Birds & LEED™The phrase "green building" has been used for many years to refer, in a general way, to a structure that is environmentally friendly. A building with a low impact on the environment might, for example, lower its energy or water usage, or incorporate recycled materials in its construction. The term, however, proved unsatisfactorily vague. In the mid-nineties a strong interest in setting standards for "greenness" took hold.
The Leadership in Energy and Environmental Design (LEED) Green Building Rating System was soon developed, by a diverse group including architects, builders, engineers, environmentalists, material suppliers, and other interested parties. Today the LEED system is overseen by the United States Green Building Council (USGBC), which continually refines the standards through a consensus-based process.
The LEED certification program has enjoyed widespread acceptance and backing in the U.S. and beyond. More than 20,000 design professionals have undergone LEED training and accreditation. LEED-certified projects-over 6,000 of them-currently exist in more than 25 countries. Here, the USBG includes more than 8500 membership groups, who may help review certification criteria. All new Federal buildings must be LEED certified; in December of 2006 Washington, D.C., became the first large city to require all new buildings, including private ones, be certified.
To obtain LEED certification, building designs are measured against a checklist of targets in six categories (to be explained below): Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, Indoor Environmental Quality, Innovation and Design Process. And before embarking on the list, a building designer must first pass certain "prerequisites" in each category. In the Sustainable Sites category, for example, the designers must affirm they will avoid polluting the site during their construction activity. Each target is worth a certain number of credits, and to be certified, a design must earn a minimum of 26 of a possible 69. Credits are earned by such features as low-energy lighting, roof gardens, solar or geothermal heating, rain water collection for use in toilets and air-conditioning, and so forth.