What's Happening from Environmental Building News
Restructuring of LEED Moves Ahead
The U.S. Green Building Council (USGBC) currently has over nine LEED rating systems covering commercial and residential buildings, interiors, and exteriors, all the way up to entire neighborhoods, and several more systems are on the way. Even as LEED continues to proliferate, however, a movement continues among USGBC leadership to make it more unified, scientifically rigorous, and regionally appropriate. First discussed at the Greenbuild Conference in 2006 (see
EBN
Vol. 15, No. 12), USGBC announced at Greenbuild 2007 that it would continue to move LEED toward a “bookshelf” of credits while incorporating both structural and technical changes. At the same time, weighting of environmental priorities, life-cycle assessment (LCA), and regional credits all promise to affect LEED and its point structure.
The long-term goal of the bookshelf system, according to Scot Horst, chair of the LEED Steering Committee, is to allow a user to enter specifics about a project into the LEED registration tool and have the system find credits that are appropriate—essentially creating a custom rating system. In the shorter term, the bookshelf will simplify the work of committees as they create customized rating systems for specific building types, such as laboratories or day-care centers.
Before either of these can happen, however, the various LEED rating systems must be aligned and their credits harmonized. Currently, although most of the rating systems have similar structures, they have different numbers of points and often have credits with similar intents but different specific requirements. Extracting specific credits and placing them on a universal LEED bookshelf, said Horst, “allows us to see all of the ideas in LEED separate from a rating system, which allows us to look at the ideas and create new systems more quickly and easily.”
As they are aligned, the rating systems will also be recalibrated to a 100-point scale. This structural shift to aligned 100-point systems paves the way for technical changes that the Steering Committee plans to propose and hopes that the membership will adopt. To this end, USGBC and its consultants are now analyzing each credit in the various LEED systems and categorizing the environmental benefits of those credits. The category structure they’re using is based on the U.S. Environmental Protection Agency’s Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI), which is also the basis of the Building for Environmental and Economic Sustainability (BEES) LCA tool.
Once the credits are organized by impact categories, the 100 points will be distributed among those credits based on the relative importance of each impact category. Eventually, USGBC’s membership will be invited to weigh in on those priorities. In the meantime, USGBC will use the results of a weighting exercise that the National Institute of Standards and Technology (NIST) performed in June 2007 for the BEES tool.
To make LEED more responsive to regional environmental impacts, the Steering Committee also wants to expand the available innovation points from four to six and add four new regional points, bringing the total number of points in each system to 110. The regional points, according to Horst, would be available to a project team to emphasize credits that are particularly important to their project, effectively adjusting the weighting of the system to meet regional needs. For example, a project in Arizona might choose to claim extra points for water conservation. Adding points to address regionalism “allows us to do it in a manageable way that doesn’t throw off the entire system,” said Horst.
A third technical change would incorporate LCA into LEED as an alternate compliance path for some of the materials and resources credits. Doing so “will help project teams see the holistic effects of materials in a whole new way,” said Horst. The LCA approach would have project teams looking at groups of materials as building assemblies as opposed to earning credits for specific material attributes such as recycled or rapidly renewable content. Modeled on the approach used in the U.K. with its
Green Guide to Specification and adopted recently in Green Globes (see
EBN
Vol. 16, No. 3), LEED would offer a catalog of assemblies that have been evaluated using LCA software and assigned a rating or score. A design team could earn points for a project based on its use of high-scoring assemblies. This approach would allow teams to “think differently about materials without having to know all of the details of LCA,” said Horst.
Horst notes that the changes to LEED are far from final. “We need to figure out exactly how we’re going to present this for public comment and member ballot,” he said. Whether the structural and technical components of the Steering Committee’s proposal will be put out for comment and ballot together or separately has not yet been decided, but Horst expects something will be presented to the membership in the spring of 2008. After these changes are implemented, users will still register projects for specific systems, although the credits in those systems may change somewhat in the alignment process. “If LEED is a car, it’s going to look exactly the same,” said Horst of the user experience. “What we’ve done is put a different engine in it.”
– Nadav Malin and Allyson Wendt
For more information:
U.S. Green Building Council
Washington, D.C.
800-795-1747, 202-742-3792
www.usgbc.org
December 1, 2007
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Source: USGBC
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