Solar Reflectance Index Green Roof

Installing a cool roof can cut your energy costs while contributing toward a better environment.

Solar reflectance index green roof.

Requirements and is calculated according to astm e 1980 using values for reflectance and emissivity. These demanding standards call for air conditioned non residential buildings with low slope roofs to have a roof surface that has 70 initial solar reflectivity and a 75 initial infrared emittance as measured by the crrc. Sustainable roofing glossary albedo. The solar reflectance index can be used in cool roof calculations to demonstrate compliance with leed leadership in energy and environmental design a voluntary environmental certification system developed by the u s.

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 guide to choosing a cool roof. California s building energy efficiency standards for residential and nonresidential buildings title 24 part 6 contains requirements for the thermal emittance three year aged reflectance and solar reflectance index sri of roofing materials used in new construction and re roofing projects. Solar reflective index sri is important to understand when selecting a highly reflective roof coating that will help lower energy cooling costs.

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. Albedo or solar reflectance is a measure of a material s ability to reflect sunlight including the visible infrared and ultraviolet wavelengths on a scale of 0 to 1 an albedo of 0 0 indicates that the surface absorbs all solar radiation and an albedo of 1 0 represents total reflectivity. When planning improvements or repairs to your roof consider these green upgrades that could further your competitiveness for leed certification. Recycled content of berridge metal.

Solar reflectance index sri. Furthermore it doesn t store as much thermal energy as an ordinary roof. Emissivity is a material s ability to release absorbed energy. The sri is a calculation method using solar reflectance and thermal emittance values to determine the roof s overall capacity to refuse solar heat.

Incorporates both solar reflectance and thermal emissivity in a single value. Heat island effect 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. Fibertite roofing membranes meet the sr and ie requirements of california title 24 energy efficiency standards.

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.