Solar Reflectance Of Roofing Materials

The solar reflectance index is used for compliance with leed.

Solar reflectance of roofing materials. All roofing products must be certified and labeled according to the cool roof rating council crrc to comply with the standards. Asphalt shingles with higher solar reflectance values can achieve energy star certification. The solar reflectance index sri is a measure of the constructed surface s ability to reflect solar heat as shown by a small temperature rise. The more waves that are bounced back into the atmosphere the higher the solar reflectance of the asphalt roofing shingle.

Solar reflectance and thermal emittance are the two key material surface properties that determine a roof s temperature and they each range on a scale from 0 to 1. The solar reflectance measurement ranges between 0 0 and 1 0 with 1 0 representing 100 reflectance with no absorption. Heat island effect roof. The attic under the roof.

To meet leed requirements a roofing material must have a sri of 29 or higher for steep slope 2 12 roofing and a sri value of 78 or higher for low slope roofing. Emissivity is a material s ability to release absorbed energy. The larger these two values are the cooler the roof will remain in the sun. Requirements and is calculated according to astm e 1980 using values for reflectance and emissivity.