Every day thousands of children blissfully swim and splash in Goldfish Swim School's 30-plus indoor pool locations nationwide, but what the participants and their parents don't notice is the perfect indoor air quality (IAQ) and air comfort that has been painstakingly built into each location.
IAQ is typically unnoticeable. However indoor pool moisture damage and its aftereffects can potentially create stealthy conditions that can compromise fun and educational swimming experiences, according to Steve Marszalek, construction advisor at construction management firm, Mosher Dolan, Royal Oak, Mich., Goldfish's nationwide contractor for build-out supervision.
Indoor air comfort is noticeable however, but little can be done once an indoor pool space is built and underperforms in either humidity or temperature control.
Since 90 percent of Goldfish franchisees economically locate their businesses in existing buildings, such as vacant industrial or warehouse buildings and retail shopping centers, envelope build-outs and humidity control are essential to success. The tendency for outward moisture migration during winter and inward during summer months creates construction challenges for any space not originally built for an indoor pool's humidity, vapor pressures and temperature.
To ensure every Goldfish location's success, Mosher Dolan employs a design team consisting of consulting engineering firm, Mechanical Electrical Engineering Consultants (MEEC) PC, Plymouth, Mich.; Krieger Klatt Architects, Royal Oak; and ThermalNetics, Auburn Hills, Mich., a manufacturer's representative for indoor pool dehumidifier and HVAC equipment manufacturer, Seresco USA, Decatur, Ga.
The design team typically thinks "outside the box" to proactively avert potential indoor environment problems when overseeing the build out of existing spaces for Goldfish franchisees. For example, traditional construction industry methodology recommends building out a structure's exterior wall with insulation and facades. However, Mosher Dolan contrarily builds steel-stud walls inward for Goldfish natatorium construction. The interior wall is built inward 10 to 12 inches to allow for an air buffer zone, insulation and a vapor barrier, which seamlessly envelopes the walls, ceiling and floor.
"The more a building is constructed outward, the more issues arise with structural steel integrity, masonry loads and air infiltration opportunities," said Marszalek, whose firm worked with Dow Chemical's Building Solutions division to develop a building format that combines construction and insulation materials that withstand the rigors of pool environments. "Mechanical dehumidification equipment is essential to humidity control in spaces like indoor pools, but the building's construction materials and techniques are equally important."
From the indoor air quality and indoor air comfort perspective, MEEC specifies a 10- or 12-ton NE-Series dehumidifier by Seresco USA. The units heat, cool and dehumidify the Goldfish spaces to 92°F and 55 percent relative humidity, respectively, while also using heat recovery to efficiently provide free 90°F pool water heating.
"The space and water temperatures, which are about 10 degrees higher than more conventional indoor pool rooms, makes the building envelope and dehumidification extremely critical for success," said William Vernier III, P.E., LEED AP, senior engineer, MEEC, which has designed HVAC for approximately 10 natatoriums consisting of community centers and hotels.
ThermalNetics typically sizes the dehumidifier based on the 25-by-75-foot pool's pounds of moisture/hour removal requirement to maintain 55-RH. Dehumidifier sizing also depends on MEEC's requested hourly four-to six volumetric air changes as per ASHRAE Standard 62.1, which complements Mosher Dolan's other IAQ efforts.
"Many equipment suppliers tend to calculate cfm as per wet deck area, which is typically two to four-feet-wide around the pool surface perimeter," said Vernier. "Our calculations follow the ASHRAE code, which requires 0.48-cfm/ft2 for deck and pool area."
As a backup, MEEC also specifies an in-duct heater by Markel, Gray, Tenn., on the outdoor air intake when outdoor ambient air temperatures fall below 35°F. A Lochinvar, Lebanon, Tenn., 260-Mb/h gas-fired condensing boiler heats mixed air and make up air to a discharge temperature of 100°F. Without the auxiliary heat, which is supplied through a Seresco auxiliary backup hot water coil, winter discharge temperatures and the large amount of required outdoor air can drop discharge temperature as low as 55°F. A second Lochinvar 400-Mbh boiler is used for fast pool water heating required after pool maintenance dump-and-fills.
Pool support equipment includes sand filters by Pentair, Sanford, N.C., and chlorine generators by ChlorKing, Norcross, Ga. Conventional high-efficiency HVAC rooftop systems manufactured by either Trane, Tyler, Texas; Carrier, Syracuse, N.Y., or Lennox, Richardson, Texas; condition the separate offices, reception, changing room and other dry areas.
To maintain perfect environmental control, each location uses proprietary web-based, automated remote monitoring program that allows a factory technician, building owner, HVAC contractor or other authorized personnel to access the unit's onboard microprocessor via a computer or smartphone web browser. Using real-time data along with historical recording and alarm features, Goldfish's technical staff can easily monitor dehumidifiers for optimum operational conditions, efficiency and ensure long-term energy savings and indoor air comfort versus conventional dehumidifier systems. Paul Mancini, sales engineer, ThermalNetics, also reviews data and alarms on all Goldfish Seresco units when events occur.
"There's no other remote control/monitor system like this available that's integrated into the dehumidifier operation and supported by the factory if local service people need to work on it," said Marszalek.
For example, at the newest location in 176,000-square-foot Boulder Run Shopping Center, Wykoff, N.J., Goldfish franchisee Timothy Casper's manager has a Certified Pool Operator's certification as well as WebSentry training to ensure the facility's mechanical equipment operates optimally. The 10,400-square-foot storefront features a four-foot constant depth gunite pool.
Pool builder Premier Pool Renovations, Plymouth Meeting, Pa., had a 12-by-16-foot hole cut in the back wall for truck and equipment access for excavating the floor. Like all Goldfish build-outs, the former retail space is outfitted with an inner wall, insulation, vapor barriers and other methods to prevent humidity and pool chemical air ex-filtration into the neighboring Mexican restaurant and Marshalls anchor store.
Installed by mechanical contractor, Comfort Control Systems, Haskell, N.J., the dehumidifier's coils are dipped in a corrosion-resistant coating and the refrigeration circuit uses pressure transducers for optimum compressor operation. Mosher Dolan also recommends franchisees take advantage of occupied and unoccupied modes the dehumidifier offers from its microprocessor for additional operation savings.
Goldfish's paradigm for space humidity and temperature control will help supplement its ambitious future expansion plans that depend on combining fun and swimming in an environment that is both healthy and comfortable for the patrons.