Metal roofing painted with a coating made with Kynar 500® PVDF can achieve solar reflectance of over 70%. Reflected solar energy allows the roof surface to remain cooler, which means less heat is transferred into the building. Cool metal roofing coated with a coating made with Kynar 500® PVDF resin is one way to limit the urban heat island effect.
Urban Heat Island - a built environment where the large portion of dark absorbing surfaces such as asphalt paving and dark roof tops trap solar energy and radiate the energy back into the atmosphere. Such areas typically have less vegetation than the surroundings. Urban heat islands can have an air temperature that is 6-12°F higher than the rural suburbs.
One way to measure how "cool" is a roof can be with a term called solar reflectance index (SRI). This unitless index is calculated using the solar reflectance value, the thermal emittance value, and a wind coefficient. The SRI calculation can also be used to estimate the surface temperature of the roof product under prescribed conditions. The method for calculating SRI is defined in ASTM E1980-01. Materials with the highest SRI values are the coolest choices for roofing.
A simple SRI calculator can be downloaded using the link below. To calculate SRI, enter the measured solar reflectance value as a decimal, the measured thermal emittance value as a decimal, then click on "Calculate".
Produced without the use of Fluorinated Surfactants
Arkema produces Kynar 500® PVDF resin using a patented process. This means that no fluorosurfactant of any kind is used. Some foreign PVDF producers for the coatings market (who export to the USA and Europe) still reportedly use fluorosurfactants. It is important for PVDF coating consumers to understand what they are using.
FAQ - Cool metal roof coatings made with Kynar 500® PVDF
Visit our FAQs page to learn about coatings made with Kynar 500® PVDF for roofing. Discover why coatings made with Kynar 500® PVDF are the best choice for cool roofing.