C1193

C1472GuideforCalculatingMovementandOtherEffectsWhenEstablishingSealantJointWidth

D2203TestMethodforStainingfromSealants

3.Terminology

3.1Definitions—RefertoTerminologyC717fordefinitionsofthefollowingtermsusedinthisguide:adhesivefailure,bicellularsealantbacking,blooming,bond-breaker,bridgesealantjoint,buttsealantjoint,cell,cellularmaterial,chalk,chalking,chemicallycuringsealant,closedcell,closedcellmaterial,closedcellsealantbacking,cohesivefailure,compat-ibility,compatiblematerials,compound,controljoint,creep,cure,cured,dirtpick-up,elastomeric,elongation,expansionjoint,filletsealantjoint,gasket,hydrostaticpressure,isolationjoint,fluidmigration,jointfiller,laitance,latexsealant,modu-lus,non-sagsealant,opencell,opencellmaterial,opencelloutgassing,sealantbacking,primer,reversion,rundown,seal,sealant,sealantbacking,self-levelingsealant,shelf-life,sol-ventreleasesealant,shrinkage,siliconesealant,skin,structuralsealant,substrate,tooling,toolingtime,weathertight,workinglife(potlife).

3.2DefinitionsofTermsSpecifictoThisStandard:

3.2.1durability,n—abilityofasealantjointanditspartstoperformitsrequiredfunctionoveraperiodoftimeundertheinfluenceoftheenvironment.

3.2.2durabilitylimit,n—pointatwhichlossofperformanceleadstotheendofservicelife.

3.2.3precuredsealant,n—apreformed,factorycured,elas-tomericmaterial.

3.2.4prematuredeterioration,n—failuretoachievepre-dictedservicelife.

3.2.5servicelife,n—actualperiodoftimeduringwhichnoexcessiveexpenditureisrequiredformaintenanceorrepairofasealantjoint.

4.SignificanceandUse

4.1Thisguideprovidesinformationandguidelinesforconsiderationbythedesignerorapplicatorofajointseal.Itexplainsthepropertiesandfunctionsofvariousmaterials,suchassealant,sealantbacking,andprimer,amongothers;and,proceduressuchas,substratecleaningandpriming,andinstallationofthecomponentsofasealedjoint.Itpresentsguidelinesfortheuseandapplicationofthevariousmaterials,designofasealantjointforaspecificapplication,andenvironmentalconditionsandeffectsthatareknowntodetri-mentallyaffectasealantjoint.Theinformationandguidelinesarealsousefulforthosethatsupplyaccessoriestothesealantindustryandforthosethatinstallsealantsandaccessorymaterialsassociatedwithsealantuse.

4.2Inadditiontothedesignandinstallationdatainthisguide,consultthesealantmanufactureraboutapplicationsforitsproductsandtheirproperuseandinstallation.Consideringtherangeofpropertiesofcommerciallyavailablesealants,thevarietyofjointdesignspossible,andthemanyconditionsofuse,theinformationcontainedhereinisgeneralinnature.4.3Toassisttheuseroftheguideinlocatingspecificinformation,adetailedlistingofguidenumberedsectionsand

theirdescriptorsareincludedinAppendixX2.5.GeneralConsiderations

5.1General—Properselectionanduseofasealantisfundamentaltoitsultimateperformance,servicelife,anddurability.Asealantjointsubjectedtomovementandothersimilarperformancefactorsshouldbedesignedfortheparticu-larapplicationtoavoidcompromisingitsperformancecapa-bilityandcausingfailure(See15).Ifnotdesignedfortheparticularapplication,failureisadistinctprobability.Equallyimportantistheproperselectionanduseofothermaterialsandproductsassociatedwithsealantuse.Theseincludesubstratecleaner,surfaceconditionerorprimer,typeofsealantbackingmaterial,bond-breaker,andjointfiller,amongothers.Theabilityofasealantinstallationtoremainweathertightiscriticallydependentonproperpreparation,continuity,anddurabilityofthesubstratestowhichthesealantwilladhere,andcompatibilityofthesealantwiththematerialsitwillcontact,includingthesubstrates.Theproperapplicationandinstallationofthevariousmaterialsandproducts,followingtheestablishedjointdesigncriteria,avoidsprematuredeteriorationofthesealantjoint.Forasealantjointthatisdifficultorexpensivetoaccess(forexample,tallbuildingsandcertainroofs)asealantshouldbeselectedthatwillhaveexcellentenvironmentalweatheringcharacteristicstominimizemainte-nance.Thefollowingsectionsdescribejointdesignguidelinesandthepropertiesanduseofasealantanditsassociatedmaterials.

5.2Durability—Thedurabilityofasealantandasealantjointisrelatedtomanyfactors.Forexample,environmentalexposuretosolarradiation,ozone,heat-aging,andatmosphericcontaminantscanlessensealantdurability.Inadequatecon-structiontolerancesandimpropersealantjointdesignformovementandothereffectscancontributetosealantjointfailure,whichisusuallyexpressedasadhesiveorcohesivefailureofthesealant.Inadequateinstallation(forexample,wherethesealantprofileisinappropriateformovement,wheresubstrateshavenotbeenproperlycleanedand,ifrequired,primed,andthesealantinadequatelytooled,amongothers)arecommoncausesoffailure.Conditionsofexposureanddesign(where,forexample,asealantjointisexposedtoconstantwettingortopedestrianorothertraffic)canlessensealantandsealantjointdurability.Thetypeofsealant,itsprimarypolymerbackbone,andtheparticularsealantformulationcanalsocontributetolesseneddurability,especiallyifasealantismisusedforanapplicationorforconditionsofusenotappropriateforit.Frequently,variouscombinationsofenvi-ronmentalexposureandconditionsofuseoccurwhichcanresultinlesseneddurability.Forexample,dependingonsealanttype,jointmovementcombinedwithheatagingandcoldweatherexposureorjointmovementcombinedwithheatagingandmoisturecanresultinfailure.Toenhancedurability,itisimportantthatthesealanttypeismatchedtotheconditionsofuseandexposureandthatthesealantjointisofproperdesignforthoseconditionsofuseandexposure.Inanyevent,eventualreplacementofasealantthathasreacheditsdurabilitylimitmustbeplannedforintheinitialdesignandinstallationtofacilitatefutureremedialwork.

5.2.1DurabilityTesting—Presently,testingforsealantdu-rabilityconsistsofexposingsmall-scalesealantsamplestoartificialweathering,withoutcyclingmovement,inalabora-toryacceleratedweatheringdevicetoactinicradiation,mois-ture,andheataccordingtoPracticeC1442.Additionally,environmentalexposureatvariouslocations(forexampleFlorida,Arizona,Texas,andcertainnorthernlatitudes)isalsoconducted.Correlationofartificialweatheringtoenvironmen-talexposureisimportanttoassesstherelevanceoflaboratorytestresultstopredictingsealantperformanceduringenviron-mentaluse(1,2).Laboratoryteststodateindicatethatatleastseveralthousandhoursofartificialweatheringexposureisnecessarytoadequatelypredictaminimumlevelofenviron-mentalperformance.Forexample,ifchangesoccurfivetimesfasterinalaboratorydevicethanunderenvironmentalcondi-tions(atypicalaverageaccelerationfactorforanumberofmaterials),andthedesiredlifetimeofamaterialisaboutfiveyears,asmuchasoneyearofartificialweatheringmaybenecessarytoqualifyamaterialfortheapplication.ThelatestASTMweatheringstandardsrecommendasaminimumexpo-suretimethatnecessarytoproduceasubstantialchangeinthepropertyofinterestfortheleaststablematerialbeingevalu-ated.However,thismaynotbelongenoughtoqualifyamaterialforthedesiredapplication.Environmentalperfor-mancewillvarywithlatitude.Forexample,asealantusedinChicagowillperformdifferentlythanthesamesealantusedinFloridaforasimilarapplication.Compassorientationalsohasaneffect,withanortherlyexposuresealanttendingtolastlongerthanasoutherly.Theincidentsolarradiationisaprimarycontributingfactor,amongothers,tolesseneddurabil-ity.Otherconditionsbeingequal,thesealantinChicagowillingeneralperformforalongertimeperiodthanthesamesealantusedinFlorida.

