The design challenge the Princeton Fitness & Wellness Center presented for Rick Piecara, HLM Design, and mechanical contractor, Desesa Engineering, was that three pools with three different temperatures and functions had to operate in one large natatorium.
The success of the 21st century medical trend combining hospital and health club services in one facility is as dependent on high-tech HVAC equipment as it is on medical and fitness technology.

The new 50,000-square-foot Princeton Fitness & Wellness Center, an affiliate of University Medical Center at Princeton (Princeton University, Princeton, N.J), is a model example.

Operating as a satellite of the medical center, the $8 million facility includes amenities such as a child-care center, occupational therapy, cardiac rehabilitation, strength training, aerobics, physical therapy, pulmonary rehab, community meetings, women's health services, administrative offices, a juice bar, and state-of-the-art fitness facilities.

It's the 8,000-square-foot natatorium however, that serves as one of the major focal points, according to Stephen D. Kay, managing partner, Fitness & Wellness Professional Services LLC, which owns and operates the facility with its joint venture partner, the medical center.

In Good Health

The natatorium is one of the key factors in creating unique synergy between fitness and health care, according to Rick Piecara, manager of engineering for the Philadelphia office of architecture and engineering firm HLM Design.

"The challenge to this unique natatorium design is to assure that medically-based wellness, therapy, and rehabilitation programs could be provided along with fitness center aquatic programs," said Piecara.

HLM Design's solution was three separate pools with individual water temperatures and functions in one large room to provide access for both rehabilitation patients and fitness club members. For clinical wellness, fitness training, and club competitive swimming programs, there's a 25-yard-long, five-lane lap pool.

The second pool is a 30- by 30- by 4-1/2-foot pool with both portable and in-pool hydraulic lift for individual and group health care therapy as well as club aerobics and aquatics classes. The third pool is a 15-foot diameter, 10-person whirlpool spa for both health care and club therapy.

The 85 degree F therapy pool and 104 degree F spa pool share their own 86 degree F air zone supplied by a RS-100 dehumidifier by Dectron Inc.

Meeting Varying Needs

While this diverse natatorium might be designed to offer facility users the best of all worlds, dehumidification design is critical because all three vessels have different evaporative rates and surrounding air space temperature needs.

Piecara designed the natatorium HVAC with a warm zone and cool zone supplied by two energy-recycling dehumidifiers by Dectron Internationale (Roswell, Ga.), which efficiently recycle energy to heat the pool and therapy pool water.

The dehumidifiers are completely separate from the rest of the building's HVAC system, which consists of direct expansion rooftop units by Carrier Corp. (Syracuse, N.Y.) and variable air volume boxes with terminal heating coils.

While controlling the entire building, a Carrier Comfort Works system only receives monitoring information from Dectron's proprietary Supervisaire® system which controls the zones in the natatorium.

"We always use a packaged mechanical dehumidifier for natatorium projects," said Piecara. "That allows us to control the in-door environment separately from the rest of the building, regardless of the outside air conditions."

The Dry-O-Tron® RS-150 controls the cooler zone of the lap pool to 55 percent relative humidity (rh) with 8,500 cfm of 84 degree F air while simultaneously heating the water to 80 degrees.

Meanwhile, the 6,500-cfm, RS-100 supplies 50 percent rh and an 86 degree space temperature over the warmer zone of the 85 degree therapy pool water and the 104 degree spa," said Piecara, whose firm has decades of experience designing natatoriums of various sizes.

Piecara's air distribution design called for round, single-wall, spiral, metal, epoxy-coated ductwork, ranging from 21 inches to 18 inches in diameter.

The cool zone has perimeter ductwork hanging 4 feet below the 19-foot-high ceiling, while the warm zone is a U-shaped design covering three sides of the spa and therapy pool area.

All ductwork is painted vibrant colors that coordinate with the HLM Design interior design department's color themes throughout the building.

"It wasn't necessary to add the extra cost of underdeck ductwork or deck radiant heating like we have in other buildings because there are few windows," Piecara said.

Also critical to the indoor air quality is the six minimum air changes per hour HLM designed into the natatorium. Piecara ordered Dectron's Smart Saverâ„¢ option, which efficiently recovers heat from exhaust air to aid the space heating.

The lap pool has its own zone and RS-150 dehumidifier by Dectron Inc., which maintains a space temperature of 84 degree F air and 80 degree water even though the therapy pool and spa are only a few yards away in the same room.

Pooling Together

While budgets and energy-saving functions are important, the owners' main concern was perfect indoor air comfort for members and medical center users, regardless of the season.

"We like the indoor air comfort of the natatorium, plus there's not a hint of pool chemical odors in other parts of the building," said Kay.

Assisting HLM in the design of the dehumidifier was David Moore, sales engineer, Sass, Moore & Associates (Woodbury, N.Y.), who suggested the unit come with a factory precharged integrated condenser and be prewired to ease installation and startup.

Additionally, Stephen Conti, vice president of mechanical contractor Desesa Engineering Co. (Livingston, N.J.) felt the refrigerant piping, which totalled 50 feet in the original remote condenser design, required too many connections that could lead to future leaks.

"We accomplished our goal of having perfect air and water temperatures from day one without a lot of startup refinements," Piecara said.

One reason for the project's engineering success, according to Piecara, is the fact that both architecture and engineering designs came from HLM Design.

Piecara was able to implement construction techniques that are vital for the HVAC success, such as vapor barriers, the absence of skylights, and planning a minimum 15 percent of wall area for natatorium outdoor windows to eliminate condensation concerns. He asserted that the synergy of the facility is a marketing manager's dream because the medical patients are exposed to the health club's advantages while the health club patrons might be drawn to medical services of the building.

Princeton marks the third facility Fitness & Wellness Professional Services has completed, and three more projects are on the drawing board that highlight the natatorium as a focal point.

"Combining health care with preventive wellness services in a single facility is the wave of the future," said Kay.

Publication date: 01/17/2005