New Process to Test Cool Roofing Performance

While reflective roofing materials can keep the inside of facilities cool and help mitigate the urban heat island effect, their performance can significantly diminish as the materials age and become soiled. A new test designed by scientists at the Lawrence Berkeley National Laboratory simulates the soiling and weathering process of three years in just a few days, allowing new materials to be more quickly vetted for performance in the elements. 

The process involves placing the roofing material inside of a weathering apparatus, a soiling device, and back to the weathering apparatus, which simulates three years of exposure to the elements. The testing method was applied to 25 different roof products including single-ply membranes, coatings, tiles, and asphalt shingles. Additionally, the researchers used different soiling mixtures to mimic the specific features of different geographic areas, including a hot and humid climate, a hot and dry climate, and a polluted atmosphere in a temperate climate.

The protocol has been accepted by ASTM International as a standard practice for the industry and published as ASTM D7897-15. The new standard has been accepted by the Cool Roof Rating Council and will consequently meet the standards for California’s Title 24 Building Energy Efficiency Standards.