MARIE ROTTSCHAEFER | MECHANICAL
DONGHYUN RIM
METROPOLITAIN AQUATIC CENTER
WASHINGTON, D.C.
General Building Data
Building Name: Metropolitan Aquatic Center
Location: Washington, DC
Building Occupant Name: District of Colombia Department of Parks and Recreation
Occupancy Type: Recreation
Size: 49,450 SF
Number of Stories: 2 + Basement
Primary Project Team:
Architect: Hughes Group Architects
MEP Design: JVP Engineers, P.C.
Aquatic Design: Water Technology Inc.
Civil: Delon Hampton & Associates, Chartered
Landscape: Lewis Scully Gionet
Structural: Brandes & Cassagnol Engineers
General Contractor: Sigal Construction
Mechanical Contractor: Power Max, Inc.
Electrical Contractor: Total Electric, Inc.
Dates of Construction:
Start: June 25, 2008
Finish: May 15, 2009
Total Bid: $25,946,151
Overall Cost: $34,700,000
Project Delivery Method: Design-Bid-Build
Building Statistics - Part I
Architecture
Hughes Group Architects designed the new facility to reflect the architecture of the Metropolitan High School Campus, but included elements that would allow it to have a unique identity. The brick façade mimics its campus neighbors, while curved roof sets it apart. The new “state-of-the-art” facility features a 25-yard X 50-meter competition pool with diving boards, a wellness/leisure pool, an adult whirlpool, spectator seating, and locker rooms with family changing cabanas. Additionally the new facility also includes several administration areas and support areas.
The facility has an administration and building support core located in the North East corner of the floor plan. The main level of the core houses the lobby, reception, administration offices, and access to spectator seating. The main entrance located on the North façade, provides a means of egress to the street. An emergency exit stair is located on South East corner of the core plan, allows access to the street from the lower level. The main stair and elevator to the lower level is located behind the reception desk. The lower level of the core contains separate men’s and women’s locker rooms and family changing cabanas.
The competition pool occupies a majority of the building’s footprint, and the space rises two stories, with a final ceiling height of 42’-4”. Spectator seating is located around the perimeter 14’-0” above the pool surface. The wellness/leisure pool and adult whirlpool are positioned adjacent to the competition pool. The ceiling height is lower in the leisure areas, only rising to 34’-0”.
Building Enclosure
The building support core and natatorium both utilize the same type of roof construction and wall construction. The images below show the construction of the roof and the exterior walls. The Metropolitan Aquatic Center was designed with clearstory windows and large arched curtain wall windows in the main natatorium area. The curved roof extends past the clerestory windows to provide shading from direct sunlight in the summer months.
Roof Construction
Sustainability Features
In 2009, the Metropolitan Aquatic Center achieved a LEED Silver rating. During the demolition and construction phases, debris from the existing facility were recycled. The urban location of the facility was an advantage because it allows for access to mass transit and alternative transportation.
The interior design allowed for daylighting and natural ventilation. Operable light-arch and clerestory windows allow sunlight to illuminate areas of the building during the day. When outside air conditions are ideal, the windows are opened to allow for natural ventilation. Exhaust fans were installed to perpetuate the air flow. In addition recycled materials were used for interior finishes. The design team also made and effort to utilize water saving features and efficient electrical and mechanical systems. Such elements include condensing boilers and photovoltaic solar panels.
Other Building Information
Applicable codes
Zoning
The Metropolitan Aquatic Center is located in Washington, D.C. Zone District R-1-B. The following information was provided by the DC Zoning Handbook.
Wall Construction
Historical
There are no historical requirements or elements associated with the Metropolitan Aquatic Center.
Building Statistics - Part I
Construction
The Metropolitan Aquatic Center was constructed to replace an obsolete pool facility located on a public high school campus. The existing pool facility was completely demolished and a new facility was built from the ground up. Construction of the Metropolitan Aquatic Center began in June 2008 and reached completion in May 2009. The project delivery method for the facility was Design-Bid-Build, and the general contractor was Sigal Construction. The total cost of construction was $25.9 million
Lighting & Electrical
The primary electric service is provided by Pepco Power Company; Pepco provides 13.2 kV to the site and pad mounted transformer that converts the power to a 480Y/277V distribution system before entering the facility. The Metropolitan Aquatic Center requires both 480Y/277V and 208Y/120V voltage distribution systems. Where 208Y/120V voltage distribution is required, a three-phase, four-wire trapeze mounted dry type transformer is installed to step down the voltage. HVAC equipment, aquatic equipment, and light fixtures are typically powered by 480Y/277V voltage distribution systems, while receptacles and other miscellaneous equipment are powered by the 208Y/120V voltage distribution systems.
