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Buildings are the largest contributor to the greenhouse gas emissions that cause global warming—and making buildings more energy efficient is one of the most immediate and measurable ways to address this growing concern. The advantages of “green buildings” are well documented: 30 percent energy savings, 35 percent carbon savings, 30-50 percent water savings, and 50-90 percent waste cost savings.
The U.S. Green Building Council (USGBC) is a nonprofit organization founded, in the words of its mission statement, “To transform the way buildings and communities are designed, built and operated, enabling an environmentally and socially responsible, healthy, and prosperous environment that improves the quality of life.” A steering committee of the USGBC developed the Leadership in Energy and Environmental Design (LEED) Green Building Rating System™ to provide universally understood and accepted tools and performance criteria that encourage and accelerate global adoption of sustainable green building and development practices. LEED encourages construction practices that meet specified standards, resolving much of the negative impact of buildings on their occupants and on the environment. Green buildings in the United States are certified with this voluntary, consensus-based rating system.
The USGBC was formed in 1993 and in 1998 the LEED 1.0 pilot program was released. By March 2000, 12 buildings had been certified under the pilot program. During the pilot period extensive revisions were underway and by March 2000 LEED 2.0 was released to the marketplace.
In just eight years this rating system has truly changed the market and how architects practice. As of May 1, 2008, 3.5+ billion square feet of building projects (10,000+ individual projects) have registered intent to seek LEED certification, with dozens more signing up every day.
LEED certification is increasingly respected in the building industry as recognition of social responsibility and leadership in an emerging field. Many state and local governments, and some federal agencies such as GSA, now recommend or require that construction projects earn a LEED rating. And, in addition to reaping the economic benefits of sustainable design—from improved worker productivity and health to lower operating costs—LEED-certified buildings in a few states and cities can now qualify for financial incentives.
THE LEED RATING SYSTEM
The initial LEED rating systems were for six types of projects, specific to various building types or building projects: New Construction & Major Renovations, Existing Buildings (which is for maintenance and operations, not rehabs of historic/existing buildings), Commercial Interiors, Residential, Core & Shell, and Multiple Buildings. Today there are several other rating systems, for Neighborhood Development (which is just coming out of the pilot phase), Schools, Retail, and Healthcare. The one most commonly used is LEED-NC: New Construction & Major Renovations.
There are four levels of LEED recognition—certified, silver, gold, and platinum—which are reached through a point system using a LEED score card. Scores are tallied for different aspects of efficiency and design in six categories:
1. Sustainable Sites
2. Water Efficiency
3. Energy & Atmosphere
4. Materials & Resources
5. Indoor Environmental Quality
6. Innovation & Design Process
In the past year USGBC has comprehensively updated most of the LEED rating systems and is about to launch LEED Neighborhood Development to the market. Many of these changes are more scientifically based and in many cases better represent historic preservation and social values.
INTEGRATING PRESERVATION VALUES INTO LEED: THE SUSTAINABLE PRESERVATION COALITION
The Sustainable Preservation Coalition has been advising the USGBC on ways to incorporate preservation, social, and cultural values into LEED. And now there’s progress to report!
The National Trust for Historic Preservation created the Sustainable Preservation Coalition in 2006 to influence further development of the LEED Building Rating Systems to better recognize historic and existing buildings. The Trust partnered with several national organizations that were developing separate sustainability agendas, including the American Institute of Architects, Association for Preservation Technology International, National Park Service, General Services Administration, and National Conference of State Historic Preservation Officers. All the partners realized we could make a bigger impact on incorporating historic preservation with green building values by working together.
The coalition’s first goal was to meet with the USGBC to start a conversation on how to improve its rating systems to better reflect the importance of existing buildings to sustainable stewardship of our planet and its limited resources.
LEED does much to encourage more sustainable development, and historic buildings can achieve the highest LEED rating. Currently it’s been noted that:
1. Out of 69 points, about 20 are building-type neutral, meaning any building type—renovation or new construction—can get these points.
2. Another 10 points directly support preservation activities.
3. Any existing building can basically get a “certified” rating with very little effort.
4. Getting “silver” requires a bit more effort and “gold” is readily achievable.
But while historic buildings are achieving gold and platinum LEED ratings, the Sustainable Preservation Coalition believed the rating system could be improved, because the current versions of LEED:
1. Overlook the impact of projects on cultural value
2. Do not effectively consider the performance, longer service lives, and embodied energy of historic materials and assemblies
3. Are overly focused on current or future technologies, neglecting the advantages of many traditional building practices.
