1.1 This test method covers liquid-applied coatings used in roofing systems as the final roof surface that confers the additional benefit of reducing the amount of solar energy absorbed by the roofing system. 1.2 This test method provides an accelerated laboratory method of comparing the relative retention of particulates when these materials are exposed to typical of environmental fallout from the atmosphere during their normal use. 1.3 The particulate matter that deposits on a roofing surface is known to vary regionally and, over time, may involve complex chemical reactions the specifics of which are beyond the scope of this test method. 1.4 This test method measures the reduction of lightness or solar reflectivity or both caused by the collection of particulate matter that binds onto the surface and that is not anticipated to be removed by normal cycles of rain. 1.5 The effect of biological growth on the reduction in lightness or solar reflectivity or both of the surface are not determined by this test method. 1.71.6 SI units are used throughout this standard. US units are in parentheses. 1.81.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
The proposed test method is intended to provide a practical means of rating a key cool roofing performance parameter: dirt pickup resistance. While a perfect simulation may not be possible, in the coatings arena, a consensus approach emerged alongside of an improved understanding of what materials collect on roofs that we believe supports a laboratory scale test useful to the improvement of roofing materials.
dirt pickup; particulate matter; liquid-applied coating; light-colored
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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