D7990, Test Method for Using Reflectance Spectra to Produce an Index of Temperature Rise in Polymeric Siding will help evaluate potential for elevated temperature in plastic siding based on color. Standard produces index of relative degree of heat absorption of color system, which is a non-dimensional intensity factor. Specifically, test method uses reflectance spectra from UV, visible, and near-IR rays to create index of temperature rise that occurs due to siding absorbing sun’s energy.