H-track suspension system with radius sections to complement the complicated layout. For the unique drop section under the natatorium windows, Gilroy, Vander Ark and DuctSox engineers developed a one-of-a-kind “L-shaped” bracket system for suspending the low duct run’s stainless steel H-track under the windows that blends invisibly into the wall behind the fabric duct.

The 700-linear feet of H-track hanging system over/under the windows and another 100 feet across the 300-seat spectator area took approximately three days to install and would have gone up faster if it wasn’t the crew’s first experience in fabric duct suspension, according to Vander Ark. “Once the suspension system went up, it took only a few hours to string the fabric duct onto it,” said Vander Ark, who also oversaw the installation of the dehumidification and HVAC systems throughout the building. It was our first experience with fabric duct and it looks real slick in there…very high tech.”

Custom colored with school colors, the fabric duct also enhanced the 25-meter stretch pool’s fun, festive theme by architect, DesignWorks A/E, Grand Rapids, Mich. “Our first inclination in a natatorium is ductwork that blends in unobtrusively, but in this case the color, shape and placement adds to the aesthetics,” said Dennis Bekken, principal, DesignWorks A/E.

While the duct is visibly seen, it is barely heard. Gilroy’s promises of quietness to the school board held true with operating decibel levels of fabric duct that are below design standards.

Historically, fabric duct installation costs are always less than metal duct, however the two methodologies had been competitive in material costs. Since the project was completed, recent 40-percent steel material cost upturns have made metal duct costlier than fabric duct.

As school budgets continually get squeezed throughout the country, architects and consulting engineers will find ways to save new construction costs while still improving space conditions such as indoor air quality.