An insatiable appetite for energy, a burgeoning world population, and a heightened awareness of climate change are focusing global attention on sustainability, an issue that may very well determine the future course of civilization. Sustainability can be defined as a characteristic of a process or state that can be maintained at a certain level indefinitely (Wikipedia, 2007). Sustainability was further defined in 1987 at the World Commission on Environment and Development (the Brundtland Commission) as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (UNEP, 2007). The pursuit of a sustainable lifestyle today is of paramount importance for future generations. There are now more than six billion people on Earth, and together we are placing unprecedented strains on the planet's ability to cope. Our natural environment provides the basic conditions without which humanity could not survive. Life on our planet is contained within the biosphere, a thin and irregular envelope around the earth's surface just a few kilometers deep around the radius of the globe. Here ecosystems purify the air and water that are the basis for sustaining life. They stabilize and moderate the earth's climate. Soil fertility is renewed, nutrients are cycled, and plants are pollinated. Through scientific research, we are now able to appreciate the complexity of this web of interacting natural processes, yet we are still a very long way from understanding exactly how they all fit together. What we do know is that if any part of the web suffers a breakdown, the future of life on our planet will be at risk. The twentieth century saw a fourfold increase in human numbers and an eighteenfold growth in world economic output. These increases have resulted in unsustainable patterns of consumption and the use of environmentally unsound technologies (Topfer, 2007).
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Achieving sustainability calls for the stewardship of all the natural systems of our planet, with everyone taking responsibility for solving the environmental problems we face today and will continue to face in the future. Good stewardship is the responsibility of all individuals, communities, businesses, and governments worldwide. While being environmentally conscious once meant recycling old newspapers and turning off the water while you brushed your teeth, now nearly every aspect of our lives--from the buildings we live and work in to the extracting of raw materials from the earth--is being radically rethought. Common sense should tell us not to pollute our environment. We do not have an infinite amount of natural resources at our disposal, and our planet is not growing along with the world's population. The next industrial revolution is the emerging transformation of human industry from a system that takes, makes, and wastes to one that celebrates natural, economic, and cultural abundance (MBDC, 2007).
The industrial framework that dominates our lives can now be thought of as primitive. It is conceived around a one-way manufacturing flow--considered a "cradle-to-grave" lifecycle. This cradle-to-grave flow relies on brute force for manufacturing products, and it seeks universal design solutions ("one size fits all"), overwhelming and ignoring natural and cultural diversity. And it produces massive amounts of waste--something that does not even exist in nature. In response to widespread environmental degradation, many industries, businesses, and communities have adopted the strategy of minimizing waste, pollution, and natural resource depletion, but this strategy, known as "ecoefficiency" is not a strategy for long-term success as it seeks to make the current destructive system sustainable. Ecoefficiency is a depletive approach. Minimizing toxic pollution and the waste of natural resources are not strategies for real change. Designing industrial and manufacturing processes, along with commercial and residential buildings, so they do not generate toxic pollution and waste and decrease the use of natural resources in the first place is true change. This is the "inconvenient truth" surrounding the green craze: We're paying little attention to the practice of sustainable design. Sustainable design is a real, practical, and long-term practice that could make a huge contribution to energy savings and environmental health around the world if fully embraced and adopted on a global scale. According to U. S. Government data, buildings account for 60% of the raw materials used in the United States and 40% of non-industrial solid waste. Unlike some industries, which can find substantial ways to cut back on the use of materials during the production process, the building industry will always need materials. The question becomes: What are the best materials and products to use? To address this question, consideration has to be given to the overall life cycle of the materials and of the facility and building site as a whole (Greenbiz, 2007).