5.2.1.1Thelatestdurabilitytestingprogramsindicatethatartificialweatheringperformedconcurrentlywithmovementofasealantjointsampleseemstomorerealisticallypredictsealantandsealantjointenvironmentalperformance(3,4,5,6).CurrentASTMlaboratorytestmethods,thatincludeadurabilitycomponent,suchasC719,donotprovideanadequatepredictionofsealantlong-termenvironmentalperfor-manceandthereforepotentialsealantandjointdurability.5.2.1.2TestmethodC719evaluatesthemovementofanewsealantwithoutthebenefitofanyagingorweatheringandtherebyprovidesdataonlyforanunagedsealant.

5.2.1.3Theuserofasealantshouldrealizethatmostmanufacturer’sdatasheetsreportlaboratorytestingdatacon-ductedinanidealized,as-curedstateandnotasaweatheredconditionthatrepresentshowthesealantwillactuallyappearandperformonabuilding.Additionally,theperformanceandotherpropertiesreportedonmanydatasheetsdoesnotincludemovementduringthecuringprocess.

5.2.1.4Almostallbuildingsealantapplicationshavemovement-during-cure.Thesenaturalmovementsduringcurealmostalwaysdecreasetheperformancecapabilityofasealant.Therefore,datasheetperformanceproperties,ifcorrect,gen-erallyoverstatetheexpectedenvironmentalandcyclicmove-mentperformanceofasealant.Withthisinmind,asealantjointdesignshouldalwaysbeperformedwithmitigatingdesignfactorsincludedinthedesigntoaccountformovement-during-cure(See12.5).

5.3Adhesion—Obtainingandthenmaintaininglong-termadhesionofasealantistheprimaryvariableinasuccessfulinstallation.Asealantmanufacturerwilldeterminewhatisnecessarytoachieveadequateadhesiontoaparticularsub-strate,andifaprimerorsurfaceconditionerisnecessary,byusinglaboratorytestmethods.Insomeapplications,glass,metalorothersubstratesmayhavecoatings,surfacetreatmentsordifficult-to-removecontaminantsrequiringspecialcleaningtechniquesorprimers.Duetothissurfacevariability,thesubstratesshouldbesampledandtestedbythesealantmanu-facturerfromactualproductionrunsofthematerials.Specifi-cationC920requiresasealanttoberatedasUseM,A,G,orO.Whenlistedbyasealantmanufactureritindicatesthat,ingeneral,thesealanthasbeenfoundtoadheretoandissuitableforusewiththatsubstratetype.Thisisnotnecessarilyaguaranteeofadhesion.Samplesoftheactualsubstrateshouldalwaysbetestedforadhesionbeforeuse,sincematerialsandfinishescanbevariableorproductscanchangewithtimeandformulationfromthataspreviouslytested.Considerationshouldalsobegiventoidentifyingasealantwhich,withouttheuseofprimersifpossible,willprovideadequateadhesion.5.3.1AdhesionTesting—Adhesionofasealanttoasub-stratesurfaceoranothermaterialorcomponentisdeterminedusinglaboratoryTestMethodsC794andC719.Adhesiontestingbyasealantmanufacturertypicallywillbeperformedafteronedayor7daysofwaterimmersion.Formanyapplicationsthisisnotanadequatetestexposuretopredictlongtermsealantjointperformance.Itistheuser’sresponsi-bilitytoevaluatethewaterimmersionconditionofanadhesiontestconductedbythesealantmanufactureranddetermineifitisapplicabletoaparticularuse.Ifnot,theusershouldobtainappropriatedataconsistentwiththeintendedapplication.Ingeneral,formostmaterials,sealantmanufacturershaveexten-sivepreviousadhesiontestingexperienceandcanusuallyindicateiftheirsealantwillorwillnotadheretoagenericmaterial’ssurface.Therefore,pre-qualificationtesting,priortospecifying,isusuallynotnecessaryunlessthemanufacturerdoesnothaverelevantdataforaparticularmaterialoriftheadhesiontoagenericsubstratevariessignificantly.Carefulreviewofasealantmanufacturer’sdatasheetisimportant,sincesomeonlyreportextensionorsimplecyclicmovementperformancenotincludingalltheTestMethodC719param-etersandconditions.Tomonitorforanysubsequentsurfacechanges,considerationshouldbegiventoevaluatingsubstrateadhesionontheinstalledsubstratesattheprojectsitepriortobeginningtheinstallationofthesealantandperiodicallyduringtheinstallation.AppendixX1describesprojectsiteadhesiontestingmethods.

5.4Compatibility—Asealantmustbecompatiblewiththematerialsandsurfaceswithwhichitwillbeincontact.Occasionally,materialsthatareincloseproximity,butnotincontactwiththesealant,canhaveaneffectontheinstalledsealant.Incompatibilitycancause,asaminimum,adiscolora-tionofthesealantor,atitsextreme,sealantdeteriorationoradhesionloss.Compatibilitymustneverbeassumedbutalwaysestablishedbyaformalprogramoftestingbythe

sealantmanufacturer,sincethereareno“alwayscompatible”combinationsofasealantwithothermaterials.Asealantshouldbetestedforcompatibilitywithothersealantswhichitmaycontactandwithmaterialsandfinishesitcontactsorisincloseproximity.Materialsandfinishes,withtimeandexposuretotheultravioletcomponentofsunlight,canexudeorreleaseplasticizersorothermaterialsintoasealant,whichcancauseasealanttochangecolororloseadhesion.Also,theseaccesso-riescanhavesurfaceresiduesorcontaminantsfrommanufac-turingthatcanmigrateintothesealant.Achangeofsealantcolorisevidenceofapotentiallydetrimentalchemicalreac-tion,andalthoughadhesionmaynotbeinitiallylost,thecolorchangecouldbepredictiveofafuturelossofadhesion.Othersealantcharacteristicsthatcouldalsobeaffectedbyincompat-ibilityincludetheabilityofasealanttocurefully,itsultimatestrengthdevelopment,anditsaestheticqualities.

