ASTM D772-18

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.
Designation: D772 − 18
Standard Test Method for
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Evaluating Degree of Flaking (Scaling) of Exterior Paints
This standard is issued under the fixed designation D772; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 3. Terminology
1.1 This test method covers the evaluation of the degree of 3.1 Definitions of Terms Specific to This Standard:
flaking (scaling) of exterior paints by comparison with photo- 3.1.1 flaking, n—that phenomenon manifested in paint films
graphic standards. by the actual detachment of pieces of the film itself either from
its substrate or from paint previously applied. In this standard,
1.2 The values stated in SI units are to be regarded as the
the terms flaking and scaling are considered synonymous.
standard. The values given in parentheses are for information
Refer to 6.2.3.
only.
3.1.1.1 Discussion—Flaking is generally preceded by crack-
1.3 This test method is similar though not identical to ISO
ing or checking or blistering, and is the result of loss of
4628 Part 5. ISO 4628 Part 5 usesa0to5 rating scale, where
adhesion, usually due to stress-strain factors coming into play.
a rating of 0 is no change and a rating of 5 is most severe. Test
Method D772 uses a 10 to 0 rating scale, where a rating of 10 4. Significance and Use
isnochangeandaratingof0ismostsevere.Thetwostandards
4.1 Flaking failure of paint films can occur in use. This test
use different pictorial reference photographs for determining
method provides a means of evaluating the degree of failure by
the rating values.
comparing to pictorial standards.
1.4 This standard does not purport to address all of the
5. Type of Flaking
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.1 Only one type of flaking is recognized, as defined in
priate safety, health, and environmental practices and deter-
Section 3.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor- 6. Use of Photographic Reference Standards
dance with internationally recognized principles on standard-
6.1 The photographic reference standards that are part of
ization established in the Decision on Principles for the
this test method are representative of the degree of flaking of
Development of International Standards, Guides and Recom-
exterior paint films.
mendations issued by the World Trade Organization Technical
6.2 The use of the photographic reference standards illus-
Barriers to Trade (TBT) Committee.
trated in Figs. 1-4 requires the following precautions:
6.2.1 Care must be taken not to confuse various types of
2. Referenced Documents
failure that may be present on the same surface.
2
2.1 Other Standards:
6.2.2 It must be realized that degree of failure will vary over
ISO 4628 Part 5—Paints and Varnishes—Evaluating the
any given area. Therefore, an average portion of the film
Degradation of Coatings—Designation of Quantity and
should be used for comparison. On larger surfaces it is
Size of Defects, and of Intensity of Uniform Changes in
recommended that ratings be made at several locations and the
Appearance—Part 5: Assessment of Degree of Flaking
mean and range reported.
6.2.3 In technical literature, a distinction is sometimes made
between flaking and scaling. In most cases, however, flaking
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This test method is under the jurisdiction of ASTM Committee D01 on Paint
and scaling refer to the same phenomenon. In some instances,
and Related Coatings, Materials, andApplications and is the direct responsibility of
the term flaking is used to describe the detachment of pieces of
Subcommittee D01.25 on Evaluation of Weathering Effects.
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film less than 6.4 mm ( ⁄4 in.) in size, and scaling, the
Current edition approved Sept. 1, 2018. Published October 2018. Originally
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approved in 1944. Last previous edition approved in 2011 as D772 – 86 (2011).
detachment of pieces over 6.4 mm ( ⁄4 in.) in size. In other
DOI: 10.1520/D0772-86R18.
instances, the term flaking is used to describe the detachment
2
Available from U.S. National Committee of the CIE (International Commission
of pieces of film from the immediate undercoat (intercoat
on Illumination), C/o Alan Laird Lewis, 282 E. Riding, Carlisle, MA 01741,
http://www.cie-usnc.org. failure) and scaling the detachment of pieces from the base
*A
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