ASTM_D_7539_-_10_2015.pdf

Designation:D753910(Reapproved 2015)Standard Practice forUsing a Test Chamber for Humidity Conditioning of TestPanels of Pavement Marking Paints1This standard is issued under the fixed designation D7539;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.1.Scope1.1 Specification D3924 defines a standard environment of23 6 2C and 50 6 5%relative humidity and free from draftsfor normal conditioning and testing of paint,varnish,lacquer,and related materials.This practice describes a test chamberthat allows for control of relative humidity above the ambientrelative humidity and minimization of air flow for conditioningof test panels at elevated relative humidity and room tempera-tures.1.2 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.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D711 Test Method for No-Pick-Up Time of Traffic PaintD1640 Test Methods for Drying,Curing,or Film Formationof Organic CoatingsD3924 Specification for Environment for Conditioning andTesting Paint,Varnish,Lacquer,and Related MaterialsD7377 Practice for Evaluating the Water Wash-Off Resis-tance of Traffic Paints using a Water FaucetD7538 Practice for Evaluating the Water Wash-Off Resis-tance of Traffic Paints Using an Atomizing Spray Device2.2 Other Standard:3TT-P-1952E Federal Specification for Paint,Traffic andAirfield Marking,Waterborne(10 July 2007)3.Terminology3.1 Definitions:3.1.1 test chamber,na cabinet or box,preferably made oftransparent,waterproof material,such as clear acrylic plastic,with panel supports and holes(ports)that can be partially tofully opened to mix outside ambient air with humidified air inthe chamber or some other means to provide humidified airwith minimal air flow.3.1.1.1 DiscussionAlso commonly referred to as a humid-ity box or humidity chamber,as in Federal SpecificationTT-P-1952E.3.1.2 waterborne pavement marking(traffc)paint,nanaqueous paint used for marking pavements.4.Summary of Practice4.1 Atest chamber is described that allows for the control ofrelative humidity above ambient relative humidity and theminimization of air flow variability at ambient room tempera-tures.5.Significance and Use5.1 The drying rate of organic coatings varies with changesin temperature,air flow,and relative humidity.In particular,thedrying rate of waterborne paints depends on the evaporation ofwater and thus is much more dependent on relative humiditythan are solvent based paints or paints that are 100%solids.Measurement of the rate of drying of waterborne paints underambient conditions in laboratories cannot be adequately repli-cated without some control of the drying conditions.A testchamber will be described that provides a means of controllingrelative humidity above ambient humidity and minimizing theeffects of air flow variability at ambient room temperatures.Ifdesired,the test chamber without water in it and with ventswide open can be placed in a temperature and humidity1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved June 1,2015.Published June 2015.Originallyapproved in 2010.Last previous edition approved in 2010 as D7539 10.DOI:10.1520/D753910R15.2For 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.3Available from General Services Administration,Federal Supply Service,Specification Section,Suite 8100,470 LEnfant Plaza,SW,Washington DC 20407,http:/www.gsa.gov.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 controlled room to test dry speed at various temperatures aswell as humidity while using the chamber to minimize theeffect of air flow.5.2 This practice is particularly useful for testing the dryingrate of waterborne pavement marking(traffic)paints where fastdry at elevated ambient humidity is an important feature.Forwaterborne traffic paints,the test chamber can be used toevaluate dry to no-pick-up(Test Method D711)and waterwash-off resistance(Practices D7377 and D7538)at elevatedambient humidity.6.Apparatus and Equipment6.1 Test ChamberThe re