5.4.1CompatibilityTesting—Materialsorcomponentsthatarenearbyortouchthesealantshouldbetestedforcompat-ibilityusingTestMethodC1087.Thistestisperformedinthelaboratorywithpreparedsamplesofsubstratefinishes,gaskets,andvariousaccessorymaterials,amongothers.Anycolorchangeofthesealantaftertesting,issufficientevidencetocauseadditionalevaluationforuseofthecandidatematerialorfinish.Thistestisusuallyperformedtoprequalifyamaterialorcomponentforuse.Ingeneral,formostmaterials,sealantmanufacturershaveextensivepreviouscompatibilitytestingexperienceandcanusuallyindicateiftheirsealantiscompat-iblewithaparticularmaterial.Therefore,pre-qualificationtesting,priortospecifying,isusuallynotnecessaryunlessthemanufacturerdoesnothaverelevantdataforaparticularmaterial.Animportantaspectconcerningcompatibilityisthatoftenasealantorjointaccessoryissubstitutedatthelastminuteasan“orequal”product.Productsarenotequalincompatibilityunlesstheyareequallytestedforcompatibility.Therefore,ifasealantoranaccessorymaterialissubstituted,thenewcombinationshouldalsobetestedforcompatibility.5.5SubstrateStaining—Asealant,dependingonformula-tionandthequalityofitscomponents,cancausestainingofadjacentsubstratesurfaces.Stainingbyasealantisusuallyduetofluidmigrationorrundown(7-11).Bothporousandnon-poroussubstratesaresusceptibletothisstainingmechanism.Fluidfromasealantcanmigrateintotheporesofaporoussubstrateandthenmigratetoitsexposedsurfaceadjacenttothesealant.Thefluidcanthendiscolorthesubstratesurfaceorbecomeanattractantforenvironmentalpollutionordirtpick-up.Thisstaininghasbeencolloquiallyreferredtoas“clouding”duetoitsvisualappearance.Fluidcanalsomigratethroughtheexposedsurfaceofthesealantandthenrundownontoadjacentporousornon-poroussurfacesandbecomeanattractantforenvironmentalpollutionordirtpick-up.Stainingofporoussubstrateshasproventobedifficultifnotimpossibletocompletelyremove.Removalhasusuallybeenmostsuc-cessfullyachievedusinganappropriatepoultice;however,completeandlastingremovalofthestainisrarelyachieved.Stainingofnon-poroussurfacescanalsobedifficulttoremove.Dependingonthematerial,thetypeoffluid,andthetypeofenvironmentalpollutionordirtpick-up,thestainingmaybeeasilyremovedorcannotberemovedresultinginapermanentstaintothesurface.Developmentofcleaningmaterialsandmethodsmustbeacollaborativeeffortofthesealantmanufac-turerandthestainedmaterialmanufacturer.

5.5.1StainTesting—Laboratorytestingforpotentialstain-ingofaporoussubstratebyasealantcanbeperformedusingeitherTestMethodD2203,C510,orC1248.Thesetestmethodsaretypicallyusedpriortosealantinstallationtotestaspecificsubstratematerialwithaparticularsealant.Itshouldberealizedthatthetestsaremeanttobepredictivebasedonacceleratedlaboratoryproceduresthatattempttoduplicatethenaturalenvironment.Theyarenotalwayssuccessfulindupli-catingthenaturalenvironmentandinidentifyingapotentialstainingcombinationofsealantandsubstrate.Environmentaltestingforstainingcanalsobeperformedusingamock-upoftheparticularsealantandsubstrateexposedtothesameconditionsastheenduse.Thisprocedureisusuallylengthy,sometimestakingyearsbeforeajudgementcanbemadeastostainingpotential.Thesealantmanufacturershouldbecon-sultedforadvicesincetheyhaveahistoryoftheirproductsandstainingpotentialwithparticularsubstratematerials.TestdatafromamethodsuchasC1248shouldbeevaluatedalongwiththesealantmanufacturer’srecommendationandexposuredatafromolderinstallations.

5.6SealantColorChange—Asealant,inuse,canchangecolor.Ajointdesignershouldbeawarethatdevelopingaspecialcolorforaparticularapplicationmightbeinappropriateandadditionallybecomea“throwaway”cost.Thesurfacecolorofsomesealantscanchangeinaslittleasafewyearsdependingonlocalenvironmentalconditions.Colorchangecanbecausedbyblooming,ultravioletandvisibleradiationabsorption,chalking,pollutantsintheatmosphere,dirtpick-up,cleaningsolutions,andadjacentmaterials,amongothers(7-9).Bloomingisthemovementofcomponentsinasealanttoitssurfacewheretheyattractdirtandatmosphericcontaminantstothesurfaceofthesealant,changingitsapparentcolor.Ultra-violetandvisibleradiationabsorptionfromthesuncanpermanentlyalterasealant,dependingonthetypeandqualityofpigmentandstabilizeringredients.Colorsthatseemtobemostaffectedbyultravioletandvisibleradiationabsorptionaregenerallythosecreatedusingorganiccoloringagents.Bettercolorstabilityisachievedusinginorganiccolorants.Thedegreeofcolorchangeduetothiseffectisvariabledependingontheexposureofthesealant(e.g.northerlyversussoutherlyfacing)andtheenvironment(southernversusnorthernlatitudesinthesamehemisphere).Theformationofchalk(apowder)onasealantsurfaceduetochalkingcanimpartanapparentcolorchangetothesealant’ssurfacebyhidingthecolorofthesealant.Mostpowderstendtobewhitishincolor,althoughacolorotherthanwhitecandevelop.Organicpolymerbasedsealants,astheyweather,canbeself-cleaningasrain-watercanwashawaythesurfacechalk.Asealantcandiscolorduetotheaccumulationofatmosphericcontaminantsordirtpick-upastheperiodofenvironmentalexposureincreases.Colorchangecausedbyblooming,chalking,andtheaccumulationofatmo-sphericcontaminantsordirtpick-up,canusuallybecleanedfromthesurfaceofthesealantusingcleaningsolutionsandproceduresrecommendedbythesealantmanufacturer.Build-ingfacadesarenormallycleanedonaperiodicbasis.Cleaning

solutionsusedforotherfacadematerialsmayhaveadeleteri-ousaffectonthecolorandotherpropertiesofasealantandshouldbeverifiedashavingnoaffectbyamock-uptestprogrampriortoapplication.Occasionally,asubstratematerialthatasealantisadheredto,oranothermaterialthatitisinincidentalcontactwith,cancauseacolorchangeinthesealantthroughmigrationofsubstrateormaterialcomponentsintothebodyofthesealant.

5.6.1ColorChangeTesting—TestMethodC1087canbeusedtodetermineifsealantcontactwithamaterialwillcausethesealanttodiscolororloseadhesion.TestMethodC510canalsobeused;however,itsvalueislimitedduetotherelativelyshorttimeperiodforthetest.Further,itwouldprimarilybeusefulforporoussubstratesthatmaybediscoloredbycompo-nentsofthesealantthatmigrateintoit.TestMethodC792canbeusedtoassessthechalkingpotentialofasealant;however,thistestalsohasarelativelyshorttimeperiodforthetest.Itshouldberealizedthatthetestsaremeanttobepredictivebasedonacceleratedlaboratoryproceduresthatattempttoduplicatethenaturalenvironment.Theyarenotalwayssuc-cessfulinduplicatingthenaturalenvironmentandinidentify-ingapotentialcolorchangecombinationofsealantandsubstrate.Acceleratedlaboratoryteststhatuseafullspectrumofradiation,suchasaxenonlamp,aremostusefulinpredictingcolorchange.Environmentaltestingforcolorchangecanalsobeperformedusingamock-upoftheparticularsealantandsubstrateexposedtothesameconditionsastheenduse.Thisprocedureisusuallylengthy,sometimestakingyearsbeforeajudgementcanbemadeastoacolorchangepotential.Thesealantmanufacturershouldbeconsultedforadvicesincetheyhaveahistoryoftheirproductsandcolorchangepotentialwithparticularsubstrateandincidentalcontactmaterials.Thespecifierorusercanalsoconfirmperformancebyobservingolderinstallations.

