ASTM D4141/D4141M-22

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4141/D4141M − 14 D4141/D4141M − 22
Standard Practice for
Conducting Black Box and Solar Concentrating Exposures
of Coatings
This standard is issued under the fixed designation D4141/D4141M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice covers two accelerated outdoor exposure procedures for evaluating the exterior weather resistance of coatings
applied to substrates.
1.2 The two procedures are as follows:
1.2.1 Procedure A—Black Box Exposure.
1.2.2 Procedure C—Fresnel Reflector Rack Exposure.
NOTE 1—Procedure B described a Heated Black Box procedure that is no longer in common use.use and has been removed as of the 2014 revision of
this standard.
1.3 This standard does not cover all the procedures that are available to the user for accelerating the outdoor exposure of coatings.
Other procedures have been used in order to provide a particular effect; however, the two procedures described here are widely
used.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
This practice is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.27 on Accelerated Testing.
Current edition approved Feb. 1, 2014Jan. 1, 2022. Published February 2014January 2022. Originally approved in 1982. Last previous edition approved in 20072014 as
D4141 – 07.D4141/D4141M – 14. DOI: 10.1520/D4141/D4141M-14.10.1520/D4141_D4141M-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4141/D4141M − 22
D523 Test Method for Specular Gloss
D660 Test Method for Evaluating Degree of Checking of Exterior Paints
D661 Test Method for Evaluating Degree of Cracking of Exterior Paints
D662 Test Method for Evaluating Degree of Erosion of Exterior Paints
D714 Test Method for Evaluating Degree of Blistering of Paints
D772 Test Method for Evaluating Degree of Flaking (Scaling) of Exterior Paints
D823 Practices for Producing Films of Uniform Thickness of Paint, Coatings and Related Products on Test Panels
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
D4214 Test Methods for Evaluating the Degree of Chalking of Exterior Paint Films
D7091 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals
and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals
E772 Terminology of Solar Energy Conversion
G7 Practice for Natural Weathering of Materials
G90 Practice for Performing Accelerated Outdoor Weathering of Materials Using Concentrated Natural Sunlight
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G141 Guide for Addressing Variability in Exposure Testing of Nonmetallic Materials
G147 Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests
G169 Guide for Application of Basic Statistical Methods to Weathering Tests
3. Terminology
3.1 The definitions given in TerminologyTerminologies G113 and E772 are applicable to this practice.
4. Summary of Practice
4.1 SeveralTwo procedures are described that provide acceleration of the degradation that coatings evidence during natural
weathering when exposed on an open rack at a fixed angle. The procedures appear in the following order:
4.1.1 Procedure A—Exposure on a black box rack facing tilted toward the equator at 5° from the horizontal.
4.1.2 Procedure C—Exposure on a Fresnel reflector rack that provides a high irradiance by following the sun sun’s daily path and
concentrating sunlight radiation from the sun on the test specimens by means of mirrors. The specimens are wet periodically by
high purity high-purity water spray.
4.2 The selection of Procedure A or C is dependent on several factors.
4.2.1 Procedure A is designed to simulate the weathering that occurs on horizontal insulated surfaces. surfaces, such as exterior
automotive coatings. Specimens are typically flat-coated metal panels measuring 10 by 30 cm [4 by 12 in.] or 15 by 30 cm [6 by
12 in.].
NOTE 2—Procedure A is specified in standards used by the automotive industry.
4.2.2 Procedure C is designed to simulate weathering on both automotive and nonautomotive products.any application of exterior
coatings. Procedure C typically provides faster results than Procedure A on a calendar basis.
5. Significance and Use
5.1 As with any accelerated test, the increase in rate of weathering compared to in service in-service exposure is material
dependent. Therefore, no single acceleration factor can be used to relate two different types of outdoor weathering exposures. The
weather resistance rankings of coatings provided by these two procedures may not agree when coatings differing in composition
are compared. These two procedures should not be used interchangeably.
