The Secret Life of Buildings
Life-cycle assessments gauge the cumulative impact of a building’s materials and its operations—and they could be the future of green-building standards.
The U.S. Green Building Council (USGBC) has done an outstanding job in greening the industry. But as the LEED standard continues to evolve, the question is: What’s next?
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To get a feel for where the green building marketplace might head one day, go to GoodGuide.com and look up any of the 75,000 consumer products they rate, from air fresheners to yogurt. GoodGuide aggregates more than 200 technical databases into a ten-point scale to rank products—and the companies that make them—on their environmental, health, and social impacts. Some of the databases evaluate items over their entire life cycle, from the extraction or harvesting of their contents through manufacture all the way to disposal. In an instant you can compare the ecological virtue or negatives of any product to all of its competitors.
Imagine if some day a parallel rating system existed for buildings, one that rolled up all the ecological impacts of the materials over their entire life cycle and combined those with the impacts of building opera-tions. Such an evaluation would add breadth to LEED ratings by including more dimensions of ecological impacts. Like GoodGuide, the system would have to be independent, verifiable, and transparent.
There are signs of a growing demand for such transparency in green building. When Kaiser Permanente, the nation’s largest health maintenance organization, undertook to build millions of square feet of hospitals, they asked the Healthy Building Network, with its expertise in avoiding toxins in building materials, to help them go beyond simply minimizing volatile organic compounds from carpets and flooring.
“Kaiser looked to us, for example, to assess the materials in a carpet to avoid phthalates in the backing. Phthalates are endocrine disruptors, bronchial irritants, and asthma triggers,” says Tom Lent, a director of the network. “You need to look at all the industrial chemicals used in building materials and match them to medical hazards.”
Such fine-grained evaluation of the impacts of material typifies life-cycle assessment (or LCA), the method used by industrial ecologists to evaluate the gamut of an item’s ecological plusses and minuses. To be sure, LCAs themselves need some improvement. For one, they are very crude in how they address health issues from materials, like the phthalates in carpets.
An example can be seen in Energy-Star ratings, where a wall-mounted digital display screen might look highly energy efficient, but such thin-slice data misrepresents the overall picture. More than 90 percent of its environmental impact occurs during manufacture and disposal, according to Dara O’Rourke, an industrial ecologist at the University of California at Berkeley. An LCA would reveal impacts beyond the use stage. In theory, LCAs can generate a level of information that allows an architect to make more informed choices. LEED standards have brought ecological transparency where there was little or none before. But in some ways LEED ratings represent a black box that’s not easily penetrated.
The LEED governing group has begun using LCA evaluations to inform their green-building standards. Taking LEED certification to this next phase would present a better picture of a building’s cumulative ecological impacts. “We are proponents of radical transparency for architects, so they can drill down to find the data behind the claims,” says Lent. “The green-building world is peppered with labels but sparse on transparency.” “LEED is a first step,” commented Pedro Vieira, a member of the Consortium on Green Design at the University of California at Berkeley. “But it only touches the surface. [In theory] you can do an LCA of a building, assessing all the individual materials, water and energy used, as well as the logistics of producing them.”
Incorporating more LCA data into LEED ratings, and making those ratings easily comparable, would raise the.....
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