5.7LiquidImmersion—Somesealantapplications,forin-stanceawaterretentionstructureorawastewatertreatmentfacility,requireasealantthatcantolerateextendedperiodsofcontinuousimmersioninwaterorotherliquids(12,13).Also,certainbuildingjointapplications,suchasforplazasandotherhorizontalsurfaces,cansubjectasealanttointermittentshortorlongtermimmersioninrainwaterorsnowmelt.Waterimmersionofasealantisoftenassociatedwithanacceleratinginfluenceonlossofadhesionofthesealanttoasubstrateanddegradationofpropertiesincludingsealantreversion.Forotherthancontinuouswaterimmersionsituations,itisprudenttodesignjointsthatarenotexposedtoprolongedwaterimmer-sion.Thesejointstypicallyareundersomestressfrommove-mentorothereffectsthat,incombinationwithimmersion,canresultinaprematurelossofadhesion.Animportantconsider-ationinimmersionsituationsisthedevelopmentofaconstantdeadloadduetohydrostaticpressureonthesealantanditsadhesiontoasubstrate.Forsuchapplications,anadhesiontestshouldincludetheeffectofhydrostaticpressureonthesealantanditsadhesiontoasubstrate,aswellasprolongedwaterexposuredescribedin5.7.1.Anappropriatepracticeforasealantjointsubjecttoimmersionistodesignthejointprofileasacontinuous“bathtubplug.”Thisisajointwithtaperedsidesorsimilardesigntocausehydrostaticpressuretoassistinformingacompressionseal,bypushingasealantagainstthesubstrate.

5.7.1LiquidImmersionResistanceTesting—TestMethodC1247canbeusedtoassessadhesionofasubmergedsealanttoasubstrate.Waterorotherliquidscanbeusedwiththismethodtodeterminesealantperformance.However,thismethoddoesnottesttheaddedinfluencesofaconstantstressfromhydrostaticpressureoraninducedsealantstressfromjointmovement.Foraparticularapplication,thistestmaynotbeanacceleratedtestdependingonthetemperatureofthetestliquidusedintheapplication.TheC1247testtemperatureis50°C(122°F)andifthatisalsotheapplicationliquidtemperature,thenthemethodmaynotbeanacceleratedtest.Also,mostavailableimmersiontestdataisbasedoncleanwaterastheliquid.Ifaparticularapplicationhasotherthancleanwaterastheliquid,theusershouldhavethetestperformedwiththeliquidinwhichthesealantwillbeimmersed.

5.8EnvironmentalInfluences:

5.8.1LowTemperature—Alowsubstratetemperaturedur-inginstallationgenerallydecreasesadhesionsincethesealantsurfacewettingcharacteristicisreduced.Also,alowambientairtemperature,dependingonthesealantformulationandpolymerbackbone,canreducetheextrudabilityofasealantandrestrictitsabilitytoflowintojointopenings,therebyformingvoidsinthesealant.Frost,bothvisibleandnon-visible,oricemaybepresentonacoldsubstratesurfaceinhibitingadhesion.Forthesereasons,asealantismoreappropriatelyappliedatanambientairtemperatureabove4°C(40°F).Ifapplicationisnecessarywhenthereisvisiblefrostoriceonasubstratesurface,thefrostoricemustberemovedbysolventwiping,evaporationofthesolvent,andfinallyadrywipe.Thereisariskofnon-visiblefrostformingwhenevaporativecoolingofasolvent,usedtoremovevisiblefrost,causesthesubstratetemperaturetofallbelowthedewpoint.Asimpletest,todeterminethepresenceofnon-visiblefrostonametalsurfaceistoplaceahandonthesurface.Heatfromoneshandwillmeltthefrost,ifitexists,andwetthesurface.Also,foradhesion,themanufacturerofthesealantshouldbeconsultedregardingtheextrudabilityandsurface-wettingchar-acteristicsofthesealantasapplicabletoaparticularsubstratematerial.Alowtemperaturecanbequitedetrimentaltoacuredsealant’sperformance.Alowtemperaturecanretardcureofthesealant.Somesealantsbecomestiffatalowtemperature.Ifthereisjointmovementatalowtemperature,afailurecanresultduetothereducedmovementcapabilityofthesealantandtheincreasedstressgeneratedatthesealantadhesionsurface.Ifalowtemperaturewillbeafactor,thenknowledgeofsealantperformanceatlowtemperatureisfundamentalaswellasknowledgeofitsbrittlepoint(glasstransitiontempera-ture).ItshouldberealizedthatthelowtemperatureusedinTestMethodC719is–26°C(–15°F)andmayneedtobelowereddependingontheparticularlowtemperatureapplication.

5.8.2HighTemperature—Thesealantapplicatorshouldbeawarethatasealantthatismarginalwithrespecttohotweathersagresistancemaypresentaproblemwhenworkingonanapplicationthathasasolarexposure.Asubstratesurface,dependingoncolorandthermalmass,candevelopahigh

surfacetemperature,whichcanexceedasealant’shightem-peraturestabilitylevel.Suchhightemperaturescanoccuronsomedarkcoloredsurfacesinthesummer.Knowledgeofasealant’ssustainedhightemperaturestabilityandtheexpectedin-usesubstratesurfacetemperatureisfundamentaltodevel-opingadurablesealantjoint.Manyorganicsealantswillstarttodeteriorateat70to80°C(158to176°F).AsealantthatmeetsSpecificationC920istestedbymethodC639foritsflow(rheologicalorsag)propertiesatatemperatureof5062°C(12263.6°F).Dependingonaparticularsealantandapplicationthismaynotbeadequate.Hotweathermayalsoacceleratesealantcuretime,resultinginashortenedworkinglifeandtoolingtime,whiletack-freetimewillbereducedandrainresistanceaccelerated.Thisisparticularlyhelpfulforawater-basedsealant,whichisusuallymoresusceptibletoraindamagewithinthefirstfewhoursafterapplication.Ahighsubstratetemperaturecanincreasebubbleformationinasealantfromoutgassingofasealantbackingandthusmustbeavoided(See9.3).

5.8.3Moisture—Sealantinstallation,inunprotectedexteriorlocations,cannotbeperformedduringorimmediatelyafterarainandshouldnotbeperformedwhenthereisathreatorknowledgeofimminentrainfall.However,rainfallafterappli-cationusuallyhasnoseriouseffectonmostsealantsifthesealanthasclearlyformedasurfaceskin.Evenasealantwithaskincanbeaffectedifthereisforcefulimpingementofwater,prolongedflowingofwater,orprolongedimmersionofasealantjoint.Thesealantmanufacturershouldbeconsultedforaspecificrecommendationwhenconfrontedwiththeseorsimilarsituations.Themoisturelevelinaporoussubstratecanalsoaffectsealantadhesion,especiallyforjointsthatoccurinhorizontalsurfacessuchasplazas.

