ID#5220 made on
SSc7.1 - Heat island effect - nonroof
LEED BD+C: New Construction, LEED BD+C: Schools, LEED BD+C: Core and Shell, LEED O+M: Existing Buildings
The intent of this credit is to "Reduce heat islands to minimize impact on micro-climate and human and wildlife habitat." The requirements for the credit call for providing any combination o...
The intent of this credit is to "Reduce heat islands to minimize impact on micro-climate and human and wildlife habitat." The requirements for the credit call for providing any combination of strategies for 50% of the site hardscape. Our project will implement the strategy of using paving materials with an SRI of at least 29. While some of the asphalt areas are shaded within 5 years of occupancy, our proposal aims to achieve the credit using only the SRI-compliant paving strategy. Our project is a major league ballpark in downtown Minneapolis, MN. The LEED project boundary includes the ballpark, the surrounding concrete plaza/walkway areas and an asphalt surface parking lot with shade vegetation and shade from overhead ramps. The total area of hardscaped parking lot, walkways and plaza is 337,456 SF. To comply with the credit requirements, a minimum of 50% or 168,728 SF must have an SRI of 29 or greater. A CIR dated 6/19/2008 for related credit SSc7.2 Heat Island Effect - Roof allowed the use of a weighted average formula where multiple roofing materials were used, such that the total roof area weighted average SRI exceeded the required SRI. Similarly, our project's concrete plaza combines standard gray concrete and multiple concrete paver colors into a pattern. While the majority of the pattern is a concrete color with an SRI of 52, a smaller portion of the pattern is a concrete color with an SRI of 12. The parking lot is asphalt pavement, some of which is shaded, but for the purpose of this calculation, we have considered all asphalt to have an SRI of 0. Using the formula for weighted average per the above CIR, we propose performing a similar calculation for each color of all site hardscape to arrive at a weighted average, as follows: [(Area of Asphalt *(SRI of Asphalt/Required SRI)) + (Area of Std. Concrete*(SRI of Std. Concrete/Required SRI) )+ (Area of Concrete Paver 1*(SRI of Concrete Paver 1/Required SRI)) + (Area of Concrete Paver 2*(SRI of Concrete Paver 2 /Required SRI)) + (Area of Concrete Paver 3*(SRI of Concrete Paver 3 /Required SRI))] >= .50 Site Hardscape Area So our calculation would be [(180,672*0/29) + (31,032*35/29) + (97,869*52/29) + (27,883*12/29) = 224,479 which exceeds the 168,728 SF (or 50%) total hardscape requirement. Will this formula be acceptable for SSc7.1 credit compliance?
The project team is proposing a weighted average approach to achieving SSc7.1 similar to the weighted average approach used for alternative compliance to SSc7.2 Heat Island Effect Roof. The proposed methodology for achieving SSc7.1 is acceptable. Be sure to provide all relevant submittal documentation including site plans with areas highlighted and area takeoffs as well as documentation of the measured reflectance and emittance for each material. Please be advised that any areas of hardscape counted within the weighted SRI calculation cannot be used within a shaded area calculation. Applicable Internationally.
Related Addenda (Corrections & Interpretations)