Metal choice meets aesthetic and environmental goals

March 2012 - When Arizona State University announced plans for a new downtown Phoenix campus to house its College of Nursing and Health Innovation, the fast-track, budget-driven project went to SmithGroupJJR, an architecture, engineering and planning firm. The firm’s Phoenix office drew on its own ingenuity and the attributes of copper to design a sustainable and unique structure that could meet several distinct requirements.

“Navigating a three-pronged client with diverse interests and goals inherently comes with complexity,” says Mark Kranz, AIA, LEED AP, design principal at SmithGroupJJR’s Phoenix office. “The owner, city of Phoenix, was interested in an urban building that could add to the architectural character of downtown and provide much-needed shade. ASU requested an iconic building to differentiate its new nursing college facility and to mark the gateway to their downtown campus. The College of Nursing and Health Innovation had needs of its own, which included accommodating the college’s vast growth and creating a branded identity on par with their national acclaim.”

Enhanced performance
The 84,000-square-foot building incorporated water conservation, energy efficiency, material conservation and indoor environmental quality measures. The building’s interior incorporates classroom, study and interaction spaces for students and faculty. The building’s ground floor also had to accommodate pedestrian flow. Copper provided a cost-effective and visually impactful exterior closure system. According to the Copper Development Association Inc., copper and its primary architectural alloys are active metals that, when subjected to the elements, tend to oxidize. This natural weathering offers architects a range of natural and weathered colors, as well as corrosion resistance. The metal’s superior thermal and electrical conductivity enhances building technologies and contributes to a structure’s overall environmental performance.

Kranz says copper brings myriad benefits to the building. “Because the material weathers naturally, you put it up once knowing that it’s going to last for 50 to 100 years. It literally requires no maintenance. Here in the desert, copper turns to a rich brown, a warm palette that complements the collection of ASU buildings. The copper sits nicely in the middle of the color and material palette and blends with the assortment of new and old buildings. Copper is also anywhere from 80 to 100 percent recycled.”

The copper panel profiles optimize relief and depth while eliminating the potential for oil canning or a perceived waviness in the flat areas of metal roofing and metal siding panels. The panels were affixed via a structural steel frame fastened with stainless steel Tek screws to a horizontal hat channel sub frame, which was attached to a steel stud framing system.

Panel system
“Copper panels clad all four elevations of the facility, with the fenestration calibrated to balance day lighting goals for the interior and solar protection,” says Kranz. “Perforated panels provide shading for stairs and balconies on the east and west facades, where the desert sun is most brutal. The perforated panels also provide shade while allowing these exterior spaces to self-ventilate.”

Copper Sales Inc., a division of Firestone Metal Products, Anoka, Minn., provided 15,000 square feet of UNA-CLAD architectural grade sheet copper (AGSC). The product is 99 percent copper with silver counting as copper, cold rolled from ingots of 122 or 110 alloy. AGSC copper conforms to ASTM B370 specifications with a tensile strength of 38 ksi and a maximum tensile strength of 46 ksi. UNA-CLAD is suitable for general sheet metal use in building applications and comes in flat lengths or coils.

Copper’s aesthetic qualities combined with its unique physical and mechanical properties provide a flexible material that allows designers and building owners to achieve their visual ambitions as well as performance requirements and cost goals.

According to Kranz, the project was completed in 2009 and has since generated 16 percent regulated energy cost savings through energy conservation measures, diverted more than 75 percent of construction waste from conventional landfills and reduced potable water by 59 percent through water conservation methods. Thirty-four percent of the building’s materials contain recycled content.

“Ultimately, the finished project coalesced collective goals in an impressive five-story building that welcomes students, residents and visitors to the downtown core and ASU’s downtown campus,” says Kranz. MM