6.Substrate

6.1General—Sealantshavebeendevelopedtosealjointsbetweennumeroussubstratematerials,themorecommonofwhicharebrickandconcretemasonry,concrete,variousmetals,stone,andglass.Substratesaregenerallyclassifiedaseitherporousornon-porous.Somesubstratesaregenerallymoredifficulttoadheresealanttothanothers.Surfacecharac-teristicsvaryconsiderably,andsomesubstratesmaynotbesuitableforachievingajointsealunlesstreatedeithermechani-callyorchemically,orboth.Thesubstratemustbeproperlypreparedinallcasesofuse.Thesubstratemustbeclean,dry,sound,andfreeoflooseparticles,contaminants,foreignmatter,water-solublematerialandfrostandice.6.2Types:

6.2.1Porous—Materialsrepresentativeofthistypearebrickandconcretemasonry,concrete,unpaintedwood,somebuildingstones,andmostcement-basedmaterials.Theclassi-ficationofamaterialasporousisgenerallyrelatedtoitshavingaporestructureinthebodyofthematerial.Awater-repellenttreatmentorcoatingonaporoussubstratemayinhibitsealantadhesion.Sincethesecoatingsarenotalwaysvisuallyappar-ent,theirexistenceissometimesunknownuntilanadhesionfailureoccursortestingisperformedbeforeinstallation.Theseconditionsrequirespecialconsiderationandconsultationwithboththesubstrateandsealantmanufacturerstodeterminesuitablesubstratepreparationmethodsandwhichprimer(s),if

required,shouldbeusedbeforeasealantisapplied.Often,reliabilityofaselectedcleaningandprimingmethodcanbepredictedonlybyadhesiontestingofatrialapplicationattheprojectsiteonprojectmaterials.Otherproblematicconditionsaresealantincompatibilitywithotherchemicalproductsonaporousmaterial,suchasconcretesurfacelaitance,whichprovidesaweaksubstrate,andanadhesion-inhibitingform-releaseagentonaconcretesurface.Itisthereforeessentialthatthesematerialsberemovedfromaporoussubstratesurface.Substrateporositycanalsoacceleratesealantadhesionlosswhenthesubstrateiswettedorimmersed.Aprimerorsurfaceconditioner(See8)mayimprovesealantadhesiondurability,evenifnotrequiredforadequateinitialadhesion.

6.2.2Non-Porous—Stainlesssteel,lead-coatedcopper,andanodizedaluminum,factory-appliedorganiccoatings,paints,andglassareexamplesofmaterialsthatareconsiderednon-porous.Thesematerialsarenon-absorptive.Aproprietarytreatmentorprotectivecoatingonametalsurfacemayinhibitsealantadhesionandshouldberemovedcompletely.Whereapaintedorcoatedmetalisthesubstrate,theadhesionofthepaintorcoatingtothesubstrateaswellasthecompatibilityandbondofthesealanttothepaintorcoatingisamatterofconcern.Also,non-porousmaterialsareoftenofthetypethatcan’tbecutandreshapedataprojectsite.Thisbecomesaconcernwhenajointopening,duetoworkmanshiporotherconsiderations,hasbecomesmallerthantheminimumaccept-ablewidthforthejointdesign.Typically,thejointopeningcannotbemodifiedtomakeawiderjointtopermitapplicationoftheplannedsealant.Whenthisoccurs,eitheradifferentsealantwithgreatermovementcapabilityshouldbeinstalledorthejointdesignshouldbechangedtoafilletorbridgetypesealantjointifaestheticallyacceptable(See14.1.4.5and14.2).6.2.3EIFS—AnExteriorInsulationandFinishSystem(EIFS)presentsaporoussubstratethatmaybeacceptableforsealantadhesionprovidedcertainproceduresarefollowed(14-16).Mostmanufacturersrecommendadheringsealantdirectlytothebasecoatandavoidingadhesiontothefinishcoatwhichcansoftenonexposuretomoistureandloseadhesionasthesealantextendsandexertsastressonthefinishcoat.Typically,asealantthathasalowmodulusshouldbeused.Alowmodulussealantwillhavealowerstressatthesealantandsubstrateinterfacewhenthejointisinextension.DuetothedifficultythatcanbeencounteredinperformingremedialworkforanEIFSsealantjoint,theselectedsealantshouldhaveverygoodenvironmentalweatheringcharacteris-ticssothatitwilllastfortheusefullifetimeofanEIFSinstallation.SinceanEIFSsystemiswater-based,ifitbecomessaturatedwithrainwaterorsnowmelt,theadhesionofasealanttoanEIFSbasecoatcanbelessened.InformationonsealanttensileadhesionpropertieswhenusedwithEIFScanbefoundinGuideC1382.EIFScannottolerategrindingorcuttingduringsealantremovalsoitisagoodcandidateforuseofabridgetypesealantjointorprecuredsealant,inaremedialsealantapplication.Thismaybehelpfulsinceitdoesnotrequiretheremovalofalltheoldorfailedsealantbutdoeschangetheappearanceofthejointseal.

7.Cleaner

7.1General—Thequalityofacleaningmethod,cleaning

solution,andcleaningcloths,amongothers,isasimportantasthequalityofasealant.Thesurfacestowhichasealantwillbeappliedmustbeproperlycleaned.Anydeleterioussubstances,suchasoil,grease,orpowderydepositsthatmayinterferewithadhesion,mustberemovedcompletely.7.2Procedure:

7.2.1PorousSubstrate—Grinding,brushing,blowingoffwithoil-freecompressedair,andwipingwithclothsaretypicalproceduresthatareusedtocleanaporoussubstrate.Solventsarenotgenerallyusedsincetheytendtodissolvecontaminantsandthenre-depositthemintheporesofthematerialwheretheybecomeverydifficulttoremove.Aporoussubstrateshouldbefreeofdust,dirtandanyothercontaminantthatwouldinterferewithsealantadhesion.Concrete-basedsub-stratesshouldhaveanylaitanceremoved.Laitanceisanunsoundsurfaceforsealantadhesion.Grindingorbrushingshouldbeperformedwithmaterialsandtoolsthatwillnotleavedeleterioussubstances(e.g.metalorfibrousparticles)detrimentaltosealantadhesion.

7.2.2Non-PorousSubstrate—Degreasingsolvents,suchasmethylethylketone(MEK),toluene,xylene,acetoneandmineralspiritshavebeenusedascleaners.Manyofthesesolventsareregulatedduetotheirpotentiallyhazardousnatureandvolatileorganiccompound(VOC)content.Itisnecessarytoknowtheenvironmentandsafetyprovisionsforaspecificapplicationbeforeaparticularsolventisselectedforevaluationasacleaner.Somesolventsthatmaybeconsideredappropriateareeffectivedegreasersbutcanleavearesiduefilmonthecleanedsurface,whichshouldberemoved.Aresiduefilmcanberemovedusingasolutionoffiftypercentisopropylalcohol(IPA)andfiftypercentwater.However,thissolutionisnotaneffectivedegreaser.Atwostepcleaningmethodcanbeused.Thefirststepisasolvent,whichisadegreaserfollowedbythesecondstep,whichisasolutionofIPAandwatertoremoveanyresiduefilm.Thesealantapplicatorshouldworkcloselywiththesealantmanufacturertodevelopasuitablecleaningprocedureasdeterminedbytesting(See16.4.4).Whenre-ceivedatashoporconstruction-site,andpriortouse,acleaningagentshouldhaveitsqualityverified.Smallquantitiesoforganicandothercontaminants,intheshippedcleaningagent,canadverselyaffectadhesionofthesealanttoacleanedsurface.Additionally,containersforstorageanduseofacleaningagentmustbeclean.Cleaningcloths,rags,orpaperwipesmustalsobefreeofcontaminantsandbelintfree.Somecommerciallyavailabledisposableclothsorwipescontainadditives,suchaslanolintoimprovesoftness.Theseadditiveswillcontaminateasurfaceandaffectsealantadhesion.8.Primer