The coalition’s meeting with the president of USGBC (Rick Fedrizzi) and the director of LEED Technical Development (Brendan Owens) in March of 2007 was quite successful, ending with them inviting us to help them prepare preservation metrics (standards of measurement) for the revised versions of LEED, which have been in development over the past year. We developed a white paper that identified eight basic metrics we believed were lacking in LEED and have been advising the LEED staff on the revisions.
LEED’s rapid success presents its stewards, the USGBC membership, with opportunities to continue to improve the rating systems to ensure that future buildings certified under its criteria are even greener than the stock in the pipeline to date. This year USGBC unveiled its most comprehensive amendments to LEED since 2000: LEED 2009, also referred to as Version 3 (v3).
The U.S. Green Building Council has provided drafts of revised rating systems for five project types: New Construction & Major Renovations, Core & Shell, Commercial Interiors, Schools, and Existing Buildings. The council held two public comment periods (and received a record 5,800 comments during the first one). The final version was approved by USGBC members on November 14, 2008 and was officially announced on November 18. These latest and most comprehensive edits to LEED look familiar, but the way they will be used is different.
Among its many changes, LEED 2009 includes some that will directly favor the preservation and continued use of existing buildings. (We are specifically discussing the changes to NC: New Construction & Major Renovation, since that is the most commonly used rating system for large rehabilitation projects, although CS: Core & Shell is sometimes used as well.)
One of the biggest changes is how LEED Accreditation will work with the new versions of LEED, and how Project Certification will change. In 2008, USGBC spun off a new organization, called the Green Building Certification Institute (GBCI), to manage its accreditation and AP testing process. Beginning in January 2009, GBCI will take over the certification process as well. Peter Templeton, the founding Director of LEED, was recently announced as the new President of GBCI. USGBC will now handle all the development of LEED and green building practices, and GBCI will handle all credentialing and certification, ensuring an independent third-party verification of the testing and certifying processes. Please read more about the new accreditation process at http://blogs.nationaltrust.org/preservationnation/?p=1898.
The GBCI accreditation website is now live, and the new accreditation timeline is as follows:
• FEBRUARY 2009
o LEED Green Associate Exam - Beta Test
o LEED AP + Operations and Maintenance Exam - Beta Test
• MARCH 2009
o LEED AP + Homes Exam - Beta Test
• SPRING 2009
o LEED Green Associate Exam – Launch
o LEED AP + Operations and Maintenance Exam – Launch
o LEED AP + Design and Construction/Interior Design and Construction - Beta Test
o New Candidate Application
• SUMMER 2009
o LEED AP + Homes Exam – Launch
o LEED AP + Design and Construction/Interior Design and Construction - Beta Test
o New Credentialing Maintenance Program - Launch
WEIGHTED POINT SYSTEM
The biggest complaint about the current LEED rating systems (such as LEED NC 2.2) is that every credit is worth the same one point—and that there is no weighting by impact or priority. But this is all changing. In LEED 2009, points are distributed based on consideration of the relative environmental or human benefit provided by that item.
The credits in the new version are now weighted according to Life Cycle Assessment (LCA) criteria. Life Cycle Assessment is a scientific methodology to calculate the environmental performance of a product over its full life cycle. By applying LCA to the existing credits, the total possible score for a project has been increased from 69 to 100 points, or actually 110 since there are various bonus points.
The six measurement categories remain the same, but the points have been reallocated according to the results of the LCA weighting. Sustainable Sites has gone from 14 possible points to 26. Water Efficiency has increased from 5 possible points to 10. Energy & Atmosphere has increased from 17 possible points to 35. Materials & Resources has increased from 13 possible points to 14. Indoor Environmental Quality has remained at 15 possible points. Innovation & Design has increased from 5 possible points to 6. And a new section of Regional Bonus Credits with 3 possible points has been added.
Here are some ways that the weighted system will better support preservation and smart growth goals:
We’ve all heard about the building that’s been constructed in the suburban fringe going for LEED platinum. The increase of Credit 2—Development Density & Community Connectivity, under the category Sustainable Sites, encourages the construction or renovation of buildings within a dense community to help dissuade that kind of activity. This credit has increased from 1 point to 5 points.
Also under Sustainable Sites, Credit 4.1—Alternative Transportation—Public Transportation Access has been increased from 1 point to 6 points. Again, this encourages the placement of buildings in dense communities with access to various forms of public transportation.
