ASTM D772-2018 Standard Test Method for Evaluating Degree of Flaking (Scaling) of Exterior Paints.pdf

1、Designation: D772 86 (Reapproved 2011)D772 18Standard Test Method forEvaluating Degree of Flaking (Scaling) of Exterior Paints1This standard is issued under the fixed designation D772; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision

2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript 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 Scope*1.1 This test m

3、ethod covers the evaluation of the degree of flaking (scaling) of exterior paints by comparison with photographicstandards.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This test method is similar though not identic

4、al to ISO 4628 Part 5. ISO 4628 Part 5 uses a 0 to 5 rating scale, where a ratingof 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 is no changeand a rating of 0 is most severe. The two standards use different pictorial reference ph

5、otographs for determining the rating values.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine

6、theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued

7、by the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1150 Single and Multi-Panel Forms for Recording Results of Exposure Tests of Paints (Withdrawn 1992)32.1 Other Standards:2Pictorial Standards of Coating Defects HandbookISO 4628 Pa

8、rt 5Paints and VarnishesEvaluating the Degradation ofCoatingsDesignation of Quantity and Size of Defects, and of Intensity of Uniform Changes in AppearancePart 5:Assessment of Degree of Flaking3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 flaking (scaling), flaking, nthat ph

9、enomenon manifested in paint films by the actual detachment of pieces of the filmitself either from its substrate or from paint previously applied. In this standard, the terms flaking and scaling are consideredsynonymous. Refer to 6.2.3.3.1.1.1 DiscussionFlaking (scaling) is generally preceded by cr

10、acking or checking or blistering, and is the result of loss of adhesion, usually due tostress-strain factors coming into play.1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee

11、D01.25 on Evaluation of Weathering Effects.Current edition approved Nov. 1, 2011Sept. 1, 2018. Published November 2011October 2018. Originally approved in 1944. Last previous edition approved in 20052011as D772 86 (2005).(2011). DOI: 10.1520/D0772-86R11.10.1520/D0772-86R18.2 For referenced ASTM stan

12、dards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Available from U.S. NationalCommittee Annual Book of ASTM Standardsof volume information, refer to the standards Document Summary page on the ASTM website.the CIE (InternationalCommission on Illumin

13、ation), C/o Alan Laird Lewis, 282 E. Riding, Carlisle, MA 01741, http:/www.cie-usnc.org.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. Becauseit may not be technically possible t

14、o adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright

15、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 Flaking (scaling) failure of paint films can occur in use.This test method provides a means of evaluating the degree of failureby comparing to pictorial standards.5. Ty

16、pe of Flaking (Scaling)5.1 Only one type of flaking (scaling) is recognized, as defined in Section 3.6. Use of Photographic Reference Standards6.1 The photographic reference standards that are part of this test method and are provided in the are Pictorial Standards ofCoating Defects Handbook are rep

17、resentative of the degree of crackingflaking of exterior paint films.Fig. 1 is for illustrationpurposes only and should not be used for evaluation.6.2 The use of the photographic reference standards illustrated in Fig. 1Figs. 1-4 requires the following precautions:6.2.1 Care must be taken not to con

18、fuse various types of failure that may be present on the same surface.6.2.2 It must be realized that degree of failure will vary over any given area. Therefore, an average portion of the film shouldbe used for comparison. On larger surfaces it is recommended that ratings be made at several locations

19、 and the mean and rangereported.6.2.3 In technical literature, a distinction is sometimes made between flaking and scaling. In most cases, however, flaking andscaling refer to the same phenomenon. In some instances, the term flaking is used to describe the detachment of pieces of film lessthan 6.4 m

20、m (14 in.) in size, and scaling, the detachment of pieces over 6.4 mm (14 in.in.) in size. In other instances, the termflaking is used to describe the detachment of pieces of film from the immediate undercoat (intercoat failure) and scaling thedetachment of pieces from the base (complete failure). I

