By Bronwen Ledger
Counting on GreenEngineering
On most summer days in Austria, it was enough simply to open a window in a home and let in the breeze in order to stay cool. Enough, that is, until the European Commission issued an energy directive t...
On most summer days in Austria, it was enough simply to open a window in a home and let in the breeze in order to stay cool. Enough, that is, until the European Commission issued an energy directive to encourage house designs with walls well sealed to save heat losses and that would fully exploit solar gains. As south-facing windows in new houses became larger, the thermometer inside rose. Many homes built according to the supposedly energy-saving rules are now using mechanical air-cooling systems to maintain comfortable temperatures.
There are people in the construction industry who seize with glee on such stories of green building programs go wrong. They see them as examples of how misguided energy efficiency and other green building initiatives can be, and continue to build in the old ways. The same people–often developers and building owners–are very wary of attempts to introduce standards for green buildings, believing they would just add one more band of red tape to restrain their business activities and one more huge cost to
their bottom line.
But to Susanne Geissler’s audience the story held a very different message. Geissler, of the Austrian Institute for Applied Ecology, told it to teams of environmental experts and designers at the Green Buildings Challenge ’98 conference in October. To them the example of the overheated Austrian homes shows how complex environmental issues are, and precisely why it is important we put more energy and attention into studying environmental building methods. Only with more research and evaluation, they believe, will we be able to avoid mistakes and more accurately predict results.
The delegates at the Green Buildings Challenge conference came from 14 different countries–everywhere from Australia, to Japan and the United States–to discuss a system called GBTool for assessing and rating the environmental performance of buildings. The system has been developed over the past two years under the sponsorship of Natural Resources Canada and is largely the brainchild of two people: Nils Larsson of Natural Resources and Professor Ray Cole of the University of British Columbia.
Larsson is only too aware that they face resistance from developers and owners in their attempt to introduce environmental performance standards to the building industry. “We just have to find a positive way of having everyone see this as value-added,” he says. “The trick is how to implement a system [a green labelling system] without alienating building owners who may see it as just another burden.”
Coming down the line
Alienated or not, owners will have to pay attention to green building rating systems within a few years as the public demands more environmentally responsible buildings. The environmental movement is showing no signs of slowing down, and with the signing of the Kyoto Agreement in December 1997, the government could well end up regulating cuts in energy use and greenhouse gas emissions. In Canada buildings currently produce up to 18% of the carbon dioxide that is contributing to global warming. In the U.S. and other industrialized countries buildings use up to 40% of the total energy produced by fossil fuels, the chief culprit in producing greenhouse gases.
Green building assessment and labeling programs will play an important role as the green movement gathers momentum. They provide an objective way of measuring environmental performance and ensuring that the designers and developers of green buildings are not making empty claims. If governments introduce a tax credit or exchange system for green buildings they will become especially critical.
While we already have codes and standards for measuring energy use such as ASHRAE 90.1 and Canada’s Model National Energy Code for Buildings, green building assessment systems like GBTool cast a much wider net. They can be used to assess existing buildings, or to rate the predicted performance of a building still in design. And they take a holistic approach, accounting for not just a building’s projected or actual energy use, but also factors such as the energy and resources extracted in the construction materials, how much water a building consumes, and the impact of the structure upon the ecology of the site. Many countries have labelling systems already. The best known in the English speaking world is BREEAM (Building Research Establishment Environmental Assessment Method) that originated in the United Kingdom but is also here in Canada, and LEED (Leadership in Energy and Environmental Design) which is becoming the standard in the United States.
GBTool’s key difference is that it was written as an international assessment tool. Consequently it can be tweaked in myriad ways to account for the extreme complexity and particularity of different geographic regions and situations. It does this by shifting the weighting of scores it assigns to various conditions. It accounts not only for climatic differences, but also for issues such as scarcity of agricultural land, distance from raw materials and ecological sensitivity. A building’s water use, for example, is not such a critical factor in a water-rich region as it would be in an arid zone like Arizona, so GBTool can assign to a building a score carrying less weight in that category. Similarly, it might customize scoring for energy use to reflect the fact that a building is linked to a district heating system. In other words, the intent was to make an assessment tool that can reflect the complexity of each different building situation.
GBTool–But how complex can it be?
The drawback in inventing a system to fully describe complexity is that the system ends up being extremely complicated itself. The problem users found with GBTool was that it took so much time and effort to complete. The 14 teams that participated in the Green Buildings Challenge and used it to assess case study buildings had no less than 4,000 criteria to answer. Even after 1,500 of these parameters were stripped out, the program remains cumbersome and time consuming. The organizers estimate that each of the national teams invested up to $100,000 in the whole two-year process of developing and testing the model, and about $25,000 applying it to each case study building.
No commercial developer has that kind of cash to spare on using the system. Larsson says, “We have to get these costs down.” In a summary paper given at the end of the conference entitled “A Strategy for GBC-2000 and Beyond,” he writes: “All participants found the effort required to satisfy the information demands of the current system to be more than anticipated…. Some of the reasons had to do with the difficulty of obtaining good data, even for buildings that have recently been completed, but others had to do with the GBTool system itself.”