The category Innovation & Design Process will now offer the opportunity to earn Innovation & Regional Bonus Credits. The USGBC Chapters are being given the responsibility to develop 3 additional points to reward projects that address environmental areas of concern in a project’s region—for example, having operable windows and shutters in areas with high humidity, or courtyards that allow cross ventilation in tropical regions. This change will benefit many traditional buildings, whose siting and design often demonstrate low-energy solutions to meeting the requirements of their specific climate.
The weighting system has been constructed in a way that if environmental and societal priorities shift, the focus of LEED can also shift by adjusting weightings across the key impact categories—without requiring a complete reconfiguration of LEED.
ALTERNATE COMPLIANCE PATH FOR EXISTING BUILDINGS
A completely new Alternate Compliance Path is being developed that will benefit existing buildings, entitled “Life Cycle Assessment of Building Assemblies.” This will be an optional path to use the Materials & Resources Credits based on the durability and embodied energy of existing materials as determined through LCA criteria.
The science behind LCA is young and there are many different approaches to it. USGBC has an LCA working group, made up of the most experienced LCA scientists on the continent, who are developing a special LCA Credit Calculator that quantifies the life cycle impact of various materials and building assemblies.
The Alternate Compliance Path was not ready for public review when the rest of the drafts for LEED 2009 were put out for public comment, but it will be available for use with LEED v3 in early 2009. Currently the intent is that any building already registered for LEED will be able to use the Alternate Compliance Path—even if the project is registered under one of the past versions such as NC 2.2. This credit calculator has been in beta testing and will move to project case study testing in the new year. The National Trust has offered our first LEED project, the President Lincoln’s Cottage Visitor Education Center as a case study and a way to further formalize our partnership with USGBC. We anticipate beginning this evaluation in early 2009.
The Sustainable Preservation Coalition is very supportive of this approach. While new construction can also use this path, we anticipate that existing buildings will rank the highest and achieve the most points.
LEED NEIGHBORHOOD DEVELOPMENT
One of the newest LEED rating systems is LEED ND – Neighborhood Development, which has been in a pilot phase for the past two years, and is now out for its first public comment period, project to close January 5, 2009. Anyone can comment during the public comment stage; you only need to be a member of USGBC for the final vote. A second public comment period for this project type is also planned, with the intention that the final version will go out for member vote in the summer of 2009.
LEED Neighborhood Development (ND) is in some respects as different from LEED 2009 as it is similar. It has a very different construct (4 sections instead of 6), was developed by a working group of three organizations – USGBC, Natural Resources Defense Council (representing the Smart Growth community) and Congress for New Urbanism – and focuses on infrastructure and the public realm, with buildings as just one component. But like 2009 it has the four recognition levels – certified, silver, gold and platinum. The National Trust for Historic Preservation has been advising the staff at USGBC for the past 6 months on the final edits to LEED ND and is very pleased to announce and discuss the changes that are out for public comment right now, as well as to encourage everyone to read the new system and send in comments.
“The development of LEED for Neighborhood Development speaks to the breadth of what ‘green building’ means,” says Sophie Lambert, the Director of LEED ND, on the USGBC website. “What was once a rating system solely designed for commercial construction is now evolving beyond single buildings to address development at the neighborhood scale.”
The LEED ND Rating System
LEED ND can be used on a single building, a Main Street, a community or even as a tool to retrofit suburbia. The pilot version opened for use in July 2007. The draft rating system was out for public comment in 2006/2007, during which time the National Trust reviewed and commented upon the program upon USGBC request. During the pilot stage, 239 projects were registered in 39 states and 6 countries, which has allowed for the identification of many conflicts and issues, some of which were exactly what the USGBC hoped that the National Trust would be able to help with. From a preservationist’s point of view, it is very exciting that some of the biggest changes to the pilot version of LEED ND involve historic preservation and existing buildings. USGBC speakers acknowledged this fact during their Specialty Update on Wednesday, November 19, 2008 at Greenbuild, and thanked the National Trust for its assistance.
LEED ND has four categories:
1. Smart Locations & Linkages (SLL)
2. Neighborhood Pattern & Design (NPD)
3. Green Infrastructure & Buildings (GIB).
4. Innovation & Design Process
Historic preservation values are particularly addressed in NPD Credit 1 - Walkable Streets and GIB Credits 4 – Existing Building Reuse & 5 – Historic Building Preservation & Reuse.
There have been 5 major structural changes to LEED ND since the pilot version came out.
1. Alignment wherever possible with LEED 2009. Changing the scoring to 100 points is one way that that is being accomplished, as well as trying to use the same terminology wherever possible.
