Solar Reflectance Of Roofing Materials

It is defined so that a standard black surface reflectance 0 05 emittance 0 90 is 0 and a standard white surface reflectance 0 80 emittance 0 90 is 100.

Solar reflectance of roofing materials.

Solar reflective shingles are designed specifically to reduce the absorption of the suns infrared radiation by reflecting ir rays off the surface of the roof thus not allowing the heat to be transferred to the interior of the structure i e. The more waves that are bounced back into the atmosphere the higher the solar reflectance of the asphalt roofing shingle. The attic under the roof. Heat island effect roof.

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. 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. Asphalt shingles with higher solar reflectance values can achieve energy star certification. The solar reflectance measurement ranges between 0 0 and 1 0 with 1 0 representing 100 reflectance with no absorption.

All roofing products must be certified and labeled according to the cool roof rating council crrc to comply with the standards. 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. The solar reflectance index is used for compliance with leed. The larger these two values are the cooler the roof will remain in the sun.