8.1General—Thepurposeofaprimeristoimprovetheadhesionofasealanttoasubstrate.Aprimerfunctionsinthreeways.First,itchangesthechemicalcharacteristicsofthesubstratesurfacetorenderitmoresuitableforthesealant.Secondly,itstabilizesthesubstratesurfacebyfillingporesandstrengtheningweakareas.Lastly,itreducescapillarypressureofmoisturethroughasubstratesurface.Somesealantsrequiretheuseofaprimeronallsubstrates,whilesomerequirethemononlycertainsubstratesoronnoneatall.Theneedforaprimerandtheadhesionresultsachievedcanvary,notonlywiththesubstratetype,butalsowiththequalityofthesubstrate.Noconsistentrecommendationcanbemaderegard-ingwhichsubstratesurfaceswillrequirepriming.Primingisdependentonthesealantmanufacturer,sealanttypeandformulation,substrate,and,insomeinstances,useandexpo-sure.Withsomesealantsdifferentprimersarerequiredfordifferentsubstrates.Thisposesadifficultapplicationproblemwhentwodifferentsubstratesrequiretwodifferentprimersonoppositesidesofajointopening.Thisshouldbeconsideredwhenselectingasealant.Manysealantsrequireaprimerformaximumadhesiontoconcreteandmasonrysurfaces.Todetermineifaprimerisrequiredforaspecificapplication,performadhesiontestingasdescribedin5.3.1.

8.2Materials—Aprimerorsurfaceconditionerisaspe-ciallyformulatedliquiddevelopedandrecommendedbythemanufacturerofthesealant.Aprimer,ifrequired,isnormallyfurnishedbythesealantmanufacturerandistypicallyformu-latedforuseonlywiththesamemanufacturer’ssealant.Aprimerfromonesealantmanufacturershouldneverbeusedwithasealantfromanothermanufacturerunlessithasbeentestedandapprovedbythemanufacturerofthesealantwithwhichitwillbeused.Somesealantmanufacturershaveseveralprimersthatareusedwiththeirdifferentsealantsandwithdifferentsubstrates.Selectionofaprimerforusewithaparticularsealantandsubstrateorsubstratefinishshouldbetheresponsibilityofthesealantmanufacturerbasedondataobtainedfromtestingperformedonsubmittedsubstratefinishsamples.Asforasealant,aprimermustbestoredandappliedinaccordancewiththemanufacturer’srecommendationsandusedwithinitsstatedshelf-life.

8.2.1Color—Itisnotuncommonforaprimertobeclearaswellasvariousshadesofpink,redoryellow.Thesealantmanufacturershouldestablishanacceptableprimercolor,anditsrange.Aprimerthatdoesnotconformshouldbediscardedandreplaced.Aprimerofquestionablecolororonethatisdifferentfromthemanufacturer’sdescriptionshouldneverbeused.

8.2.2Clarity—Clarityisoftenconfusedwithcolor.Aclearprimerisfreeofparticulatematterorsettlingandisnotcloudy.Aprimermaybewater-whiteorvariouscolors,suchas,pink,red,yelloworsomeothercolor,andalsoclear.Thesealantmanufacturershouldestablishtheneedforanddegreeofclarity,andtheacceptabilityofsolidmaterialinaprimer.Aprimerofquestionableclarityoronethatisdifferentfromthemanufacturer’sdescriptionshouldneverbeused.8.3Application:

8.3.1General—Dippingaclothorbrushinacontainerofprimermayresultininadvertentcontaminationoftheprimer.Frequently,anapplicatorwilluseasqueezebottletopourprimeronaclothorbrush(See16.4.6.1).Thelengthoftimeaprimermustcurebeforethesealantcanbeappliedshouldbeasrecommendedbythesealantmanufacturer.Withsomeprimers,asealantcanbeappliedalmostimmediately,whilewithothersalengthycuretimeisrequired.Thelatter,whencompliedwith,cancauseconstructionschedulingdifficultiesforthesealantinstallerforsomeapplicationsandshouldbetakenintoconsideration.

8.3.2PorousSubstrate—Oftenasealantwillrequirea

primerforadequateadhesiontoporoussubstratesurfaces,especiallyconcreteandmasonry.Aprimerisappliedtoaproperlycleanedandpreparedporoussubstrateusuallyusingabrush.

8.3.3Non-PorousSubstrate—Dependingonthesurface,asealantmayrequireaprimerforadequateadhesiontonon-poroussubstrates,especiallysomemetalsandorganicfactory-appliedcoatingsorpaintfilms.Aprimeronanon-poroussurfacewillgenerallyfunctionbychangingthechemicalcharacteristicsofthesubstratesurfacetorenderitmoresuitableforadhesionofasealant.Aprimeristypicallyappliedtoaproperlycleanedandpreparednon-poroussubstrateusingaclean,lint-free,uncoloredcloth.

9.SealantBacking

9.1General—Aproperjointdesignwillrequiretheselec-tionanduseofsealantbackingtoensureanticipatedperfor-manceandaweathertightjoint.SealantbackingshouldmeettherequirementsofSpecificationC1330.Somenon-absorptivesealantbackingsmayactasasecondarybarrierintheeventofsealantfailure(See9.5.3).Itisnotexpectedthatthesecondarybarriercanaccomplishthisintentcompletely,orthesealantwouldnotberequired.Foranapplicationwherethedegreeofwaterabsorbencyofasealantbackingisaconcern,thebackingcanbeevaluatedusingTestMethodC1083.SealantbackingandsealantcompatibilitycanbeverifiedbyusingTestMethodC1087(See5.4.1).Ifthesealantbackingistobeusedinajointthatwillexperiencemovement,thenthesealantbackingshouldnotcauseorcontributetoathree-sideadhesionconditionthatwouldrestrictmovementofthebackofthesealantjointbetweensubstrates.Materialsthatarecom-monlyusedforsealantbackingincludepolyurethane,polyeth-ylene,andpolyolefinfoams.Thesematerialsarefabricatedorextrudedintosealantbackingthatcanhaveaninternalcellularstructurethatiscomposedofopen-cellmaterial,closed-cellmaterial,oracombinationofboth.Theuseofsealantbackingtowhichthesealantwillnotadhere,orthatissosoftastonotrestrictsealantmovement,mayprecludetheneedforabondbreaker.Somesealantbackingmaybeincompatiblewiththesubstrateandsealantandcausestainsoneitherorboth.Materialsimpregnatedwithoil,bitumen,non-curingpolymers,andsimilarmaterialsshouldnotbeusedassealantbacking.Somesealantbackingmaybefactory-coatedwithasuitablematerialthatwillprovideabarriertostaining.Toconfirmsuitability,thebarriercoatingshouldbeacceptabletoboththesealantandsealantbackingmanufacturers.Whenrequired,abondbreakermayalsobecapableofperformingthefunctionofabarrieragainststainingofthesealant.9.2Function:

9.2.1Normal—Asealantbackingforabuildingjointappli-cationcanhavethreeprimarypurposes.First,itisusedtocontrolthedepthandshapeofthesealantinthejointopening.Secondly,itassistsinattainingfullwettingofthesubstratewhenthesealantistooled.Lastly,dependingontype,itallowsmovementofthebacksideofthesealantbetweensubstrates.Asealantbackingshouldbecapableofresistingpermanentdeformationbeforeandduringsealantapplication.Asealantbackingforthisapplicationisaflexibleclosed-celloropen-cellplasticfoam,closed-cellorspongerubberrodorotherappro-priateshapethatiscompatiblewiththesealant.Thesealantshouldbeappliedimmediatelyaftersealantbackingplacementtopreventwaterabsorptionfromrainorcondensation.Duetotheeaseofcompressibilityofopen-cellfoamsealantbacking,thistypeofsealantbackingcanbeusedinvaryingjointwidthsprovidedthatadequatecompressionofthebackingismain-tained.

