Page 106 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

LEED Sustainable Sites 87

FIGURE 2.7.3 Front of the Learning Center at the West Quad at the University of South Carolina.
The roof is partially vegetated and has walkways and architectural shading structures for
pedestrian access and use.

a partially vegetated roof. The roof is used for outdoor receptions as well as a means to
control the urban heat island effect.
Typically green roofs are divided into three categories: intensive, semi-intensive,
and extensive. Extensive green roofs usually have a small substrate depth (3 to 6 in) for
the vegetation to grow in and typically are planted with grasses and sedums which
require no irrigation. These roofs do not require high load-bearing structures for support.
Intensive green roofs, on the other hand, usually require high load-bearing support
structures, can include many types of vegetation such as trees, and have a much deeper
substrate (soil) depth, usually more than a foot. Semi-intensive roofs are somewhere in
between. Figure 2.7.4 shows an experiment on plants to test for species that might grow
best without irrigation on an extensive roof in central South Carolina. Figures 2.7.5,
2.7.6, and 2.7.7 are all photographs of the same new parking garage in Houston, Texas.
Figure 2.7.5 shows a northern exposure, whereas Figs. 2.7.6 and 2.7.7 depict exterior
and interior views from the southern wall, respectively. The “green wall” on the
southern exposure may aid in obtaining many credits related to the sustainable sites
category or perhaps an innovative point, even though it is not directly applicable to the
SSc7.2 equations.

2.8 SS Credit 8: Light Pollution Reduction

USGBC Rating System
SSc8 is worth one point in LEED 2009 and was worth one point in LEED 2.2. LEED-NC
2.2 lists the Intent for this credit as follows: