After 3 years the solar reflectance must be 0 15.
Roofing with 3 years minimun reflectance.
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.
You can install one with a three year aged solar reflectance index sri of 64 or you can instead opt for one with an aged sri of 55 combined with an aged thermal emittance of 0 75 or.
The energy star program specifies minimum solar reflectance low slope.
If you re following iecc you have a couple of options for roof materials.
0 65 initial 0 50 aged.
A cool roof on residential buildings is defined as one with a 3 year aged solar reflectance of at least 0 20 and an infrared emittance of at least 0 75 or minimum sri of 16 in climate zones 10 through 15 for steep slope applications greater than 2 12 and where the roofing product has a density less than 5 pounds per square foot.
Steep slope roofs must have an initial solar reflectance of 0 25.
Use roofing materials that have an sri equal to or greater than the values in table 1 meet the three year aged sri value if three year aged value information is not available use materials that meet the initial sri value for a minimum of 75 of the roof area of all new buildings within the project or install a vegetated green roof for at least 75 of the roof area of all new buildings within the project.
These shingles must have an initial solar reflectance of at least 0 25 and a three year solar reflectance measurement of at least 0 15.
After 3 years the solar reflectance must be 0 50.
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.
Effective january 1 2010 the standards will require that a cool roof material meet an aged solar reflectance value 3 year testing provided by the cool roof rating council crrc.
Reflectance refers to the roofing material s ability to reflect the energy coming from the sun instead of absorbing it.
Only those roof products that meet the specifications listed in either table 1 or table 2 below may qualify as energy star qualified.
Aged solar reflectance tested in accordance with astm c 1549 astm e 903 or astm e 1918 or crrc 1 standard.
Innate reflectance is measured on a scale from 0 to 1 with the latter being the highest level of reflectivity meaning it reflects 100 of all radiant energy coming in contact with it.
