The Air in There
Jenks Trojan Aquatic Center in Jenks, Okla.
Lifeguard Lung and other respiratory ailments are plaguing swimmers at many of the nation's indoor pool facilities. However, a $19 million high school natatorium is drawing rave indoor air quality (IAQ) reviews with its innovative HVAC design.
The new 50,000-square-foot Jenks Trojan Aquatic Center (JTAC) in the small Tulsa suburb of Jenks, Okla., passed its first major IAQ test with flying colors when it hosted 626 swimmers, 80 coaches, 60 volunteers, 30 referees and more than 1,000 spectators at the Speedo Championship Series Central Zone Senior Sectionals. Similar major swim meets across the nation are frequently marred by poor breathing conditions brought on by chloramines not properly removed by the facility design and HVAC system. However, the JTAC and its 50-meter, 13,000-square-foot pool proved it's a new state-of-the-art role model of future natatorium designs and retrofits based on meet participant feedback.
The meet's USA Swimming referee and 2012 Central Zone Officials Chairman, Stephen Potter, surveyed 100 participants on JTAC's facility conditions and recorded a 3.9-rating (on a scale of 1 to 4) evaluation for IAQ. It was by far the highest recorded air quality rating in the past 10 major meets held in the seven-state region's premier venues. The 2008 National Championships in Minnesota were set back by swimmer breathing challenges, according to Potter, so the region's swimmers are already attuned to air quality conditions.
"Venues struggling with air quality should make a trip to Jenks to see their unique setup, and the facility should be strongly considered for the next available Central Zone or Sectional Championships," said Potter, a 45-year veteran of swimming competition.
"The success of this facility is really due to the foresight of the design team," added George Villarreal, JTAC's manager and a 20-year swimming industry veteran.
Led by Ben Ferem, Jenks Public Schools' district executive administrator, the design team included: consulting engineer firm SHW Group, Plano, Texas; architect, Mark Bragg, principal, KSQ Architects, Tulsa; pool consultant Richard Scott, AIA, principal, Aquatics Excellence, Austin, Texas; and two manufacturer representatives for Decatur, Ga.-based dehumidifier manufacturer, Seresco USA Inc.—Engineered Equipment Inc. (EEI), Tulsa, and Texas Air Systems, Irving, Texas.
JTAC can boast about its natatorium IAQ because of the specification of two custom-manufactured Seresco NE Series 64-ton energy recovery dehumidification systems combined with one of the first applications of a new chloramines source capture/exhaust system manufactured by Paddock Pool Equipment Inc., Rock Hill, S.C., a commercial pool equipment manufacturer.
The dehumidification units heat or cool the space to 82° F and dehumidify to 55 percent relative humidity (RH). The dehumidifiers' heat recovery capability also offers the district the opportunity to integrate free 80° F pool water heating in the future. Besides the IAQ benefit of maintaining tight RH and temperature tolerances, the units also save JTAC operating costs through energy efficiency. Installed by the project's mechanical contractor, Mechanical Air Systems Inc. (MASI), Broken Arrow, Okla., each 46,500-cfm unit recovers compressor heat for pool water heating. They also use energy-saving direct drive plenum fans with variable frequency drive control. On days with ideal outdoor conditions, the system also shifts into economizer mode for additional energy savings.
Indoor air comfort and system operation is streamlined with a proprietary factory-based 24/7 remote monitoring/control service that communicates with each unit's Command Center via the Internet. The connection to the dehumidifiers allows factory technicians or authorized service technicians to monitor and control more than 100 operating parameters, including real-time refrigerant pressures—an HVAC industry first. Unit operation, monitored daily by the factory, can detect operating trends or component failures that might affect the HVAC conditions in the natatorium. In the event of a performance alarm, the unit sends notifying e-mails to authorized Jenks employees. The vital statistics, and especially recorded trending information, give factory technicians enough details to help support local HVAC service technicians on any issue that arises.
Even in perfect environments of proper ventilation, temperature and RH, chlorine molecules attach to ammonia and other organics introduced by swimmers, resulting in a heavy, noxious gas that congregates at the pool water surface, causing respiratory irritation. Natatorium ventilation design strategies typically direct supply air toward the perimeter and down to breathing zones at the deck surface, but very little on the pool surface. The ventilation specification adds Paddock's new Evacuator, a chloramines source capture/exhaust plenum-type of device integrated into one width of the pool gutter system that draws and exhausts chloramines directly off the pool surface.
The exhaust air contribution from the chloramines source capture/exhaust system, must be factored into the building's overall negative pressurization, which is a critical design criteria in all natatoriums. While it can exhaust independently of the dehumidifiers, the project saved significant equipment costs because the chloramines source capture/exhaust system is ducted to fans in the dehumidifier units, which carefully monitor and control the entire building pressurization status via their Command Center microprocessors.
Equally important is positioning the chloramines source capture/exhaust system at the pool edge nearest the natatorium's return air grille, which helps draw chloramines toward the evacuation system. Pool builder KC Gunite Inc., Belton, Mo., installed the 174 x 75-foot pool, pool equipment, gutter system and the chloramines source capture/exhaust system.
Even though chloramines reduction will extend the facility's lifecycle longer than most indoor pools, KSQ Architects' design team still cautiously chose materials that withstand the hostile environments of natatoriums. The entire pool surface is tiled instead of plastered, for example. And many square feet of wall surface use porcelain wall coverings, that resist corrosion and coordinate with the pool tile texture.
SHW Group's ventilation design also maintains a comfortable environment in the 1,200-seat spectator section. The dehumidifiers condition the area for typical daily use, but in the event of heavily attended swim meets, the HVAC system also activates a conventional make-up air package unit that functions as a backup when temperature or carbon dioxide target levels can't be maintained during full occupancy.
Another integral part of the superior ventilation design is white Sedona-Xm premium textile HVAC duct, which has an antimicrobial agent built into the material to minimize the harboring of biological contaminants that commonly occur in natatorium metal ductwork. The main pool area has four runs of 54-inch-diameter duct each with two airflow devices for adjusting air distribution inside the duct. The linear array of vents span the entire length and ensure an even and gentle distribution. The factory-engineered Comfort-Flow air dispersion porosity allows a small percentage of air to flow through the fabric to eliminate dust buildup and condensation. The spectator area uses 42-inch-diameter duct from its dedicated HVAC system.
With a heavily attended meet such as the Speedo Championships, the JTAC proved it is a role model with a design that should be considered in all new and retrofitted natatoriums.
"The IAQ was the best I've ever seen at a major swimming competition; there were no signs of coughing, burning eyes and the environment was comfortable for swimmers and spectators alike," said Villarreal.
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