Meaning and use
5.1 This test method is designed to induce color changes in sealants and their component pigments related to the conditions of end use, including the effects of sunlight, moisture and heat. The exposures used in this test method are not intended to simulate color changes in sealants caused by local weathering phenomena, such as atmospheric pollution, biological attack, and saline exposure.

5.2 When performing exposure in equipment using laboratory light sources, it is important to consider how the manual test conditions will reproduce the performance variations and failure modes associated with the final use environment of the sealant under test. Information on the use and interpretation of accelerated exposure test data is provided in Practice G151.

5.3 When this test method is used as part of the specification, the exact procedure, test conditions, test duration and evaluation techniques need to be specified. Due to the different spectral power distribution of the light sources (fluorescent ultraviolet and xenon arc), the results obtained between the two procedures may differ. Sealants should not be compared to each other based on results obtained in different types of equipment.

5.4 These devices are well matched to ultraviolet solar radiation. However, for sealants that are sensitive to long wavelength ultraviolet and visible solar radiation, the absence of such radiation in fluorescent ultraviolet devices will distort the color stability ranking compared to external environmental exposure.

Note 1: For a complete cautionary guide on laboratory ageing of non-metallic materials, see Practice G151.

ASTM C1501-2019 Standard Test Method for Evaluating Color Fastness of Building Structural Sealants by Laboratory Accelerated Aging Procedures

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1.1 This test method describes laboratory accelerated aging procedures for the determination of color stability of building construction sealants using fluorescent ultraviolet or xenon arc test devices.

1.2 The color stability rankings provided by these two programs may not be consistent.

1.3 Values expressed in SI units shall be considered standard. The values given in parentheses are for reference only.

1.4 There is no equivalent ISO standard for this test method.

1.5 This standard is not intended to address all safety concerns, if any, associated with its use. It is the responsibility of users of this standard to establish appropriate safety, health and environmental practices and to determine the applicability of regulatory restrictions prior to use.

1.6 This international standard is based on internationally recognized standardization principles established in the Decision on Principles for the Development of International Standards, Guidelines and Recommendations issued by the Committee on Technical Barriers to Trade of the World Trade Organization.