Issue link: http://digital.canadawide.com/i/423872
M any in the engineering and architecture design community see retrofits of existing buildings as a potentially substantial portion of the available cost-effective options for generally "greening" the nation's buildings. It makes sense. Many of the buildings one could expect to see around in 2030 have already been built, and a good number of them between now and then will require an upgrade or retrofit of some sort. It is likely that a high percentage will occur in the context of new and more demanding codes. In Vancouver, for example, the city's Greenest City 2020 Action Plan has introduced tougher energy code requirements for both new and existing buildings. One of the aims of the action plan is to reduce greenhouse gas emissions of existing larger buildings classified under the city's building bylaw as Part 3 and Part 9 non-residential. Most in the design sector expect codes across Canada and the U.S. to continue to tighten with regard to energy efficiencies and other sustainability issues, but a range of concerns about rating systems is being aired these days. These have related, as one might expect, to specific systems like LEED, but also to rating systems in general and the kind of approaches that they tend to invite. One concern is that rating systems can lend themselves merely to setting boundaries that help with ensuring the "less bad," but don't really promote designs that embody attributes of sustainability. "One of the goals of a rating system is to transform the market with awareness," says Michael Blackman, a project engineer and sustainable design advisor at Read Jones Christoffersen Ltd. Design needs to maintain a focus on first principles and avoid being circumscribed by checklists. "The rating system and the checklists can constrain thinking," he says. Instead, a rating system can be used to help designers with a better understanding of first principles and find ways to apply them that both encourage and embody sustainable building attributes. Part of the greening of a building and its systems involves challenging assumptions, Blackman says. For a deluxe residential high-rise in Bangkok, windows that open were included in the package. Often, he says, designs for such projects in Bangkok don't bother with windows that open, given the hot and humid climate, and the demand for air conditioning. Conversely, including windows that opened for ventilation on such a project challenged assumptions about relying exclusively on air conditioning for temperature comfort. As a result, the amount of air conditioning used soon dropped to well below norms for such a building. "That means less HVAC, just by asking questions about assumptions," Blackman says. He believes the design community needs to be asking the big questions. On an individual project, that can mean starting by considering such issues as building orientation or wall assembly. Shifting to a broader perspective, he points to the extent of global housing demand. "The demand is huge. Globally, we need 20,000 new homes a day. But we need to challenge ourselves Sealing The Envelope Architects and engineers are the driving force behind green building design by Godfrey Budd The Okanagan College new trades facility, Kelowna, will use solar PV as an energy source as well as capture waste heat from a wastewater treatment plant. "The Okanagan climate helps. It's hot in the day and cool at night, making net zero quite achievable." – Birgit Siber, principal, Diamond Schmitt illustrations: kevin house exterior sunshades Photovoltaic array on south facing roof at 15-degree slope Fritted glass high- and low- operable windows radiant inslab heating and cooling. Fed by low temperature waste heat from wastewater treatment plant high performance envelope with 30 per cent window to wall ratio tom arBan tom arBan lisa loGan renderinG and inset Photos unless otherwise credited: courtesy diamond schmitt architects 25 per cent of the site incorporates edible plants or "crops" 14/ december 2014 Green building design