21、t should be kept in mind that the flakes may vary widely in size and shapefrom those illustrated by the reference standards in Fig. 1Figs. 1-4, varying from a fraction of an inch to several inches in size.D772 1824 Copies of the pictorial photographic reference standards are contained in the publica

22、tion Pictorial Standards of Coatings Defects and may be obtained from the Federationof Societies for Coatings Technology, 492 Norristown Rd., Blue Bell, PA19422. The silver halide-gelatin photographs are intended to be the only primary reference standardsfor this method. The reproductions of them in

23、 this test method are for the purpose of illustration only.FIG. 1 #2 Rating for FlakingD772 183FIG. 12 Degrees of Flaking (Scaling)#4 Rating for FlakingD772 184FIG. 13 Degrees of Flaking (Scaling) #6 Rating for Flaking (continued)D772 185FIG. 4 #8 Rating for FlakingD772 1866.2.4 PeelingFlaking is fr

24、equently due to a moisture condition and when this is evident it should be taken into consideration inany evaluation.6.2.5 For convenience in recording the data obtained, the records may be kept on forms such as Standard D1150.57. Test Specimens7.1 If the specimen is small enough to be picked up, ra

25、te the entire specimen. If inspecting a larger specimen, use a samplingplan agreed to by interested parties. The sampling plan, if used, shall be included in the report.8. Procedure8.1 View the specimen under the best possible lighting conditions. If the inspection is performed outdoors, use direct

26、sunlightwhere possible. If the inspection is performed indoors, use daylight lamps, or use lighting agreed to by interested parties.8.2 If the specimen can be picked up, move the specimen around to view it from different angles. If the specimen cannot bepicked up, move around the specimen to see it

27、from different viewing angles.8.3 Compare the test specimen or evaluated area of any exposed surface to the visual reference standards under either outdooror indoor illumination. If one of the failure modes appears to be flaking, assign the flaking a numerical rating that corresponds mostsimilar to

28、that in the pictorial references. The flaking numerical rating assigned will have a minimum rating of 0 and a maximumrating of 10. If the evaluated area has no flaking, assign a numerical rating of 10 to this specimen or evaluated area. If the evaluatedarea has most or all of the coating missing, as

29、sign a numerical rating of 0 to this specimen or evaluated area. Original versionsof the reference photographs are available from ASTM as an adjunct.8.4 If the severity of flaking falls between two reference standards, assign an intermediate (odd-numbered) rating. The ratingshould be given as a whol

30、e number.8.5 Do not use magnification, except to verify the type of effect seen8.6 Record the results on the report form as noted in Section 9.9. Report9.1 Report the following items:9.1.1 Specimen description,9.1.2 Flaking rating,9.1.3 Date of the inspection,9.1.4 Technician initials that performed

31、 the inspection,9.1.5 If applicable, any sampling plan that was used.10. Precision and Bias10.1 No precision or bias statement has been established for this test method.Visual evaluation and rating of weathering effectson exposed surfaces is highly subjective. The use of photographs or drawings to r

32、ate specimens or objects by comparison is usedto reduce the variability by providing a known reference.10.2 Round robin testing conducted in June of 2016 indicates that even though this is a subjective test method, multiple trainedoperators within the same location will typically agree on the rating

33、 of a single specimen within plus or minus one flaking ratingunit.10.3 Because of the possibility of bias in which certain operators rate specimens higher or lower than other operators, intralabcomparative evaluation is highly recommended.11. Keywords11.1 evaluations; flaking; reference standards; s

34、calingD772 187SUMMARY OF CHANGESCommittee D01 has identified the location of selected changes to this standard since the last issue(D772-86(2011) that may impact the use of this standard. (Approved September 1, 2018.)(1) Removed reference to pictorial standards available from FSCT.(2) Added referenc

35、e to ISO 4628 Part 5.(3) Expanded photographic reference to four full-size photographs.(4) Removed reference to standard D1150, since it has been withdrawn.(5) Added sections for Test Specimens, Procedure, and Report.(6) Included a Precision and Bias Statement.ASTM International takes no position re

36、specting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This

37、 standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Intern

38、ational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown be

39、low.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 188