S.11 Heat Island Reduction

Intent
Reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimize impact on microclimate and human and wildlife habitat.

Recommended Performance Criteria

1. Non-roof site surfaces:

   Provide at any combination of the following characteristics for 50% of the site hardscape:

   • Surface is light colored/high albedo (reflectance is .30 or greater.)
   • Surface composed of an open-grid pavement system (less than 50% impervious)
   • 50% of non-parking surfaces will be shaded within 5 years.
   • 50% of parking surfaces will be shaded within 10 years.
   • OR 100% of non-circulation parking surface will be shaded within 10 years.

   OR

   • Place a minimum of 50% of parking spaces underground or in a structured parking facility.
2. Roof Surfaces:
   • Use ENERGY STAR Roof-compliant, high-reflectance AND high emissivity roofing (initial reflectance of at least 0.65 and three-year-aged reflectance of at least 0.5 when tested in accordance with ASTM #903 and emissivity of at least 0.9 when tested in accordance with ASTM 408) for a minimum of 75% of the roof surface.

   OR

   • Install a "green" (vegetated) roof for at least 50% of the roof area.

   OR

   • The two options can be combined by the following formula: (high albedo roof Area/.75) + (green roof area/.5) is greater than or equal to total roof area.