U.S. green building LEED design standards

LEED

Increasingly, the drive to develop green construction in the United States has grown from a small number of architects and contractors, who are responding to concerned consumers, to an actual trend that extends nationwide and includes mandated green buildings in many major cities. The degree to which this interest is now established throughout the country is exemplified by the formation of the Leadership in Energy and Environmental Design (LEED) certification in 2000 by the Washington, D.C.-based U.S. Green Building Council (USGBC). Numerous companies, organizations and institutions are now following the LEED guidelines to ensure that they receive certification, and many are discussing the pros and cons of making LEED mandatory for all new construction in the U.S.

According to its Web site, the nonprofit organization USGBC is committed to a prosperous and sustainable future for the United States through cost-efficient and energy-saving green buildings. The USGBC mission is "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." Presently, over 20,000 organizations and 100,000 LEED Accredited Professionals in all 50 states and 91 countries are creating projects that are expected to reach the $60 billion mark this year.

In order that all buildings meet similar high standards, USGBC has established a certification system that rates the design, construction and operation of green commercial and residential construction on energy savings, water efficiency, CO2 emission reduction, indoor environmental quality, and stewardship of resources. The buildings are evaluated on environmental impact and performance for their life cycle and receive credits based on this evaluation. Each rating system is organized into five environmental categories: Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, and Indoor Environmental Quality. An additional category of Innovation in Design concentrates on sustainable building expertise and design. Regional bonus points recognize the importance of local conditions when determining the highest quality environmental design and construction practices (USGBC).

Each obtained LEED credit is based on the U.S. Environmental Protection Agency's Tool for the Reduction and Assessment of Chemical and other Environmental Impacts (TRACI) environmental impact categories. The certification also considers the weightings developed by the National Institute of Standards and Technology (NIST). The criteria consist of the following:

1) A reference building is used to estimate environmental impacts in 13 categories associated with a typical building pursuing LEED certification; 2) The relative importance of building impacts in each category reflect values based on the NIST weightings; and 3) Data that quantify building impacts on environmental and human health are used to assign points to individual

Credits (USGBC).

Each of these credits receives points based on the relative importance of the building-related impacts it addresses, resulting in a weighted average. Credits directly addressing the most important impacts receive the greatest weight. This greater rating based on impact is a new criteria that USGBC placed into effect in 2009, so that buildings having the highest potential for making the greatest environmental change receive the most credits. In total, the points place an emphasis on the building's reduction of energy consumption and greenhouse gas emissions, the embodied energy of water and energy of materials, and as applicable, solid waste. There are four certification levels based on the number of points achieved: Certified, Silver, Gold, and Platinum (USGBC).

When LEED was updated in 2009, it included a new requirement that those desiring .certification "must commit to sharing with the USGBC and/or GBCI all available whole-project energy and water usage data for a period of at least five years." Under LEED 2009, certified buildings are still not required to actually meet their forecasts for reduced energy and water consumption, which was another criticism of the program (Baker Donelson).

The types of buildings are also categorized. 1) New Construction and Major Renovations consists of performance standards that certify the design and construction of commercial or institutional buildings and public and private high-rise residential buildings; 2) Core and Shell Development addresses the speculative development market where project teams do not control a whole building's design and construction; 3) School Design for both new construction and major renovations of existing school buildings; 4) Existing Buildings: Operations & Maintenance to promote high performance, healthful, durable, affordable, and environmentally sound practices in present buildings; and 5) Commercial Interiors to certify the design and construction of tenant spaces for office, restaurant, healthcare, hotel/resort and educational buildings (USBGC).

A variety of new and existing buildings have received LEED certification over the recent years. The following are ten examples of these awards:

1) Office Depot: Gold Award, New Construction. In 2007, Office Depot recognized its 39 million square feet of commercial real estate in North America was responsible for significant carbon emissions and a solid-waste footprint. As a prototype for future construction retail locations, the Austin, Texas, construction followed the LEED certification process. Included is a roof that reflects sunlight and cools the store, requiring less energy for air conditioning; high-efficiency heating, ventilation and air conditioning units; water-efficient fixtures in restrooms; locally sourced and recycled materials; and skylights that adjust with the sun and provide natural day lighting. The business offers green line merchandise, which sold $1.6 billion in the U.S. And Europe in 2007. They created a detailed LEED-EB Credit Report documenting sustainable purchasing of office supplies, technology, and furniture. Shopping carts are refurbished, and the store has an recycling center for cell phones, rechargeable batteries, ink and toner cartridges, paper and electronics.

2) Clearview Elementary: Gold Award, New Construction. This K-4 school in Hanover Pennsylvania was designed to protect the children's health and teach environmental protection. The $6.35 million 43,000-square-foot building cost less than 2.5% more to build than average elementary schools in Pennsylvania. The building saves about $18,000 a year on energy. The collaboration of the school's designers and faculty led to an eco-friendly school with a curved energy-efficient sunscreen offering shade from the sun, an acoustical backdrop for outdoor presentations, and a sundial for hands-on learning. Other features include a floor-mounted, air-diffusing system that responds to temperature, humidity and carbon dioxide level changes; low- and no-volatile organic compound paints, non-solvent-based adhesives, and low-emitting carpeting; 40% of building materials harvested and manufactured within a 500-mile radius; recycled insulation, fiberboard panels and rubber flooring; over 75% of construction waste recycled; over 30% less potable water and waterless technology in bathrooms.

3) AMB Morgan Business Center: Gold Award, Core and Shell. This is a

347,000-square-foot speculative industrial building in Bloomingdale, Georgia, that includes considerable cost savings on operating expenses and healthier work environments for tenants; project costs were $.70 per square foot; high albedo materials, including white-painted facades, cool roofing and concrete driveways to reduce heat island effect and save on cooling; sensor-controlled lighting and HVAC systems to save an estimated $100,000 annually in energy; water consumption usage reduction of 67% through drought-tolerant native plants outside building and water-efficient plumbing fixtures inside helped reduce water usage by 67%, or 2,000,000 gallons annually.