The Energy Conservation Building Code of 2008 includes a prescriptive requirement for cool roofs in Section 4.3.1.1:  Roofs with slopes less than 20 degrees shall have an initial solar reflectance of no less than 0.70 and an initial emittance no less than 0.75. Solar reflectance shall be determined in accordance with ASTM E903-96 and emittance shall be determined in accordance with ASTM E408-71 (RA 1996).  This national code is become mandatory in some Indian states.