Jury: “[It is] one of a handful of buildings that is visibly, discernibly coming from a climate perspective that you can see. … The performance actually exceeds what would have been expected just looking at the project. That means there is a lot of craft in a lot of the details to actually push the performance. This project was not only an attempt to revitalize, but give the community a significant identity that reflects their values.”
Architect: “I was most excited about creating an urban solution in a suburban community. We wanted to bring people downtown and catalyze growth to discourage the sprawl in the greenfield areas, which is typical here. Now, people can walk through city hall’s courtyard, go under the breezeway and find themselves in the historic square where there are restaurants, a hotel, and a gallery.” —Mark Roddy, AIA, principal, design director at SmithGroupJJR
Ten years ago, the City of Chandler made a commitment to building its own facility after having leased space in various structures for a number of years. To do this, the city began saving portions of development fees from projects built within city limits rather than borrow money for construction.
The new City Hall in Chandler, Ariz., consists of low to mid-rise buildings on two city blocks, with the north block housing a five-story office tower and several one-story buildings, and the south block housing one-story buildings and a two-level parking structure. SmithGroupJJR had three underlying goals for the project: to provide an identity for the community, to bring together all of the city departments that had been leasing space in various buildings, and to revitalize Chandler’s historic downtown.
Prior to development, the site consisted of abandoned structures and parking lots. As the project began, underground fuel storage tanks from a past service station were removed and soil contamination was remediated. The project’s footprint was pushed to the edges of the site to allow for a central courtyard that provides shaded walkways, captures evaporative cooling from a central water feature, and channels prevailing winds. The office building is lifted above the ground plane to create a breezeway to channel southeast and western winds through the site.
The complex reduces potable water use by utilizing low-flow fixtures and high-efficiency drip irrigation. Blow-down water from the cooling towers and condensate from the HVAC systems are captured and non-chemically treated for use in supplementing irrigation. In the summer, no potable water is used for interior and exterior systems, but the cooler months of winter mean less water is generated so some potable water use is required then.
To reduce cooling requirements, passive shading strategies were employed. The western office tower façade features an artistic shading system dubbed “Turbulent Shade,” which is a faceted, hinged structure of 1,800 perforated stainless steel panels that move with the wind. At night, colored LEDs highlight the installation. The one-story buildings on site use different combinations of strategies such as underfloor air distribution, variable air volume supply, demand-control ventilation, and photo-sensor light controls. The city is in discussions to install a 330-kilowatt PV array on the parking structure, which would reduce the ECI to 33.6 kBtu per square foot pet year and meet 2030 Challenge targets of a more than 60 percent reduction.
Commissioning activities are ongoing and operational energy use is being tracked though Energy Star’s Portfolio Manager program. An occupant survey also will be conducted.
BY THE NUMBERS
Building gross floor area: 187,000 square feet
Estimated percent of occupants using public transit, cycling, or walking: 10
Percent of daylight at levels that allow lights to be off during daylight hours: 80
Percent of spaces within 15 feet of an operable window: zero
Percent reduction of regulated potable water: 83
Is potable water used for irrigation: No
Percent of rainwater from maximum anticipated 24-hour, two-year storm event that can be managed onsite: zero
Total EUI (kBtu per square foot per year): 43
Net EUI (kBtu per square foot per year): 43
Percent reduction from national average EUI for building type: 53
Lighting power density (watts per square foot): 0.83
Total project cost at time of completion, land excluded: $47 million
Data and project information provided by architecture firm via AIA COTE Top Ten entry documents.
For an extended view into SmithGroupJJR's philsophies on sustainable design as well as a showcase of the firm's other green projects, click here. For more information on each project, as well as a database of past Top Ten projects, visit aiatopten.org.