ASTM E3165-18 PDF Download

ASTM E3165-18 is a standard test method that outlines the procedure for determining the nighttime retroreflected chromaticity of retroreflective sheeting. The results of this test method are used to evaluate whether the retroreflective sheeting complies with nighttime color requirements set by industry standards and government regulations. Specifications such as Specification D4956 and U.S. Code of Federal Regulations Title 23 Part 655 Subpart F reference this test method for assessing chromaticity.

The requirements stated in specifications utilizing this test method pertain to the chromaticity of the retroreflective material as observed at night. These requirements are usually defined using four or five corner points that form a bounding box, within which the acceptable range of chromaticity must fall. These specifications are categorical in nature and specify a limited range of colors that are distinguishable for color naming or coding purposes.

The compliance with the specification is determined by plotting the measured (x, y) values of the retroreflective sheeting and checking if the measured point falls within the specification's chromaticity box for the specific color of interest.

The test method employs tristimulus filter colorimetry and spectral measurements to determine the chromaticity coordinates of the retroreflective sheeting. The chromaticity coordinates generated using this method are intended for use with the CIE 1931 chromaticity system and CIE Illuminant A. If measurements and calculations are required for different sources of illumination, geometries, or other materials, users are directed to refer to the general practice described in ASTM Practice E811.