Larsson’s partner in crime, Ray Cole, agrees that the GBTool perhaps is too detailed, but he points out that they had to walk a tightrope. “That was what was exposed throughout this whole process,” he says. “These assessment methods must have a balance between sophistication and simplification. We somehow have to get that balance right. If you go over too far to making a system too comprehensive, too demanding, then it is not going to find any appeal in the market place. But then if you make it too simple then it is not fulfilling its primary role of giving you this really good, comprehensive analysis.”
What else made working with GBTool more difficult was its unfamiliarity. Most of the national teams in the Green Buildings Challenge are used to working with other programs–indeed several of the players helped to write other programs. Having to learn the new GBTool program as they went along just added to the burden of time and effort they had to spend trying to apply it to their buildings.
That unfamiliarity will also be a hurdle to overcome if GBTool is to establish itself as an international rating system. Catherine Coombs of Steven Winter Associates of the U.S. was at the conference. She thinks they would continue to use LEED rather than GBTool: “In terms of the design community the inte
rest is mainly in LEED because that’s the only program that’s been recognized in the United States at this point. With GBTool we would have to use it as secondary to the main rating system and market it ourselves because it hasn’t enough recognition right now.” Nor does Klaus Hansen of the participating Danish team think they will adopt the GBTool: “The Green Building Conference has been a good experience for us,” he says, “especially because a wide range of issues has been considered. But I don’t think that [the tool] will be adopted in Denmark as it is. We believe in a more life-cycle assessment-based model using the tool developed by the Danish Building Research Institute.”
Still, Coombs has nothing but praise for the Canadian effort: “These kinds of tools are useful because they push the ball forward, and elevate the design process and its importance.” And Cole says the conference was an important crucible for exchanging expertise: “Just developing the assessment tools has involved national team efforts and international cooperation. Assessment methods become an incredible filter for a whole range of different discussions and research into the technology. They become a wonderfully focusing device for a previously disparate area.” He also thinks that countries which do not yet have green building assessment programs may adopt GBTool as a model.
Besides wrestling with the issue of how complex and rigorous an environmental assessment system can be without becoming a bureaucratic and financial nightmare for its users, the conference highlighted many other key issues that must be settled before such systems are widely adopted. Larsson identified several questions in his summary paper. Should an evaluation system’s criteria be purely “green,” for example, as the purists think, or should they be broadened to embrace issues such as how well a building serves the users, its cost, and even Its aesthetics? Other questions rose over the program methods. Some like Hansen’s Danish team, wanted more emphasis on life-cycle analysis. The concept of “reference” or control buildings, which is familiar to North Americans from energy codes, caused “much grief and confusion” to the teams from elsewhere. The teams did not like having to design the building twice, and many simply ignored the requirement. Larsson concludes: “In future work, the overlapping concepts of reference criteria and industry benchmarks will probably have to merge and be greatly simplified.”
Missing the boat
Where do consulting engineers fit into all this? Right in the middle, although you would never know it from the small number of consulting engineer firms at the conference. Perhaps the most important conclusion that participants in the Green Buildings Challenge and similar conferences on green building design have come to is that collaboration between disciplines is essential. “The indirect spin-offs have been enormous,” Cole says, “because when you have these comprehensive assessment tools you have to bring all the team members together to address the issues. When you just have one issue it tends to fall in the domain of one particular consultant, whereas comprehensive assessments involve a lot of synergy and interaction.” He raves enthusiastically about the German case study buildings, where “the integration between architecture and engineering is almost seamless,” and recalls the same kind of cooperation between engineering and architecture going into Canadian buildings such as the C.K. Choi Building at the University of B.C. and the C-2000 Bentall Building in Richmond, B.C.
Despite this emphasis on holistic design, Larsson concludes that it is not important for an evaluation system to ask whether a design team was interdisciplinary or not. He believes that such information is “of historical interest only” because evaluation programs are not concerned with who is responsible for making a green building, but only the degree to which it reaches the goals.
Consulting engineer firms should take note. Just as product manufacturers and corporations have taken over mechanical and electrical design in energy performance contracting, so firms other than consulting engineers are quickly moving into the dedicated environmental building field. Only a couple of well known consulting engineering firms, Keen Engineering of Toronto and Reid Crowther of Edmonton, were at the Vancouver conference to present case studies (see sidebars). They were far outnumbered by architects and specialist environmental technology firms.
In not playing a bigger part in the emerging field of dedicated and serious green building design, consulting engineers are not only missing an opportunity for work but also to do something good for the environment. Green building is also a great chance for consulting engineers to assume a role that they have long coveted. The emphasis on holistic design means mechanical, electrical, structural and building science consulting engineers must take a more prominent role. They can be involved in generating the design from the beginning instead of sitting on the sidelines until the architect comes to call. And with their special practical skills in analysis, engineers can be extremely valuable players. The further we delve into green building, the clearer it becomes that it is a very complex field, and one that demands both a scientific and an imaginative eye. Only with both perspectives will we avoid mistakes such as the Austrian homes that opened up too widely to the heat of the sun. CCE
For more details about GBTool and the Green Buildings Challenge, contact Mark Riley, Tel. (613) 769-4002, or Nils Larsson (613) 760-1242. E:mail email@example.com. Web site NRCan: http://nrcan.gc