Sri Value Of Roofing Materials

A value of 0 indicates that the material absorbs all solar energy and a value of 1 0 indicates total reflectance.

Sri value of roofing materials. The higher the value the more heat the material emits. Energy star requires an initial sr value of 0 25 or higher for steep slope 2 12 roofs and 0 15 or greater after three years. 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. Asphalt coatings for example have aluminum pigments added to asphalt cutbacks and emulsions to give coatings solar reflectance index sri values of 21 30 on a scale of 0 100.

Sri measures the roof s ability to reject solar heat defined such that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is 100. Nb this definition means that it is possible to have materials with an sri of less than 0 or more than 100. The solar reflectance index or sri is a calculation using the aged solar reflectance and thermal emittance measurements of the asphalt shingles materials. Ref cool roof rating council solar reflectance index calculation worksheet.

The higher the sri the cooler the roof will be. This measure is calculated from the tsr and te. This measurement can be used as an indicator of how hot shingles are likely to become when they re exposed to the sun. Different roofing technologies have different sri values.

Solar reflectance index sri. Sri can be calculated based on the pitch of a roof its weight its solar reflectance thermal emittance emissivity and its ageing characteristics. The sr value is a number from 0 to 1 0. Low slope roofs require an initial sr value of 0 65 or higher and 0 50 or greater after three year.

The third metric used to measure the performance of cool roof coverings is called the solar reflectance index sri. Incorporates both solar reflectance and thermal emissivity in a single value. Recycled content of berridge metal. It ranges from 0 to 100.