Page 86 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

LEED Sustainable Sites 67

LEED 2009 CASE 2:
For areas with no local zoning requirements (e.g., some university campuses and military
bases), provide vegetated open-space area adjacent to the building that is equal to the
building footprint. (On campus settings this open space need not be necessarily contiguous
to the building.)
LEED 2009 CASE 3:
Where a zoning ordinance exists, but there is no requirement for open space (zero), provide
vegetated open space equal to 20% of the project’s site area.
ALL CASES:
• For projects located in urban areas that earn SS Credit 2, vegetated roof areas can
contribute to credit compliance.
• For projects located in urban areas that earn SS Credit 2, pedestrian-oriented hardscape
areas can contribute to credit compliance. For such projects, a minimum of 25% of the
open space counted must be vegetated.
• Wetlands or naturally designed ponds may count as open space if the side slope
gradients average 1:4 (vertical : horizontal) or less and are vegetated.

Potential Technologies and Strategies
Perform a site survey to identify site elements and adopt a master plan for development of
the project site. Select a suitable building location and design the building with a minimal
footprint to minimize site disruption. Strategies include stacking the building program,
tuck-under parking and sharing facilities with neighbors to maximize open space on the
site.

Calculations and Considerations
The LEED definitions for building footprint, development footprint, native (or indigenous)
plants, adapted (or introduced) plants, invasive plants, open space area, and previously
developed sites are given in App. B. Note the exceptions for SS Credit 5.2, and also as
applicable if SS Credit 2 is obtained, in the definition for open-space area as given in
LEED-NC 2.2 with the errata as posted in the spring of 2007:
Open Space Area is as defined by local zoning requirements. If local zoning requirements
do not clearly define open space, it is defined for the purposes of LEED calculations as the
property area minus the development footprint; and it must be vegetated and pervious,
with exceptions only as noted in the credit requirements section. For projects located in
urban areas that earn SS Credit 2, open space also includes non-vehicular, pedestrian-
oriented hardscape spaces.
The exceptions are with regard to vegetation and for all projects allow for wetlands
or naturally designed ponds to be included in open space if they have vegetated sides
leading down to them with low slopes (<25 percent). In addition, vegetated playing
fields may be included as open space. There is still some question as to whether sports
fields within stadiums count as open space. These special exceptions should be reviewed
through the USGBC CIR procedure.
For projects located in urban areas that also earn SS Credit 2, open space may include
vegetated roof areas and nonvehicular, pedestrian-oriented hardscape spaces (with the
caveat that at least 25 percent of the open space must be vegetated). Examples of these
pedestrian-oriented spaces include items such as pocket parks, accessible roof decks,
plazas, and courtyards.