The Metropolitan Aquatic Center also utilizes 191 photovoltaic cells, which are located on the roof, to minimize grid power usage when possible. Inverters convert the solar power from direct current to alternating current and then connect to the building voltage distribution system. When emergency power is required, the facility will utilize power produced by an outdoor emergency diesel generator.
Fluorescent lamps and compact fluorescent lamps are the typical lamps used in the fixtures in the Metropolitan Aquatic Center. The natatorium, however, utilizes HID metal halides, and LEDs are used in some of the office spaces and reception areas as well for emergency egress signs.
Mechanical
The Metropolitan Aquatic Center uses packaged roof top units to condition and dehumidify the different spaces in the facility. Terminal units, ACU-1 and ACU-2, were required to serve rooms where conditions could not be maintained by the central systems alone. The functions of RTU-1, RTU-2, and RTU-5 are described in Figure 3 below. RTU-2 and RTU-5 have economizer cooling cycles which take advantage of free cooling when outside air enthalpy is ideal.
RTU-3, RTU-4A, and RTU-4B are specifically designed for enclosed swimming pool environmental control and energy recovery. The units are capable of controlling space temperature and relative humidity, pool water temperature, and ventilation. These systems give first priority to maintaining the natatorium space temperature and second priority to maintaining the pool water temperature. All remaining heat is then transferred to a condenser. Each unit is integrated with a pool water condenser that is capable of rejecting all of the heat recovered from the compressor and the evaporator. The pool water condensers are counter flow, tube-in-tube type. Condenser pool water heating is controlled by a refrigerant solenoid valve that directs hot refrigerant gas into the pool water condenser as a response from the control system.
The pool water temperature is primarily maintained by the boiler system. Three gas fired condensing boilers are enabled whenever the temperature of returning pool water falls below the set point. Hot water is then pumped to a heat exchanger, which heats the pool water to the set point temperature.
Structural
The structural system of the Metropolitan Aquatic Center is a combination of steel and reinforced concrete. The main super structure of the building support core consists of structural steel columns, beams, and flanges. Due to the different roof elevations, there are several different types of columns loading. Typical columns spanning basement to the high roof are W10X33. Typical columns that support the RTU Roof are W8x48. Interior and exterior beams in the building support core have a 20 foot beam span. Interior beams are typically W12x19, while exterior beams are typically W12x14. Due to the unique footprint of the building support core, girders vary in size. Slab on grade is 3,000 PSI cast-in-place concrete slab with a depth 10 ½ inches. Elevated floors are 5 ½ inch light-weight concrete on 20 gauge metal deck.
Because the natatorium is a completely open space, there are almost no interior columns in this section of the building. The spectator seating and balcony are an exception; these areas are supported by 22” diameter concrete columns with # 10 rebar and # 3 ties. The natatorium roof is comprised of several different prefabricated steel trusses. All structural steel in the natatorium area is required to receive a high performance coating.
Fire Protection
The active fire alarm systems in the Metropolitan Aquatic Center include a fire alarm system, sprinkler system, and duct-type smoke detectors which notify the rooftop units to turn off when smoke is detected in the ductwork. Wall and roof construction fire-ratings were defined by code. All stair towers are enclosed with a 2 hour fire rated wall.
Aquatic Design
The Metropolitan Aquatic Center has three different aquatic systems: a25-yard X 50-meter competition pool with diving boards, a wellness/leisure pool, and an adult whirlpool. In order to create a healthy and creative environment, the pool water must be filtered and treated. Larger particles are filtered out through a filtration pump. The pool water is then disinfected with ultraviolet light and treated with acid and chlorine. Activity pumps keep the water flowing through the filtration systems. Each pool is closed loop and has its own filtration system, which prevents contaminants from one pool system spreading to all pool systems.
