Designation:D3456−86(Reapproved2012)StandardPracticeforDeterminingbyExteriorExposureTeststheSusceptibilityofPaintFilmstoMicrobiologicalAttack1ThisstandardisissuedunderthefixeddesignationD3456;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticeprovidesguidelinesfordeterminingthesusceptibilityofpaintfilmstomicrobiologicalattackonexteriorexposure.Whileitisrecognizedthatvariousorgan-ismsmayoccuronanexposedcoating,thespecifictypesoforganismsaremainlyofacademicinterest.Thedegreetowhichmicrobiologicaldiscolorationoccursistheprimaryconcern.1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D1006PracticeforConductingExteriorExposureTestsofPaintsonWoodD1849TestMethodforPackageStabilityofPaintD3274TestMethodforEvaluatingDegreeofSurfaceDis-figurementofPaintFilmsbyFungalorAlgalGrowth,orSoilandDirtAccumulation3.SummaryofPractice3.1Simpleobservationofacoatedobjectsubjectedtoexteriorexposureisconsideredapracticalandreliablemethodfordeterminingthedegreethatmicroorganismsdiscolorthecoating.However,thisappliestoaspecificcoatedobjectexposedunderagivensetofconditions.Itshouldberecog-nizedthattherearecriticalfactorsthatinfluencetheamountoffungalgrowththatmayoccuronthesamecoatedobjectwhenexposedtootherconditions.Thesefactorsincludethegeo-graphiclocation,localatmosphericconditionssuchasthedustandpollencontentoftheair,angleofexposure,degreetowhichthecoatingissubjectedtoweathering,effectsofmoistureandsunlight,thesubstratesonwhichthecoa...