Sustainable Building Design
Sustainable design can be applied to every structure, from a single-family home in the suburbs to a neighborhood public school to a downtown office building. It can encompass numerous architectural styles and functions, varying according to the needs of the client and the site. Sustainable design takes a long-term, multidisciplinary (holistic) approach to development that considers a building as a cooperative whole. The multidisciplinary method means that every team member--architect, mechanical engineer, civil engineer, landscape architect--influences important building elements. Mechanical options will affect architectural decisions, and architectural elements will determine the size and complexity of mechanical systems. Sustainable design regards a building as a totality that should operate in concert rather than as a collection of individual parts working in isolation (Carter, 2007). This approach brings together building design, energy efficiency, indoor environmental quality, material selection, site planning, resource efficiency, and water use to boost energy savings, and makes the most of all the building's elements. Sustainable design takes into consideration the building structure, its systems, and its site location as a whole and examines how they will best fit together to save energy and reduce environmental impact. Perhaps the key principle of sustainable design is its focus on environmentally sensitive development, design, and construction, which should produce an absolute minimum of pollution and aim to repair environmental damages of the past. Sustainable design and construction practices usually fall under five broad categories: site, energy, materials, indoor quality, and water.
Site planning that embodies sustainable design doesn't disrupt the landscape: it's responsive to and respectful of the site, site resources, climate, and other natural conditions. How a building fits onto a site can significantly influence energy consumption. In the United States, a north-south orientation provides more effective solar control. Fixed overhangs, landscaping, and other shading devices on a building's southern exposure are useful elements in passive solar control (Carter, 2007). Providing structures with unobstructed southern exposure gives the south side of buildings as much exposure to sunlight as possible during daytime working hours. With little or no extra cost, a building can usually be oriented with its long face within thirty degrees of true south, creating energy savings without changing the design (Klustner, 2007). If windows cannot be utilized or located to the best advantage, they can be tinted or coated. Tinting can eliminate glare and absorb solar heat. Products are available that control the amount of total solar heat and visible light that are transmitted. New tints have been developed that are spectrally selective. Some allow daylight in and keep heat out, while those intended for use in northern regions allow maximum solar gain. Tinting may increase the need for lighting in some cases, but that should be compensated for by the reduced cooling demand (Carter, 2007). Landscaping can help reduce a building's energy consumption. Deciduous trees can provide shade in the summer and permit sunlight to strike the structure directly during the winter. North-side evergreens provide an effective windbreak and weather barrier. Sustainable landscaping seeks to use native plants that don't require special care or irrigation. Landscaping and proper site orientations are important aspects of sustainable design, with opportunities to use a location's natural advantages.
Buildings consume approximately 37% of the energy and 68% of the electricity produced annually in the United States, according to the U. S. Department of Energy (Greenbiz, 2007). Significant gains can be made in efforts to combat global warming by reducing energy use and improving energy efficiency in buildings. The right mix of appropriate government regulation, greater use of energy-saving technologies, and behavioral change can substantially reduce carbon dioxide emissions from the building sector--which accounts for thirty to forty percent of all global energy use according to a recently released report from the United Nations Environment Programme (UNEP) Sustainable Construction and Building Initiative (SBCI). The report, Buildings and Climate Change: Status, Challenges and Opportunities, says many opportunities exist for governments, industry, and consumers to take appropriate actions during the life span of buildings that will help mitigate the impacts of global warming. The report focuses on the building sector and conservatively estimates that the building sector worldwide could deliver emission reductions of 1.8 billion tons of carbon dioxide. A more aggressive energy-efficiency policy might deliver over two billion tons or close to three times the amount scheduled to be reduced under the Kyoto Protocol. Achim Steiner, UN Under-Secretary General and UNEP Executive, said: "Energy efficiency, along with cleaner and renewable forms of energy generation, is one of the pillars upon which a decarbonized world will stand or fall" (UNEP, 2007).
In the lifetime of an average building, most energy is consumed, not for construction, but during the period when the building is in use--that is, when energy is being used for heating, cooling, lighting, cooking, ventilation, electronics, and other daily needs. Sustainable design strives to conserve energy by constructing buildings that minimize energy use and utilize renewable sources of power.