9.2.2TemporaryJointSeal—Sealantbackingcanserveasatemporaryjointsealforweatherprotectionorasasecondarybarrierbehindtheprimesealantbarrier,orboth.Asatempo-raryseal,anelastomericgasketwithlowcompressionset,suchasclosed-cellfoamorrubber,shouldbeselectedforbuildingjointapplications(walls).Asealantbackingforthisapplicationmaybecompatibleelastomerictubingorrodofsuchmaterialsasneoprene,butyl,orEPDM.Thesemaybeappliedimmedi-atelyasatemporarysealuntilthesealantisapplied,afterwhichtheyservetoalimiteddegreeasasecondarywaterbarrier.Aswithclosed-cellsealantbacking,thesematerialsshouldbenon-absorbenttowaterandgasandnotbloworemitgasuponmildheatingorrupturing,sincethiscancausebubblingofthesealant.Inaddition,thissealantbackingshouldhavetheabilitytoremainresilientattemperaturesaslowas–26°C(–15°F)andhavelowcompressionset.9.3Material:

9.3.1OpenCellFoam—Anopen-cell,sponge-typematerialsuchasurethanefoamcanbeused.Thismaterialmaybesatisfactoryforanapplication,provideditswaterabsorptioncharacteristicsarerecognized.Itshouldnotbeusedwherewaterabsorptionbythesealantbackingmaybedetrimentaltosealantperformance,suchasforahorizontaljointorwherecondensationorinfiltrationofwatercanoccurbehindthebackinginaverticaljoint.Anopen-cellsealantbackingisnormallymadefromapolyurethanematerial,whichisfabri-catedintovarioussizecylindrical,rectangular,orothershapesthatdonothaveasurfaceskin.Bynothavingasurfaceskintheriskofoutgassingisavoided.Duetoitsopencellstructurethissealantbackinghasalowdensityandiseasilycompressibleintoplace.However,theopencellstructurecanwickandretainwaterthatmayinfiltratebehindthesealantjointorthroughothersystemdeficiencies.Theuseofanopencellsealantbackingshouldbecarefullyevaluatedsothatthepossibilityofawater-saturatedsealantbackingindirectcontactwithasealantisprecluded,orwherecondensationorinfiltrationcanoccurbehindthesealantbackinginaverticaljoint,particularlybeforethesealantcures.Opencellsealantbackingthatisuncompressedshouldhaveawidthapproximately40to50percentgreaterthanthejointwidth.Thiswillensureadequatecompressionwheninplace,sothatitwillnotfalloutofthejointbeforesealantapplicationorbedisplaceddeeperintothejointopeningwhenthesealantistooledagainstit.Anopencellsealantbackingmaterialwillallowasealantthatcuresbyexposuretoatmosphericmoistureorairtocurefromtheinteriororunexposedsealantfaceaswellasitsexposedface,therebyacceleratingsealantcure.Forsomeapplications,wheremovementduringcureisexpected,anopencellsealantbackingmaterialcanbebeneficialtoacceleratingsealantcureandminimizingsealantexposuretomovement-duringcure.

9.3.2ClosedCellFoam—Aclosed-cellfoamsealantback-ingisnon-absorbenttoliquidwaterandgasandshouldnotemitgasuponmildheatingasthiscancausebubblingofthesealant.Generally,thissealantbackingmaterialisusedwherethejointopeningwidthisconstantwithlittlevariation.Aclosedcellsealantbackingisusuallymadefromapolyethylenematerial,butalsofromneoprene,butylorEPDMandcombi-nationsthereof.Itisextrudedusuallyintovarioussizecylin-dricalorsheetshapesthathaveasurfaceskin.Duetoitsclosedcellstructurethissealantbackinghasalowdensityandislesseasilycompressibleintoplacethananopencellsealantbacking.However,theclosedcellstructuretendstonotwickandretainwaterthatmayinfiltratebehindthesealantjointorthroughothersystemdeficiencies.However,ifproperwork-manshipisnotemployedduringinstallation,thesurfaceskinofthebackingcanbepuncturedandthebackingcanout-gasintoanuncuredsealantproducingvoidsandotherdefectsinthecuredsealant.Thisconditioncanresultinwaterinfiltrationandcompromisetheabilityofthesealanttoaccommodatemove-ment.TestMethodC1253cantestsealantbackingforout-gassingpotential;however,itteststheoutgassingpotentialofapurposelypuncturedsealantbacking.Aconditionthatthismethodwillnotidentifyisaclosedcellsealantbackingthathasathinskinthatfollowinginstallationsubsequentlyrupturesduetoenvironmentalconditions.Cautionshouldbeexercisedwheninstallingthissealantbackingtoavoidpuncturingitorcausingexcessivecompression.Closedcellsealantbackingthatisuncompressedshouldhaveawidthapproximately25to33percentgreaterthanthejointwidth.Thiswillensureadequatecompressionwheninplace,sothatitwillnotfalloutofthejointbeforesealantapplicationorbedisplaceddeeperintothejointopeningwhenthesealantistooledagainstit.9.3.3BicellularFoam—Thissealantbackingisnormallymadefromapolyolefinorpolyethylenematerialwhichisextrudedtypicallyintovarioussizecylindricalshapesthathaveasurfaceskin.Ithasanopencellstructurewithasurfaceskin.Duetoitssurfaceskin,ithasthewaterabsorptioncharacter-isticsprimarilyofaclosedcellsealantbacking;however,thecutendscanwickandretainwater.Duetoitscombinationofopenandclosedcellcore,ifthesurfaceskinispuncturedthisbackingwillnotout-gasintoanuncuredsealant.However,theskincanwrinkleorfoldoverwheninstallingthesealantbackingintoajointopeningifitisoversizedfortheopeningorinstalledbypressinginwardononesideofthesealantbacking.Foldingoverofthebicellularsealantbackingwillresultinasealantprofilethatmaynotbeconduciveforoptimummovementperformance.Itisusefulfortexturedorroughsubstratesurfaceslikesomeexposedaggregateprecastconcrete,whereskinpuncturingislikely.

9.3.4Others—Somejointapplicationsmayrequireuseofanelastomericmaterial,suchasbutyl,EPDM,neoprene,orotherpolymersfabricatedintoanappropriateshape.Thesematerialscanbeformulatedasaclosed-cell,spongeordenserubbergasket.Thegasketmaythenfunctionassealantbacking.Theperformancepropertiesoftheseothermaterialsareusuallymatchedtoaspecificapplication.Forexample,inpedestrianwalkways,thesealantbackingmayhavetobeahigh-densitymaterialtoassistinresistingtheimpactofahighheelshoeonthesealantsurface.Useofthesematerialsisdependentuponappropriatecompatibilitytestingofaparticu-largasketwiththeproposedsealant(See5.4.1).Additionally,abondbreakertapemayberequiredtoseparatethegasketfromthesealantandpreventthree-sideadhesionfromdevel-oping.

9.4ShapeandForm:

9.4.1Round—Thisshapeisthemostcommonlyusedforbutttypesealantjoints.Itcreatesaconcaveinboardfaceonthesealant.Thevarioustypesofsealantbackingmaterialsareproducedinseveraldiametersforapplicationinavarietyofjointopeningwidths.

