Buildings represent a huge investment, not only of money and time, but also of the world's resources. In constructing and occupying buildings, we consume vast quantities of materials and generate a major portion of the world's environmental pollution. According to the Worldwatch Institute, buildings consume more than 40 percent of the energy utilized in the world each year and, in so doing, release into the atmosphere one-third of the carbon dioxide and two-fifths of the compounds that cause acid rain. In the United States, our buildings use about one-sixth of the fresh water consumed each year and a quarter of harvested wood. Our buildings release about half of the fluorocarbons that escape into the upper atmosphere and destroy the ozone layer that shelters us from the sun's ultraviolet rays. About 40 percent of our landfill material comes from construction projects. We see in these statistics that buildings are responsible for many forms of environmental degradation. They place a heavy burden on the earth's resources, most of which are nonrenewable and finite, and they jeopardize the health and welfare of humanity. Thus it is increasingly urgent that we learn to build and operate buildings in a sustainable manner.
Sustainability may be defined as meeting the needs of the current generation without compromising the ability of future generations to meet their needs. When we burn fossil fuels, we consume a portion of a finite, nonrenewable resource so that it will not be available a generation or two in the future. We also generate greenhouse gases that promote global warming. This will confront a near-future generation with the problem of a world in which glaciers and ice caps are shrinking, seas are rising to perilous levels, and weather is violent and unpredictable. When we build sprawling residential subdivisions on fertile land once used for growing food crops, we reduce the stock of agricultural land that will be available to future generations. When we use wood from forests that are not replanted with trees, we make it more likely that our children and grandchildren will find wood to be a scarce, expensive commodity.
We have it in our power to change this situation. We can reduce substantially the energy needed by our buildings. We can meet much of this need with solar and wind energy, both of which are renewable, nonpolluting, and available on the site itself. In many instances, we can build on land that has been recovered from abusive practices of the past such as contaminated industrial sites, demolished tenement apartment buildings, and land on which poor agricultural practices have led to extensive soil erosion. We can build with wood from certified forests, ones that are harvested and replanted in such a way that they will produce wood forever. We can build with wood recovered from old buildings that have been taken down. In each of these examples, we are building in such a way as to pass on to future generations the means to build in a similar fashion.
A number of organizations and manufacturers are working diligently toward sustainable construction practices (also referred to as "green" building). Some relate to particular resources such as forests. Some have to do with recycling materials such as scraps of gypsum wallboard or worn-out tires into new building materials: gypsum wallboard, roofing slates. Some are promoting renewable energy sources such as solar, wind, and photovoltaic technologies. Some concentrate on improving the energy performance of buildings through better thermal insulation, more airtight construction, and more efficient heating and cooling machinery. And some focus on educating architects and engineers, the designers of buildings, who by siting and orienting buildings intelligently, configuring them appropriately, selecting materials knowingly, and detailing the construction properly, can greatly reduce their impact on the earth and its resources.
Several organizations are working to educate architects and engineers in how to build sustainably. Prominent among these is the United States Green Building Council, which sponsors the LEED system for evaluating the sustainability of a building. LEED stands for Leadership in Energy and Environmental Design. The evaluation process is summarized by a checklist that is used in evaluating the degree of sustainability that is attained in a building. It is instructive to look at the categories on this checklist. The first broad category, "Sustainable Sites," includes, among other factors
• whether a building will improve its site or degrade it;
• whether the users of the building will be able to come and go by foot, on bicycles, or by public transportation so as to save fuel and reduce air pollution;
• the extent to which the site is disturbed by the new construction; and
• how storm water is managed (is it stored for use on-site, used to recharge the aquifer in the area, or dumped into a storm sewer?).
The second category, "Water Efficiency," includes
• use of stored storm water or "gray" wastewater (discarded wash water that does not contain human wastes) for irrigation;
• innovative wastewater treatment; and
• use of fixtures that reduce water consumption.
Category 3, "Energy & Atmosphere," relates to
• efficiency of the building's heating and cooling devices and systems;
• use of renewable energy resources on the site; and
• the potential of the building to contribute to ozone depletion.
Category 4 is "Materials & Resources." It includes
• recycling of building materials and building wastes;
• waste management on the construction site;
• recycled content in building materials used;
• use of local and regional materials, which consume less fuel in transportation, rather than materials that must be transported long distances;
• rapidly renewable materials; and
• wood from certified forests.
"Indoor Environmental Quality," the title of the fifth category, covers
• elimination of tobacco smoke;
• ventilation effectiveness;
• air quality during construction;
• use of materials that do not give off toxic gases;
• control of chemicals used in the building;
• thermal comfort; and
The sixth and last category is titled "Innovation & Design Process." It is an open category that awards credits for original design ideas that lead to more sustainable buildings. It also awards credits if an architect or engineer who has been accredited as a LEED expert is involved in the design of the project.
Although this list is still evolving, it is already serving as the basis for certifying the degree to which a building is sustainable. Additionally, it is a powerful vehicle for raising the environmental awareness of architects, engineers, and builders.
Throughout the pages that follow, you will find information relating to sustainability in the design, construction, and operation of buildings. Every chapter tells how to build in such a way that resources are used wisely, energy is conserved, waste products are reduced, and buildings are made comfortable, durable, and healthy with the minimum possible cost to the environment. Many of these practices are old and well-known. Some are new and innovative. In either case, architects and engineers must become familiar with them and use them more consistently if we are to pass on to our children and grandchildren a world as lovely, hospitable, healthy, and resource-rich as the world into which we were born.
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Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.