Solar Reflectance Green Roof

Emissivity is a material s ability to release absorbed energy.

Solar reflectance green roof.

The most recent version of leed leed v4 allows either initial or aged sri to be used. Green roofs may not reflect as much as a cool roof but do have other benefits such as evapotranspiration which cools the plants and the immediate area around the plants aiding in lowering rooftop. Green building council usgbc leadership in energy and environmental design leed program uses both reflectance and emittance as expressed in the solar reflectance index sri. 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. Incorporates both solar reflectance and thermal emissivity in a single value. Solar reflectance index sri. The solar reflectance index is used for compliance with leed requirements and is calculated according to astm e 1980 using values for reflectance and emissivity.

Green roofs provide a thermal mass layer which helps reduce the flow of heat into a building. 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. Sustainable roofing glossary albedo.