The State of Minnesota
Sustainable Building Guidelines (MSBG) Version 2.0

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
A. 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.

B. 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.

Note: Portions of this guideline are adapted from LEED Version 2.0 and Version 2.2.