Advances in the efficiency of small-scale power-generating units and developments in the energy marketplace are enhancing the role of on-site power production in sustainable design. The efficiency of on-site generation is enhanced because it eliminates the energy lost as an inevitable result of the long-distance transmission of electricity from a central utility plant to the building. Facilities such as office buildings, government facilities, schools, shopping malls, health care facilities, airport terminals, hotels, and apartment buildings have sufficient electrical demand to justify on-site generation. Advances in power generation technology through improvements in natural gas engines and natural gas turbine generators have reduced the installed cost and increased the output of small units to where they are feasible for many applications. Eventually, buildings will be powered by nonpolluting fuel cells or clad with photovoltaic panels that produce electricity from sunlight, conceivably becoming net energy producers. Until that happens, sustainable design should continue to seek to exploit the most renewable of energy resources, the sun (Carter, 2007).
Passive solar design is the technology of heating, cooling, and lighting a building naturally with sunlight rather than with mechanical systems because the building itself becomes the system. Basic design principals are large south-facing windows with proper overhangs as well as utilizing tile, brick, or other thermal mass material used in flooring or walls to store the sun's heat during the day and release it back into the building at night or whenever the temperature drops. Passive solar designs can also include natural ventilation for cooling. Incorporating passive solar designs can reduce heating bills as much as 50% (United, 2007).
Solar electricity, or photovoltaic technology, converts sunlight directly into electricity. Solar electric systems all consist, basically, of three main items: modules (solar cells are typically combined into modules that hold about 40 cells) that convert sunlight into electricity; inverters that convert that electricity into alternating current so it can he used by most appliances and computers; and sometimes batteries that store excess electricity produced by the system for emergency backup power or for nighttime use. Today's modules can be built into glass skylights and walls. Some resemble traditional roof shingles. In over 30 states, any electricity not being used by a building's solar electric system can be fed back to the electric grid for credit from the utility company through an agreement called netmetering (United, 2007).
Building material choices are important in sustainable design because of the extensive network of extraction, processing, and transportation steps required for production of the product. Sustainable building materials should be selected whenever possible. Sustainable, low-impact materials are: nontoxic, recycled and recyclable, renewable, local, standard sizes, durable, and long-lasting.
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The recycled content of a material can be described as either postconsumer or postindustrial content. Specifying materials with a high recycled content is a method of saving both processing and manufacturing energy. Some building materials that can contain a high percentage of recycled material include reinforcing and framing steel, concrete and masonry, gypsum wallboard, and acoustic ceiling panels.
During the construction phase, a large amount of waste material is generated through construction, demolition, and land-clearing procedures. Recycling on the job site is becoming more economical as the cost of disposal increases, regulations become more stringent, and material costs rise. Developing a waste management plan can help realize cost and environmental savings. When it comes to construction materials, there are three main sustainable goals: reduce materials use, use renewable resources that are environmentally friendly, and reduce construction waste. As the growing global economy expands the demand for raw materials, it is no longer sensible to build using environmentally damaging, nonrenewable building materials.
In a sustainable design facility, the indoor quality should be physiologically and psychologically healthy. Indoor quality encompasses the entire indoor environment, including air quality, the presence of moisture and humidity, thermal and sensory conditions, and lighting. The indoor environmental quality (IEQ) of a building has a significant impact on occupant health, comfort, and productivity. Among other attributes, a sustainable building should maximize day lighting, have appropriate ventilation and moisture control, and avoid the use of materials with high VOC (volatile organic compounds) emissions.
