This past November, at the annual Greenbuild International Conference and Expo, architect Norris Strawbridge, FAIA, purposefully left one building out of his talk on how to respond when a project’s sustainable measures don’t reap the expected efficiencies and savings. The Institute for Global Citizenship (IGC) at Macalester College in St. Paul, Minn., performed just the way Strawbridge and his colleagues at Bruner/Cott in Cambridge, Mass., had hoped it would. “Sometimes things don’t go the way you planned,” Strawbridge says, “but they didn’t happen on this building. It required surprisingly little fine-tuning. It’s a very simple little building.”
The first academic building in the Midwest to earn a LEED Platinum rating when it was completed in 2009, the building’s LEED certification helps express the IGC’s mission to prepare students for leadership in an increasingly borderless world with shared challenges such as climate change. “It made sense to demonstrate or recognize the notion that sustainability is integrally woven into the issues of being global citizens,” explains David Wheaton, Macalester College’s vice president for administration and finance. “There’s a reason why they call it global warming. Having a conventional, inefficient building would seem to be counter to that.”
To both symbolize the sustainable commitment and to prompt greater conservation amongst the building’s occupants, a dashboard in the lobby prominently displays energy savings in real time, which has helped make it popular on campus tours.
Yet the design approach ultimately was brick-and-mortar practical. Emphasis was placed on energy efficiency rooted in a tight building envelope. Concrete framing holds thermal mass to minimize temperature fluctuations, while the façade of stone, copper, and triple-pane glass is insulated with ultratight R-40 walls and an R-70 roof, all buffeted by 7 inches of spray-foam insulation. This tight envelope, in turn, allowed for an efficient all-radiant mechanical system.
“We kept it simple and followed the rules,” Strawbridge says. “Architects know if you orient it the right way (as we did, north–south), if you control the windows, and if you use the strategy that people have used in that particular climate for a long time, it will work. There was this thick and robust envelope with the right amount of openings for daylight.”
Indeed, energy modeling data has validated the focus on the building’s envelope. A comparable building designed to code would have used 98 kBtu per year, the architects explain. The IGC was designed to use 43 kBtu annually. Even better, it turned out to use just 35 kBtu in its first year and 33 kBtu the second. “The best buildings in the world at the time we were designing this were around 20 or 25,” Strawbridge says. “We were in hailing distance of those, but without renewables. Things like the envelope performance were not necessarily measured by LEED directly. We’d do blower door tests and talk with contractors about thermal breaks. The construction industry in Minneapolis is different. They really care about what they’re doing. They said, we get the idea here, but maybe by doing it this way you get a better result. We called it ‘LEED and beyond.’ ”
Water is inexpensive and plentiful enough in the Land of 10,000 Lakes, so little financial incentive exists for conservation. But it’s a major global issue and thus became an important feature in the building. Dual-flush toilets (chosen after the client rejected composting toilets) and low-flow fixtures, coupled with the lack of irrigation needed by the native-plant landscaping, have helped reduce water usage by about 40 percent compared to a code-designed building. “People had to get used to the landscaping, because when you think of a campus you think of green lawns,” says Bruner/Cott architect Jason Forney, AIA. “But there was a story to go along with it.”
That story keeps people coming back, too. “We take tours from grade-school kids to visitors from other campuses to building owners in the twin cities,” Macalester’s Wheaton says. “There’s been a steady flow since we opened in ’09. It’s a destination in a broader sense.”
Brian Libby writes about architecture and sustainability from Portland, Ore.
How quiet is too quiet? Though located along a busy thoroughfare, the Institute for Global Citizenship’s tight building envelope coupled with a lack of mechanical air systems (it uses radiant heating and cooling) is so quiet that it took some acclimation. “It made a different acoustic environment than people were used to,” says architect Jason Forney of Bruner/Cott. “People eventually described it as serene rather than eerie.” The remaining ambient noise, which bounced off hard interior surfaces, seemed proportionally louder until the architects employed sound-absorption measures.
Learn to sail and flush. Imported equipment, such as a chilled sail from Germany (which provides both convection and radiant heating and cooling) and dual-flush toilets from Australia, caused delays not only because of delayed delivery but also as a result of subcontractors’ unfamiliarity with the products. “The plumbers had their own views of how to do things,” Bruner/Cott’s Norris Strawbridge recalls.
Create a fundraising tool. Though Bruner/Cott was challenged to design sustainably within a conventional building’s budget, Macalester College found that fundraising was actually easier because of the design. “A couple major gifts came because of the sustainable features,” Macalester’s David Wheaton explains. “They might not have given to the project otherwise. Whatever premium we faced, we felt it was more than covered.”
Dashboard sells metering. At first, the architects had difficulty convincing the client to invest in post-occupancy metering for energy and water. “Our clients sometimes say, ‘We did the energy model. We know it will be fine.’ But we wanted the metering to know how the building was functioning,” Strawbridge says. “We convinced them by introducing the idea of a dashboard.” Now during the building’s frequent tours, the dashboard is a first stop. “There are enough features in the building to talk about,” Wheaton says, “from energy performance to water usage to materials—all of those are of interest to people.”