ASTM D 6695-2016 “Xenon Arc Exposure Test for Paints and Related Coatings”

Meaning and Purpose
4.1 For many applications, the ability of a paint or coating to resist deterioration of physical and optical properties due to exposure to light, heat, and water may be very important. This practice aims to cause changes in attributes related to end-use conditions, including the effects of daylight, moisture, and heat. The exposures used in this practice are not intended to model the deterioration caused by local weather phenomena such as atmospheric pollution, biological attack, and saline-water exposure.

4.2 Note – Results may change when different operating conditions are used. Therefore, no reference to the use of this practice may be made unless accompanied by a report prepared in accordance with Section 9 describing the specific operating conditions used. See Practice G151 for details of the caveats applicable to the use of the results obtained under this practice.

Note 2: For additional information on sources of variability and strategies to address variability in the design, execution, and data analysis of laboratory accelerated exposure trials, see Guide G141.

4.2.1 The spectral power profiles of light from xenon arcs are significantly different from those produced by light and water exposure devices using carbon arcs or other light sources. The type and rate of degradation and performance rankings produced by exposure to xenon arcs may be quite different from those produced by exposure to other types of laboratory light sources.

ASTM D 6695-2016 “Xenon Arc Exposure Test for Paints and Related Coatings”

4.2.2 Inter-laboratory comparisons are valid only if all laboratories use the same light source, filter type, and exposure conditions.

4.3 The reproducibility of test results between laboratories has been shown to be good when evaluating the stability of the material according to the performance class compared to other materials or controls. 6,7 Therefore, it is highly recommended to expose similar materials with known properties (controls) at the same time as the test material. At least three replications of each material are recommended to allow statistical evaluation of the results.

4.4 Test results will depend on the degree of care with which the equipment is operated according to practice G155. Important factors include regulation of line voltages, absence of salt or other water deposits, temperature and humidity control, and condition and age of lights and filters.

4.5 All exposures referred to in accordance with this practice shall include a complete description of the test period used.

Scope of
1.1 This practice includes the selection of accelerated exposure test conditions for coatings and related products in xenon arc installations according to practices G151 and G155. The practice also includes preparation of specimens, suitable test conditions for coatings, and evaluation of test results.

Note 1: This specification covers the same subject matter as ISO 16474-2, but with different technical content.

1.2SI unit values should be considered standard values. The values given in parentheses are for reference only.

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

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