2. The credits have been weighted, in not as complicated a way as the LCA system used for 2009, but weighting nonetheless.
3. Graphics have been added to clarify the descriptions.
4. USGBC has worked with the Center for Disease Control (CDC) to ensure that wherever possible the intents of each credit have been developed to reflect public health concerns.
5. Section 3, Green Construction & Technology has been fully reconsidered and even renamed as Green Infrastructure and Buildings. Extra teeth and requirements safeguarding existing and historic buildings have been provided. In total, 13 prerequisites are now required, up from 9 in the pilot stage.
The strongest part of the revisions is the better alignment of terminology, made in order to best utilize the agreed-upon and legal terminology and concepts as established in the National Historic Preservation Act, and adopted and implemented by states and local jurisdictions across the country. The Secretary of the Interior’s Standards for the Treatment of Historic Properties and Section 106, for example, are all referenced.
NPD Prerequisite 1 – Walkable Streets
The concept behind walkable streets is a really sound neighborhood design element. The major goal of this section is to promote walking, bicycling and transportation efficiency. This prerequisite, as well as the related Credit 1, provide guidelines for this section. The prerequisite credit does provide for an exemption for historic districts if their historic design does not follow these guidelines. “Projects located in a designated historic district subject to review by a local historic preservation entity are exempt from b. and c. if approval is not granted for compliance. Projects located in historic districts listed in or eligible for listing in a State Register or the National Register or designated as National Historic Landmarks, that are subject to review by a State Historic Preservation Office (SHPO) or the National Park Service, are exempt from b. and c. if approval is not granted for compliance.”
Green Infrastructure & Building Credits 4 & 5: Existing Building Reuse & Historic Building Preservation & Reuse
The language in the current draft has cut the points for these credits to a total of 2 from an original 4; nevertheless, these credits represent a much stronger recognition of historic preservation laws and concepts than has heretofore existed. The pilot version gave one point for keeping or reusing a historic building, and little of the recognized preservation terminology was used. The best part of both of these credits is a prerequisite that invalidates using either of these points if a historic building is demolished. “To achieve this credit, no historic building or portion of a historic building may be demolished as part of the project. An exception is granted only in instances where approval for such action is provided by the appropriate review body. For buildings listed locally, approval must be granted by the local historic preservation review board, or equivalent body. For buildings listed in a State Register or in the National Register of Historic Places, approval must appear in a programmatic agreement with the State Historic Preservation.” It is worth noting that it would still be possible, with this current construction, to demolish a historic building and simply not opt for either of these two credits, as it is only a prerequisite for these two credits, and not for LEED ND on the whole.
Should we expect more changes? Yes, and soon. The next revision, targeted for 2011, will actually change some of the credits, removing some and adding others.
The Sustainable Preservation Coalition will be working with USGBC to further incorporate more social and cultural metrics into the next LEED revision. These are some of the unquantifiable aspects of buildings. They include social sustainability (recognizing sites of architectural, cultural, and/or social significance); health and comfort (which includes rewarding buildings that enable occupants to, for example, open windows or otherwise manage and control aspects of their comfort and well-being); social capital (recognizing when older buildings contribute to a sense of place within their neighborhoods); and density (optimizing the location of a building to utilize existing infrastructure). We are planning a retreat with USGBC and other partners later this year to flesh this out.
To keep up with developments, check the National Trust’s Historic Preservation and Sustainability webpage and the “green building” blogs posted at http://blogs.nationaltrust.org/preservationnation.
Barbara A. Campagna, AIA, LEED AP, Graham Gund Architect of the National Trust, is the Chief Architect for the 29 Historic Sites operated by the National Trust and architectural leader of the National Trust’s Sustainability Initiative. She received the National AIA Young Architect of the Year Award 2002 and was the president of the Association for Preservation Technology International 2005-2007. Sources of information for this article include the website, and Chris W. Scheuer and Gregory A. Keoleia, “Evaluation of LEED Using Life Cycle Assessment Methods” Center for Sustainable Systems (Ann Arbor: University of Michigan, NIST)
High LEED ratings can be achieved with historic buildings. With its rehabilitation of the President Lincoln’s Cottage Visitor Education Center in Washington, D.C., the National Trust initially aimed for a silver rating but is now on track to earn gold. This project will also be used as a pilot to test the Alternate Compliance Path. Photo courtesy of the National Trust.
Building features designed to suit local climate conditions—such as operable windows, shutters, high ceilings, and cross-ventilation—may soon earn points toward LEED certification under a system of Regional Bonus Credits that is now being developed. Photo courtesy of the National Trust.