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There are a broad range of strategies that are included under the Site umbrella. They include choosing the location of the building, building placement on the site, building shape, the amount of ground disturbed during construction, and the types of surfaces that will remain when construction is finished.
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Site Selection
When choosing a site for a building, there are many attributes to consider:
Building in an urban area, preferably an infill site (an undeveloped or underdeveloped site in the middle of a developed area), is less damaging to the environment than building out in the country.
There is less ground disturbance, because utilities are generally close, and if the site housed a previous building, some of the materials from that building may be reused. Also, urban sites are closer to amenities such as stores, banks, etc., reducing the need for carbon dioxide-emitting transportation.
Brownfields, or previously polluted sites, are also worth considering. With proper remediation, they can be made safe for development and the site and surrounding neighborhood can be rejuvenated through the addition of services.
Make sure that the site selected is not part of the natural habitat for any animal. Disturbing these areas can seriously affect the animal population and migration patterns. Also avoid sites with wetland areas, unless the use of these areas can be offset by the development of additional habitat close to the site.
The more solar exposure a site gets, the better the chance for using solar energy generation, solar water heating, or passive solar heating (using the heat from the sun to heat the building). Look out for tall buildings and trees that will inhibit sunlight from reaching the building. Southern exposure is best for passive heating, with east and west exposure being the most difficult to deal with. However, a site with poor solar exposure is not a poor site; it will just require creative building design to take advantage of what exposure there is.
Building Size and Shape
Believe it or not, the size and shape of a building can have a tremendous effect on its energy efficiency, the amount of materials used, and the disturbance of the surrounding environment.
Smaller buildings take less energy to heat and cool, so are generally better. If the building must be large, look at reducing the footprint (the area of the building actually touching the ground) by building multiple stories, so as to reduce the damage to the natural environment. However, be sure to consider the effect of building more stories on sun exposure and native vegetation. Also, some jurisdictions may have height limits for certain types of buildings, and this should be taken into account.
Buildings should be shaped to take advantage of solar exposure and heat gain. Generally this means long, skinny, rectangular-shaped buildings, with the long side facing south. This allows the most sunlight to flow into the building, helping with daylighting and passive solar heating. Site conditions may not allow this, so each building will need to be evaluated on a case by case basis.
Building Orientation
As mentioned briefly above, the direction a building faces and its location affect the ability to use passive solar heating and daylight harvesting. By analyzing the path of the sun at different times of the year, the orientation of a building can be optimized to receive the most light and heat when needed. The amount, size, and type of windows installed will help to modulate the exposure in extreme cases, and increase exposure when available.
Site Disturbance
By reducing the footprint of the building and the amount of ground that must be dug up during construction, the integrity of the surrounding habitat can be preserved. This also helps to reduce erosion and dust, as well as transfer of soils from the site. Native vegetation and topsoil should be left undisturbed as much as possible.
Stormwater
Sustainable construction strives to reduce the building’s footprint on the environment. By treating or containing the stormwater on-site, this lessens the impact of a building on the local infrastructure. Treatment can be most easily accomplished by filtering the water through natural landscape and earth filters. These usually take the form of bioswales, which are depressed areas that stormwater runs into where it is treated and held by the plants and soil until it is evaporated or sent out to the stormwater infrastructure through perforated piping.
Another strategy is to actually hold the water on-site, usually for use in the building. Filtered rainwater can be used for flushing toilets or landscaping irrigation. There are also systems available that can treat the water to drinkable standards. These re-use systems require the installation of underground holding tanks, filtering systems, and a secondary piping system for the filtered water.
Hardscapes and Heat Islands: Any surface area that is covered by impervious materials is called a hardscape.
These areas include parking lots, sidewalks, patios, and other paved or concrete areas. These areas are considered undesirable for two reasons:
(1) they do not absorb rainwater, so contribute to the need for stormwater treatment or containment (see Stormwater above), and
(2) they store the radiant heat of the sun during the day and release it at night, creating what are called “heat islands.” Heat islands are considered bad because they change the natural wind and weather patterns of a local area. If you’ve heard of the phenomenon of downtown areas creating their own weather, then you know what effect heat islands can have.
The effects of these areas can be reduced by lowering the amount of hardscape on a site. Using covered or in-building parking, open pavers, permeable asphalt and concrete, and lighter colored concrete are all strategies to reduce heat islands and stormwater build-up.
Sourced:
Green Building Guide 101
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