Rashid, you will need documentation showing that the paint or whatever else you apply is actually high SRI. You can't simply claim the credit by using a white color, since SRI values vary so much even with materials that may appear to be simlar colors. Also, keep in mind that SRI factors in emissivity which is different than reflectivity. Polished aluminum, for example, is highly reflective but very poorly emissive.
Thanks tristan for your comments. In case if we couldn't find a coating which has data sheets to show compliance of that having a suitable SRI will it be sufficient if we check a sample with lab and show the compliance or does our test has to be done to a sample of the roof material which is after applying the paint..please post your comments.