ASTM D 3361-2020 “Test for Unfiltered Flame Carbon Arc Exposure of 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 sunlight, 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 Caveats – 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 under Section 10 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 1: 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 unfiltered open flame carbon arcs are significantly different from those generated by light and water exposure devices using other carbon arc configurations or other light sources. The type and rate of degradation and performance ranking resulting from exposure to unfiltered open flame carbon arcs may be quite different from those resulting from exposure to other types of laboratory light sources. In general, exposure in accordance with this protocol will produce degradation more rapidly than similar exposure in accordance with practice D822/D822M or D5031/D5031M and may result in different types of degradation.

4.2.2 Inter-laboratory comparisons are valid only if all laboratories use the same type of carbon arc and exposure conditions.

ASTM D 3361-2020 “Test for Unfiltered Flame Carbon Arc Exposure of Paints and Related Coatings”

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. Iv,5 Therefore, it is highly recommended to expose similar materials with known properties (control) 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 in accordance with Practice G152. Important factors include regulation of line voltage, absence of salt or other water deposits, temperature and humidity control, and electrode conditions.

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 specification covers the selection of test conditions for accelerated exposure testing of coatings and related products in unfiltered open-flame carbon arc installations in accordance with regulations G151 and G152. The practice also includes preparation of specimens, suitable test conditions for coatings, and evaluation of test results.

1.2 This practice covers the unfiltered open-flame carbon arc exposure of paints and associated coatings and covers the exposure period commonly referred to as the “dew cycle”. Practice D822/D822M describes the filtered open flame carbon arc device and Practice D5031/D5031M describes the closed carbon arc exposure. Radiation from unfiltered open flame carbon arcs produces shorter wavelengths and higher levels of shortwaver radiation compared to filtered open flame or closed carbon arcs.

ASTM D 3361-2020 “Test for Unfiltered Flame Carbon Arc Exposure of Paints and Related Coatings”

1.3 Values expressed in SI units or inch-pound units should be treated separately as standard values. The values specified in each system are not necessarily the same; Therefore, to ensure compliance with the standards, each system should be used independently of each other and the values of the two systems should not be combined.

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

1.5 This international Standard has been developed in accordance with the 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.

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