Low Slope Cool Roof Treatment Sri

Minimum sri values of 78 and 29 for low and steep sloped cool roofs respectivelyiii.

Low slope cool roof treatment sri.

Emissivity is a material s ability to release absorbed energy. Install compliant cool roof material that is listed in the cool roof rating council crrc rated product directory 0 63 aged solar reflectance 0 75 thermal emittance or an sri of 75. In addition the common belief that an average r value is just as good as the code requirements is just that a common belief not a fact. Roof area covered by building integrated photovoltaic panels and solar thermal panels.

Use roofing materials that have an sri equal to or greater than the values in table 1. 3 yr aged solar reflectance min. If aged sri is not available the roofing material shall have an initial sri equal to or greater than the values in table 1. Residential roofing options include asphalt shingles metal clay tiles and concrete tiles.

Cool roof requirements for residential and non residential now apply to low slope and steep slope roofs. Or this sri value roof slope climate zone min. There are different cool roof standards for commercial low slope roofs and residential steep slope roofs. Low slope roofs face the sun on a more consistent and extended period of time than steep slope roofs because they re flatter which is why the reflectance and sri values must be higher to withstand the longer duration of heat from the sun.

Painting a metal roof can increase its solar reflectance and thermal emittance allowing it to achieve cool roof status. Minimum solar reflectance index value by roof slope. Commercial cool roof options include bright white membranes and white coatings. 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.

Department of energy doe has decided to implement cool roofs on all its buildings whenever practicable3. Low slope roof less than 2 12 slope check applicable box below. The ages solar reflectance and thermal emittance requirements will vary depending on the slope of the roof climate zone and the density of the roofing product. The doe uses the low sloped cool roof definition from table 1 and defines steep sloped cool roofs as those with a 3 year aged sri of 29 or greater.

Alternatively you can apply cool reflective coatings. Low slope roofs require an initial sr value of 0 65 or higher and 0 50 or greater after three year. Wrapping it all up. How they can be made cool.