ASTM E1918-21

1.1 This test method covers the measurement of solar reflectance of various horizontal and low-sloped surfaces and materials in the field, using an albedometer or pyranometer. The test method is intended for use when the sun angle to the normal from a surface is less than 45°.

1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 Solar reflectance is an important factor affecting the temperature of a sunlit surface and that of the near-surface ambient air temperature. The test method described herein measures the solar reflectance of surfaces in natural sunlight.