5.2 The procedures described in this practice are designed to provide greater degradation rates of coatings than those provided by
Zerlaut, G.A., Rupp, M.W., and Anderson, T.E., “Ultraviolet Radiation as a Timing Technique for Outdoor Weathering of Materials,” Paper 850378, Proceedings, SAE
International Congress, Detroit, February 25, 1985.
D4141/D4141M − 22
fixed angle open-rack fixed-angle, open-rack, outdoor exposure racks. For many products, fixed angle exposures will produce
higher degradation rates than the normal end use of the material.
5.2.1 The use of Procedure A (Black Box) instead of an open-rack direct exposure is a more realistic test for materials with higher
temperature end use service conditions. For many coatings, this procedure provides greater rates of degradation than those
provided by 5°, equator-facing, open-rack exposures because the black box produces higher specimen temperatures during
irradiation by daylight and longer time of specimen wetness. The black box specimen temperatures are comparable to those
encountered on the hoods, roofs, and deck lids of automobiles parked in sunlight. The relative rates of gloss loss and color change
produced in some automotive coatings by exposures in accordance with Procedure A are given in ASTM STP 781.
5.2.2 The acceleration of degradation by weathering as described in Procedure C is produced by reflecting sunlight from ten
mirrors onto an air-cooled specimen area. In the ultraviolet portion of the solar spectrum, approximately Approximately 1400
MJ/m of ultraviolet radiant exposure (295 to 385 nm) 385 nm) is received over a typical one-year period when samples are
exposed on these devices are operated in a central Arizona climate. This compares with approximately 333 MJ/m of ultraviolet
radiant exposure from a central Arizona at-latitude exposure and 280 280 MJ MJ/m⁄m of ultraviolet radiant exposure from a
southern Florida at-latitude exposure over the samean equivalent time period. However, the test described by Procedure C reflects
only direct beam radiation onto test specimens. The reflected direct beam of sunlight contains a lower percentage of short
wavelength ultraviolet radiation than global daylight because short wavelength ultraviolet is more easily scattered by the
atmosphere, and because mirrors are typically less efficient at shorter ultraviolet wavelengths. Ultraviolet radiant exposure levels
should not be used to compute acceleration factors since acceleration is material dependent.
5.3 The weather resistance of coatings in outdoor use can be very different depending on the geographic location of the exposure
because of differences in ultraviolet (UV) radiation, time of wetness, temperature, pollutants, and other factors. Therefore, it cannot
be assumed that results from one exposure in a single location will be useful for determining relative weather resistance in a
different location. Exposures in several locations with different climates that represent a broad range of anticipated service
conditions are recommended.recommended to determine weathering resistance and/or service life.
5.4 Because of year-to-year climatological variations, results from a single exposure test cannot be used to predict the absolute
rate at which a material degrades.
NOTE 3—Several Three or more years of repeat exposures exposures, starting at various times of the year, are typically needed to get an “average” test
result for a given location.
5.4.1 The degradation profile for many polymerscoatings is not a linear function of exposure time or radiant exposure. When short
exposures are used as indications of weather resistance, the results obtained may not be representative of those from longer
exposures.
NOTE 4—Guide G141 provides information for addressing variability in exposure testing of nonmetallic materials. Guide G169 provides information for
applying statistics to exposure test results.
NOTE 4—Guide G141 provides information for addressing variability in exposure testing of nonmetallic materials. Guide G169 provides information for
applying statistics to exposure test results.
5.5 It is recommended that at least one control material be part of any exposure evaluation. Control materials are used for
comparing the performance of the test materials relative to the controls when materials are not being ranked against one another.
The control material used should be of similar composition and construction to the test materials and be of known weather
resistance. It is preferable to use two control materials, one with relatively good weather resistance and one with poor weather
resistance.
6. Test Specimens
6.1 Each test specimen and control specimen shall consist of a uniform coating applied to the surface of a flat panel because
warpage, waviness, or curvature may seriously affect the measurement of gloss and color. Flat, rigid specimens are preferred.
Non-rigid specimens shall be backed to ensure a proper seal on the black box rack (Procedure A), or to ensure proper cooling
(Procedure C). Suitable application procedures are given in Prac
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