The Solar Reflectance Index (SRI) includes the measure of a material ' s

The Solar Reflectance Index (SRI) is a measure of the roof’s ability to reject solar heat, as shown by a small temperature rise. It is defined so that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100. SRI is calculated using the roof surface’s Solar Reflectance (SR) and Thermal Emittance (TE). SR is the fraction of solar energy that is reflected by the roof, and TE is the relative ability of the roof surface to radiate heat. Therefore, SRI includes the measure of a material’s ability to reflect solar radiation, but not its ability to absorb or emit thermal radiation.

What is the Solar Reflectance Index? - Cool Roof Rating Council

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