ASTM_D_1653_-_13.pdf

Designation:D165313Standard Test Methods forWater Vapor Transmission of Organic Coating Films1This standard is issued under the fixed designation D1653;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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 Department of Defense.1.Scope*1.1 These test methods cover the determination of the rate atwhich water vapor passes through films of paint,varnish,lacquer,and other organic coatings.The films may be free filmsor they may be applied to porous substrates.1.2 A similar,but more generally applicable test method isTest Methods E96 which should be considered when othermaterials are involved.1.3 Two test methods are covered in Test Methods D1653 asfollows:1.3.1 Test Method ADry Cup Method,and1.3.2 Test Method BWet(Payne)Cup Method.1.3.3 Agreement should not be expected between resultsobtained by different methods or test conditions.The methodthat most closely approaches the conditions of use should beselected.1.4 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.Factors for conversion arestated in 13.2.1.2 and 13.2.2.2.1.5 There are instruments on the market that purport tomeasure water vapor transmission of films more easily andrapidly than the methods described in Test Methods D1653 andE96.They run essentially the same kinds of tests as in theASTM methods,but do so instrumentally.However,it appearsthat no side-by-side tests have been run comparing results frommeasurements with such instruments to these ASTM methodsfor precision and accuracy.1.6 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thicknessof Paint,Varnish,and Related Products on Test PanelsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1193 Specification for Reagent WaterD4708 Practice for Preparation of Uniform Free Films ofOrganic CoatingsE96 Test Methods for Water Vapor Transmission of Materi-alsE104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 water vapor transmission rate,WVT,nthe steadywater vapor flow in unit time through unit area of a body,between two specific parallel surfaces,under specific condi-tions of temperature and humidity at each surface.Acceptedinch-pound unit is grains per square foot per hour.Accepted SIunit is grams per square metre per 24 h.3.1.2 water vapor permeance,WVP,nthe steady watervapor flow in unit time through unit area of a body(WVT)induced by unit vapor pressure difference(p)between the twosurfaces of a coating.Therefore,WVP=WVT/p.Acceptedinch-pound unit is grains per square foot per hour per inch ofmercury(called a perm).Accepted SI unit is grams per squaremetre per 24 h per millimetre of mercury(called a metricperm).3.1.3 vapor source,nhumidity in the dry cup method andwater in the wet cup method.3.1.4 vapor sink,ndesiccant used in the dry cup methodand 50%or near 0%relative humidity in the wet cup method.4.Summary of Test Methods4.1 In Test Method A(Dry Cup Method),the test specimenis sealed to the open mouth of a cup or dish containing1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.23 on Physical Properties of Applied PaintFilms.Current edition approved June 1,2013.Published July 2013.Originally approvedin 1959.Last previous edition approved in 2008 as D1653 03(2008).DOI:10.1520/D1653-13.2For 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 standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 desiccant,and the assembly placed in a test chamber with acontrolled atmosphere.Two sets of exposure conditions areacceptable for this test method.4.1.1 Condition A,consisting of 50%relative humidity at73F(23C),and4.1.2 Condition B,consisting of 90%relative humidity at100F(38C).4.2 In Test Method B(Wet Cup Method),the test specimenis sealed to the open mouth of a cup or dish containing water,and t