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September 15, 2000
The concept of "green" design in simple terms means "to design, construct and maintain a building in such a way that it will minimize impacts on its environment throughout its life."
By "environment," we mean not only the outdoor environment, but also the indoor environment that people experience during their daily routines.
There are a lot of owners and design professionals wondering where the whole "green" notion came from and why they should care about it. To answer these questions, you don’t have to go very far back in history or forward into the future to see why green design is important.
Since 1950, we have seen unparalleled social changes in the world in terms of population growth and technological advances, with corresponding uncontrolled pollution and creation of waste. As we head into the next century, this trend is only going to continue.
As society’s needs have changed over the last 50 years, the building industry has played a major role in keeping pace with the demands.
Today, one-third of the electricity generated in the United States goes to heat, cool, ventilate and light commercial buildings. The building industry commandeers 40 percent of the total global use of raw materials annually. It uses half of the earth's mined, harvested and dredged raw materials every year. Commercial buildings also produce 35 percent of the carbon dioxide emissions. It’s easy to see why the building industry should lead the charge toward sustainable design.
To understand how green design will work on a project, one must think on a holistic scale about all the processes involved in a building throughout its life cycle. Design professionals and owners should not limit their influence on green design by simply specifying "first cost" elements such as low-emmissivity windows, nonpolluting paints, and low-flow toilets and then just stopping.
The holistic approach takes a "cradle-to-grave" implementation process for a building project, calculating cost and effect from the day a project is conceived until the day the facility is no longer used, that is, its "life-cycle" costs.
It’s important to note that green buildings do not necessarily cost more than conventional ones. Take, for example, the idea of introducing outside air into a building. While it is true that this may cost more initially due to the need for a more complex HVAC system or a smarter building shell, the reduction or elimination of mechanical system requirements can offset these extra costs in a matter of years. In a recent scenario of this type on an 84,000-square-foot office building, the simple payback based on energy savings was just 4.4 years.
However, the most significant benefits of green design are the impacts on occupants.
If you were to ask typical office employers what qualifies as their largest company expense, it will most likely be salary costs. Green workplaces typically have lower absenteeism and lower staff turnover. Published reports have shown 6 to 16 percent productivity increases from employees who have good lighting, ventilation and indoor air quality. Many elements of green design are focused specifically on these factors, leading to increased employee satisfaction.
Sustainable design encourages design, construction and operation professionals to optimize a building’s environmental, social and economic performance.
A holistic design approach should start by setting goals for the project, covering a number of specific project areas: sustainable site planning, improving energy efficiency, conserving materials and resources, safeguarding water and improving indoor air quality.
Site planning: There are numerous ways to improve site planning on projects. A few examples have involved reducing light pollution by providing no more exterior lighting than necessary, and choosing light fixtures which direct light downward. Fixtures which allow light to escape upwards waste energy trying to light up the night sky.
Another expample is to simply select a light-colored roofing material. Dark-colored roofs absorb heat and create unnatural pockets of warm air.
Vegetated roofing is also becoming increasingly popular due to the wide variety of benefits it provides. As well as reflecting heat, it reduces stormwater runoff, improves stormwater quality and provides insulation for the building. Vegetated roofs often take the form of landscaped plazas, providing an asset to those who work in the building.
Improving energy efficiencies: Improving energy efficiencies in electrical and mechanical systems is a concept that most people are familiar with. However, thinking on a holistic scale, designers should consider drawing as much energy as possible from ambient sources such as the sun and wind. One example would be to adjust the pitch of a building’s roof to optimize its angle, thereby allowing more natural light and ventilation into the building.
Conserving materials and resources: Many of us recycle glass, aluminum, plastic and paper daily, but recycling in green design can mean reusing entire buildings or major building elements.
One current example of this practice is recycling the Kingdome, where 65 percent of the crushed concrete is being reused onsite to raise the field level for Washington’s new football/soccer stadium. New types and uses of recycled design materials are being developed almost daily.
Conservation of existing resources can also take a variety of forms, with sometimes two and three levels of benefit. Procuring lumber from certified forests is one way to know that the lumber on a project comes from a supplier practicing good product stewardship, which in turn enhances resource longevity.
For concrete, the incorporation of up to 50 percent fly ash into the mix increases durability, reduces costs and reduces cement demand and therefore the amount of carbon dioxide emissions generated from cement production (1 pound of carbon dioxide per 1 pound of cement).
Safeguarding water: Water use for a building is reduced by specifying high efficiency fixtures for plumbing and irrigation demands. Using drought-resistant plantings helps to further reduce the amount of water used for irrigation. Many projects already use detention tanks and bioswales, which reduce stormwater runoff and improve water quality. Some projects are now opting to retain rainwater and use it to irrigate landscaped areas during dry periods. "Gray water" systems conserve water on site by capturing used water from sink drains and recycling it to flush toilets.
Improving indoor air quality: There are many reasons to improve the indoor air quality for a building. Health and happiness of the occupants will be affected by the quality of the indoor environment. Specifying finish materials that have low-emitting VOCs or something as simple as providing operable windows in a building will greatly improve the indoor air quality by allowing fresh air to circulate in the space.
A growing trend among many municipalities in the United States is to encourage the implementation of green building practices for projects within their jurisdiction. The city of Seattle recently adopted a sustainable building policy that is tied to the LEED (Leadership in Energy and Environmental Design) rating system.
The LEED’s rating system assigns points for meeting the criteria set forth in the document, with projects rated as bronze, silver, gold and platinum. For city of Seattle-funded projects, a minimum goal is to attain a silver rating.
Green design can and should affect all of us in the design and construction industry. While the desire to achieve high standards of sustainable design may initially be driven by LEED ratings and other external forces, it is clear that a long-term perspective of holistic design is in the best interest of us all.