Air distribution at the pool level now relies on new returns at the shallow end to draw the conditioned air down from the supply duct.
Carlisle, Pa. - Paul Richards, aquatics director at Dickinson College, was certain that his pool suffered from "Sick Pool Syndrome."

Swim practice was periodically interrupted by team members with breathing problems caused by stagnant chloramines-laden air near the pool surface. Plus, 80 percent humidity levels had taken a toll on many parts of the 10,000-square-foot natatorium structure as well as the roof and metal amenities of the Kline Athletic Center, a connected 78,000-square-foot field house.

Ongoing roof problems in the adjacent field house that led school officials to appropriate $248,000 to remedy the situation with a complete retrofit for Dickinson's eight-lane, 25-yard-long pool natatorium.

Richards has a master's degree in sports sciences with a specialization in aquatics maintenance, management and design. For the project, he researched the latest natatorium technology with the help of Durwin Ellerman, supervisor of mechanical and electrical trades at Dickinson.

With the drafting and engineering help of Rich Munkittrick, vice president of manufacturer's representative H&H Sales, Mechanicsburg, Pa., Richards and Ellerman began designing a new system anchored around fabric duct by DuctSox¿, Dubuque, Iowa, and a heat recovery dehumidifier by Dectron Internationale, Roswell, Ga.

According to DuctSox, fabric duct air dispersion is becoming popular because the polyester-base material doesn't corrode or attract condensation in aquatic environments.

Like many natatoriums built in the 1980s, the 23-year-old pool was originally designed with only a commercial air conditioning unit that provided unsatisfactory cooling and no dehumidification.

The air distribution system was ineffective. It consisted of two 4-by-4-foot wall grille returns in one location and a series of five 3-by-1-foot wall diffusers located in only one wall. Air stratification was evident in more than 50 percent of the pool area. Air movement was particularly dead at the pool surface level where swimmers breathe.

Ideally, according to American Society of Heating, Refrigerating and Air-Conditioning Engineers, natatorium environments are most effective with a combination of under deck and overhead air supplies. Since under deck ductwork was not an economically feasible option at Dickson, the design team conceived of a main 52-inch diameter trunk line spanning 120 feet down the center of the natatorium. The trunk line consists of DuctSox's Sedona Comfort-Flow¿ model, which delivers about 15 percent of the airflow through the fabric's natural porosity. The remaining air is delivered through a linear diffuser and four 20-inch diameter perpendicular branches that spray the windows and the spectator section with 82¿F air.

The trunk line and branches were ordered in red and white, respectively, Dickinson's school colors. The trunk also sports the school logo that DuctSox silk-screened onto the fabric.