Rating System

LEED BD+C: New Construction, LEED O+M: Existing Buildings, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v3 - LEED 2008, v2 - Schools 2007, v2 - LEED 2.2

Inquiry

Our project is a three story laboratory facility in the city of Port St. Lucie Florida. The project has used an exterior coating system with a higher heat reflectance value than the values of conventional coatings. This credit interpretation request is to inquire about submitting the coating system used, to apply for a credit for reduced heat island effect for non-roof surfaces. The Total Solar Reflectance (TSR) values of the exterior coatings used in the building were tested using a D&S reflectometer according to ASTM C1549-04. The TSR value of the BML-01 "White" color used was 82.9% and the TSR value for the PPG522-3 "Water Chestnut" color used was 74.5%. To prove merit for one point under LEED, we have followed the guidelines of the LEED reference guide to document Sustainable Sites Credit 7.1-Heat island effect non-roof. The baseline case and design case were calculated using the exterior wall surface area and 50% of the site hardscape area. The baseline case was calculated using 43.7% solar reflectance for conventional beige paint to match the color used in the building and 35% for new gray concrete hardscape. The design case was calculated using 74.5% solar reflectance for the Water Chestnut coating used and 5% for new asphalt hardscape. Using Ecotect and site specific data the building was modeled with the correct north orientation. Ecotect calculated the incident solar radiation that strikes the north, south, east and west walls, and the hardscape surfaces annually in Wh. The incident solar radiation value for the four facades and the hardscape were added, and multiplied by the solar reflectance values to determine the site reflected solar energy. The analysis showed that 61% of solar energy would have been reflected using conventional paint and new gray concrete, but instead we are reflecting 77% of the total solar energy incident on the site using a coating with a higher heat reflectance value. We would like to know if this approach of using exterior coatings with higher reflectance values to lower heat island effect on non-roof surfaces will be acceptable to document one innovation in design point.