Water and Wastewater
Sustainable design conserves water through low-water-use design, storm water management, and wastewater treatment and reuse. Using large volumes of water increases maintenance and life-cycle costs for building operations and increases costs for municipal supply and treatment facilities. Water efficiency measures in commercial buildings can easily reduce water usage by 30% or more, according to some estimates, by utilizing low-flow fixtures coupled with sensors and automatic controls. Other effective methods of reducing potable water use include capturing and reusing roof runoff water for nonpotable applications, using industrial wastewater or gray water from bathroom sinks to flush toilets, collecting rainfall in on-site cisterns, and water-efficient landscape irrigation. As water use and allocation becomes a topic of growing concern around the world, sustainable design for water use will need to be scrutinized more, with the end result being cost-saving efficiency and environmental responsibility. (Greenbiz, 2007).
Sustainable design does not signify a decline in the standard of living or a reduction in the functionality of structures. While it is a realistic approach that acknowledges that economic growth must continue, it emphasizes protecting the environment and meeting the needs of society. Sustainable design doesn't violate or compromise conventional design goals and objectives, but refines them to produce innovative solutions that can be justified economically as well as ecologically. A sustainable building affords increased functionality and improved comfort through a combination of improved technology, innovative ideas, and proven practices. It will be easier and less expensive to heat and cool and provide a healthy environment for its occupants. Sustainable design is an affirmation that economic growth and development can take place without harming our biosphere or limiting options available to future generations (Carter, 2007).
Sustainable design takes into consideration the building structure, its systems, and its site location as a whole and examines how they will best fit together to save energy and reduce environmental impact. Perhaps the key principle of sustainable design is its focus on environmentally sensitive development, design, and construction, which should produce an absolute minimum of pollution and aim to repair environmental damages of the past. Sustainable design and construction practices usually fall under five broad categories: site, energy, materials, indoor quality, and water.
Using the five broad categories for sustainable design, divide students into five groups, assigning each group of students a sustainable design category. Each group should evaluate their school building (or any building that students readily have access to) to determine if it conforms to sustainability design practices in relation to the group's assigned category. Have each group list those aspects that are not sustainable and then incorporate possible design solutions that would create sustainability. Students should also identify areas that they deem sustainable and justify those products, materials, or systems. After each group has completed its design challenge, the students should gather as a class and discuss their findings.
Carter & Burgess. (2007). Technically speaking. Retrieved September 2, 2007 from www.c-b.com/industryInfo/ infoBrief/sustainableDesign/index.asp
Greenbiz.com. (2007). Backgrounders. Retrieved August 20, 2007 from www.greenerbuildings.com
Klustner, K. (2007). The six degrees of building efficiency. Retrieved September 4, 2007 from http:// greenerbuildings.com
MBDC. (2007). The next industrial revolution. Retrieved September 10, 2007 from www.mbdc.com/c2c_nir.htm
Topher, K. (2007). Sustaining life on earth. Retrieved August 19, 2007 from www.cbd.int/convention/guide. shtml?id=changing
UNEP SBCI. (2007). Buildings can play a key role in combating climate change. Retrieved September 3, 2007 from www.unepsbci.org/
United States Department of Energy. (2007). High Performance Buildings. Retrieved September 1, 2007 from www.eere.energy.gov/buildings/highperformance/ technologies.html
Wikipedia. (2007). Sustainability. Retrieved September 3, 2007 from http://en.wikipedia.org/wiki/Sustainability
Stephen Baird is a technology education teacher at Bayside Middle School, Virginia Beach, VA and adjunct assistant professor at Old Dominion University. He can be reached via email at Stephen.Baird@VBSchools.com
Figure 2. Commercial and Industrial Building Use of Energy. Most of the energy consumed by commercial buildings is devoted to heating, cooling, and lighting. Sustainable design affords opportunities to reduce these loads while increasing the comfort level and the occupants' productivity. Commercial and Industrial Building Use of Energy Lighting 30% Space Heating 22% Space Cooling 18% Water Heating 7% Office Equipment 6% Other 6% Ventilation 6% Refrigeration 3% Cooking 2% (Source: U. S. Energy Information Administration). Note: Table made from pie chart.…