The USGBC has recently released the newest version of LEED (v3, 2009). As of June 27, all new projects will need to register with version 3. Version 3 boasts several advancements, including harmonization, credit weightings, and regionalization, as well as an updated LEED-online.
"The LEED Green Building Rating Systems are voluntary, consensus-based, and market-driven. Based on existing and proven technology, they evaluate environmental performance from a whole building perspective over a building’s life cycle, providing a definitive standard for what constitutes a green building in design, construction, and operation," (USGBC, LEED 2009). LEED was first introduced in 1998, with three new versions having been introduced between then and now. LEED 2009 has taken the highlights of the previous versions, as well as incorporated some major modifications that will make it a more user friendly resource to better serve building professionals.
Harmonization: In the latest version of LEED, credits and prerequisites from all commercial and institutional rating systems have been consolidated and aligned based on their most effective common denominators, so credits and prerequisites are now consistent across all 2009 LEED rating systems.
Credit weightings: In LEED 2009, a specific amount of points has been allocated to each credit, weighted based on their ability to impact different environmental and human concerns. More points will be awarded for design strategies based on 13 environmental impact categories. LEED 2009 uses the U.S. Environmental Protection Agency's TRACI environmental impact categories as the basis for weighting each credit. It also takes into consideration the National Institute of Science and Technology's (NIST's) weighting system, developed to compare environmental impact categories and weight them against each other. All LEED rating systems now have 100 possible points, with 10 possible bonus points.
The LEED 2009 credit weighting process involves three steps. First, a reference building is used to determine the environmental impacts in 13 categories associated with a typical building pursuing LEED certification. Next, the relative importance of building impacts in each category are set to reflect values based on the NIST weighting system. Finally, data that quantifies the building impact on environmental and human health is used to assign points to each individual credit.
Regionalization: The new version of LEED also awards points based on regionally specific environmental issues. For a projects specific location, up to 4 points are available if they address that region's specific environmental issues.
LEED-online: The updated LEED-online in version three is now a faster and more user friendly resource. The improved design has a more intuitive interface, greater help capabilities, and allows for better communication between project teams and certifying boards.
Visit the USGBC website for more information about the newest version of LEED.