1、Designation: D5064 16Standard Practice forConducting a Patch Test to Assess Coating Compatibility1This standard is issued under the fixed designation D5064; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the procedures for assessing coat-ing compatibility when maintenance of an in-place coatingsystem is being cont
3、emplated. It does not address proceduresfor assessing the integrity of the existing coating to determineif it can be repainted, nor does it establish the compatibility ofthe maintenance coating system with the substrate or corrosionproducts. The practice is intended for use in the field.SSPC-TU 3 di
4、scusses the risks associated with the mainte-nance painting practice known as overcoating.NOTE 1Pass-Fail Criteria (for example, adhesion requirements) arenot established by this practice. These should be established by the user orspecifier with input from the coating manufacturer.1.2 The values sta
5、ted in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety a
6、nd health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, andApplicationsD3359 Test Methods for Measuring Adhesion by Tape TestD4138 Practices for Measurement of Dry F
7、ilm Thickness ofProtective Coating Systems by Destructive, Cross-Sectioning MeansD4414 Practice for Measurement of Wet Film Thickness byNotch GagesD4541 Test Method for Pull-Off Strength of Coatings UsingPortable Adhesion TestersD6132 Test Method for Nondestructive Measurement of DryFilm Thickness o
8、f Applied Organic Coatings Using anUltrasonic Coating Thickness GageD6677 Test Method for Evaluating Adhesion by KnifeD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic, Nonconductive Coat-ings Applied to Non-Ferrous Me
9、talsD7234 Test Method for Pull-Off Adhesion Strength of Coat-ings on Concrete Using Portable Pull-Off Adhesion Tes-ters2.2 SSPC Standards:3TU 3 Technology Update 3 Overcoating3. Terminology3.1 DefinitionsFor definitions of terms used in thispractice, refer to Terminology D16.4. Summary of Test Metho
10、d4.1 The materials under test are applied to the previouslypainted surface after surface preparation. After the appropriatetime has elapsed, the test patch is examined for visual defectsand adhesion is assessed.5. Significance and Use5.1 In performing maintenance of a coating system, the newcoating
11、being applied must be compatible with the existingcoating. While general guides exist which indicate compatibil-ity of different generic types of coatings, differences inmanufacturers formulation and the condition of the in-placecoating system may affect compatibility.6. Procedure6.1 Select test loc
12、ations for evaluation that adequatelycharacterize differences in configuration of the structure andthe exposure environment; that is, vertical versus horizontalsurfaces; sheltered versus unsheltered exposure; atmosphericverses splash zone or immersion. A minimum of three testlocations with one test
13、patch in each is recommended.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved July 1, 2016. Published August 2016.
14、 Originallyapproved in 1990. Last previous edition approved in 2012 as D5064 07 (2012).DOI: 10.1520/D5064-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the sta
15、ndards Document Summary page onthe ASTM website.3Available from Society for Protective Coatings (SSPC), 800 Trumbull Drive,Pittsburgh, PA 15205, http:/www.sspc.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 The size of each t
16、est patch is limited by the size andconfiguration of the test locations. Each test patch shall be aslarge as possible, with a minimum size of 1.0 m2(10.8 ft2)recommended.6.3 Prepare the surface of the test areas using the methodsspecified for the maintenance painting procedure (Note 2).Alternative m
17、ethods of preparation may also be evaluated inseparate, adjacent tests.NOTE 2This practice is intended to assess compatibility with theexisting coating only and does not apply to areas where the substrate isexposed by the methods of preparation.6.4 Measure the existing coating thickness in accordanc
18、ewith Test Methods D6132, D4138, or Practice D7091,asappropriate for the type of substrate.6.5 Measure the air and surface temperatures, the relativehumidity and the dew point temperatures and verify that theconditions are within the limits recommended by the coatingsmanufacturer for the product(s)
19、being tested.6.6 Apply the test coating to the thickness recommended bythe coating manufacturer. Use the application technique asintended for use during production operations. If agreed uponbetween the purchaser and the seller, the method of coatingapplication may be different from that proposed for
20、 use on thejob, that is, brush application of the test patch even thoughspray application is intended to be used on the job. However,this can cause anomalies in the data and is not generallyrecommended.6.7 Immediately after application, measure the wet-filmthickness in accordance with Practice D4414
21、. Inspect eachpatch for application defects such as runs, sags, and pinholes.If such defects cannot be corrected as a part of the initialapplication process, prepare a new test patch.6.8 After the coating has dried, measure the dry-film thick-ness in accordance with Test Methods D6132, D4138,orD7091
22、. Make corrections to the application, if necessary, byeither applying more material if the dry film thickness is low(build-up coat) or applying another test patch if the dry filmthickness is above the recommended maximum.NOTE 3When using Test Method D6132 or Practice D7091, the dryfilm thickness is
23、 the difference in average thickness of the coating systemless the average thickness of the in-place coating.6.9 Allow the coating to cure and weather prior to evalua-tion. Cure durations are defined as long term and short term.Long-term curing provides the most reliable assessment ofcompatibility.
24、Short-term curing provides for more rapid evalu-ation of results, but may not reveal all potential compatibilityproblems.6.9.1 Long-Term CuringCuring for as long a time aspossible, with a minimum of six months preferred. Curingshould span seasonal weather changes.6.9.2 Short-Term CuringCuring at the
25、 following mini-mum times based on average daily (24 h) temperatures:10C (50F) 21C (70F) 32C (90F)14 days 10 days 7 daysLonger minimum cure times are acceptable if manufacturerrequires longer minimum cure times.6.10 After curing, examine the total surface of each testpatch for wrinkling, blistering,
26、 mudcracking, checking,cracking, peeling, lifting, and disbonding. Measure or rate theadhesion in a minimum of five locations per test patch inaccordance with Test Methods D3359 or D6677. If agreedupon between the purchaser and the seller, adhesion testing inaccordance with Test Methods D4541 or D72
27、34 may be used.6.11 Examine the test patches for the defects noted in 6.10on a regular schedule, discounting rust caused by previous testssuch as adhesion measurements and destructive film thicknessmeasurements.7. Report7.1 Report the following information:7.1.1 The identity of the structure tested,
28、 the location andsize of the test patches, the identity of the test coating, themethod and grade of surface preparation, and the method ofcoating application.7.1.2 For each test patch, the dry film thickness measure-ments and average of the in-place coating, the dry filmthickness measurements and av
29、erage of the test coating, theelapsed time for each evaluation, the visual defects noticed,and the results of adhesion tests.8. Keywords8.1 coating; coating compatibility; coating test patch; paint;paint compatibility; test patchASTM International takes no position respecting the validity of any pat
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