9.4.2Rectilinear—Somesealantapplicationsmayrequireasquareorrectangularshapesealantbacking.Asanexample,ahorizontalexpansionjointinamasonrywallmayrequirethisshapetoappropriatelyaccommodatewallflashingandsealant(17).Asealantjointthatiswideandshallowwilloftenusethisshape.Toaccommodateinstallation,apressuresensitiveadhe-siveandreleasepapercanbeappliedtooneface.

9.4.3Triangular—Afillettypesealantjointismosteffectiveifatriangularshapedsealantbackingisusedattherootofthejoint(18).Toaccommodateinstallation,apressuresensitiveadhesiveandreleasepapercanbeappliedtooneface.Triangularsealantbackingcanbefabricatedfromopencellpolyurethaneorclosedcellpolyethylenefoam.Somemanu-facturersprovidequarter-roundsealantbackinginlieuoftriangular.

9.5Application:

9.5.1VerticallyOrientedSurface—Asurfacethatisslopedfromverticalnomorethan15degreesisgenerallyconsideredasvertical.Onethatisslopedmorethan15degreesshouldbeconsideredasahorizontalsurfacerelativetochoiceanduseofsealantbacking(See9.5.2).Opencell,closedcell,andbicel-lularsealantbackingcanbeusedforajointinaverticalsurface.Choiceofmaterial,anditscellularstructure,isdependentonaparticularapplication.Waterabsorptionchar-acteristicsofasealantbackingmaybeadecidingfactor.Watersaturatedsealantbackinghasbeenidentifiedasacauseofsealantadhesionlossand,insomecasesdeteriorationofasealant,wheninprolongedcontactwithit.

9.5.2HorizontalSurface—Sealantbackingforjointsinfloors,pavements,sidewalks,plazas,patios,andotherlighttrafficareasisgenerallymadefromextrudedclosedcell,highdensityfoam,resinimpregnatedfiberboard,orelastomerictubingorrods.Thesealantbackingmaterialshouldhaveatleastthefollowingproperties.Itshouldremainresilienttotemperaturesaslowas–26°C(–15°F);shouldexhibitgoodcompressionrecovery;shouldnotout-gas,causedbyheatingorrupturing,resultingintheformationofvoidsinthesealant;andshouldnotabsorbwater.Inaddition,itshouldbecapableofprovidingsupportforthesealantintrafficareas.Asealantbackingcansupportthesealantinanarrowhorizontaljointsealsubjecttopedestrianorvehiculartraffic.Forajointmorethan50mm(2in)wide,ametalplatewithabondbreakerisnormallyusedunderthesealanttosupportit,especiallywhenthesealantisusedforvehiculartraffic(SeeFig.1).Sealantbackingandjointfillershouldnotexudeliquidsundercom-pression,asthiscouldexertsufficienthydraulicpressureto

ABCDEFGsealant

removablejointfiller

premoldedjointfillercastinconcrete

sealantbackinginstalledundercompressioninaccordancewithmanufacturer’sinstructionsbondbreaker(useoverslidingmetalsupport)shoulderprovidesverticalsupportsubstrate

FIG.1UseofSealantBackingandJoint-FillersinHorizontalApplications

causesealantfailurebyforcingthesealantfromthejointopening.Variouscombinationsofsealantbackingandjointfillerareoftenusedtosatisfytheseveralrequirementsofahorizontaljointseal.Forexample,premoldedjointfillermaybeusedtoformajointopeninginconcrete.Atsealantinstallationtime,therecessabovethejointfillermaybewetandcontaminatedorthejointfillermaynotbecompressedagainstthesubstrates,duetoshrinkageofconcreteorthermalmovementofthejointopening,permittinglossofsealantifaself-levelingtypeisused.Theproblemmayberesolvedbyallowingagreaterrecessabovethepremoldedjointfiller,orbyusingajointfillerwitharemovablestrip.Thestripisremoved,replacingitwithanadditionalsealantbackingundercompres-sion,acrossthejointopeningwidth,andtotheproperdepth,justpriortoapplicationofthesealant(See14.1.5.3andFig.1).9.5.3TemporaryJointSeal—Sealantbackingcanfunctionasatemporaryjointsealforweatherprotectionwhencondi-tionsareunsuitableforimmediatesealantapplication.Asatemporaryjointseal,itissubjecttoweathering,andnormallyshouldbereplacedpriortosealantapplicationwithanewpermanentsealantbacking.Insomecases,thetemporarysealantbackingmaybesuitableforuseasapermanentsealantbacking.Thefollowingconditions,however,wouldrenderitunsuitableandnecessitatereplacementwithnewmaterial;ifitbecomeswet;ifitbecomesdirtyorotherwisecontaminated;ifittakesacompressionsetandwillnotremaininplaceundertoolingpressure;ifitssurfacehasbeendamagedorrupturedorpuncturedduringthecleaningoperationpriortosealantappli-cation.Iftheintentistousethetemporarysealantbackingasapermanentsealantbacking,andthereisaquestionastoitssuitability,thesealantmanufacturershouldbeconsultedforarecommendation.

10.JointFiller

10.1General—Useofajointfillerisfrequentlyencoun-teredinconcreteandmasonryconstructiontoform,forexample,anexpansion,control,orisolationjoint.Frequently,thejointisdeeperthanthethicknessthatresultsfromthesumofthesealantdepthandits(usuallyround)sealantbacking.

Theremainingjointdepthisoccupiedwithapermanentjointfiller.Materialstypicallyusedforthejointfillerincludeclosed-cellpolyethyleneformasonryjointsandcompressibleasphaltimpregnatedcanefiberforconcretejointssubjecttotraffic.Thesematerialsarefabricatedintothedesiredshape,usuallyrectilinear.

10.2Function—Thejointfillercanprovideadditionalsup-portforthesealantanditssealantbackingwhenajointoccursinahorizontalsurfacesubjecttotraffic.Additionally,inmasonrywallconstruction,itcanbeinstalledasthemasonryisconstructedtoprecludemortardroppingsfromoccupyingthejointopening.Mortardroppingsinajointopeningareincom-pressibleandwillpreventamovingjointfromproperlyclosingduetothermalorothermovements.Thejointfilleralsoneedstobecompressibleenoughtoavoidrestrictingjointmovement.11.BondBreaker

11.1General—Abondbreakershouldbeusedtopreventadhesionofasealanttoanysurfaceormaterialonwhichadhesionwouldbedetrimentaltotheperformanceofthesealant(SeeFig.2).Abondbreakerisnormallyaself-adhesive,pressuresensitivetape,usuallymadefromaTFE-fluorocarbonorpolyethylenematerial,towhichasealantwillgenerallynotadhere.Theuseofducttapeasabondbreakermaterialisunacceptable.Amaterialimpregnatedwithoil,bitumen,anon-curingpolymer,orsimilardeleteriousmaterialshouldalsonotbeusedasabondbreaker.Abondbreakerhasverylowornoadhesiontoasealanttherebyavoidingathree-sideadhesioncondition.Liquid-appliedbondbreakerisnotrecommendedduetothedifficultyofinstallingitontheintendedsurfacewithoutcontaminatingthesealantadhesionsurface.Abondbreakershouldbeappliedtothebottomofajointcontainingarigid,non-flexiblesealantbackingmaterialortoarakedmortarjointtoprecludethepossibilityofthesealantadheringtothesematerialsandformingdetrimentalthree-sideadhesionwheremovementwilloccur.Abondbreakerisnotrequiredtopreventasealantfromadheringtoasoft,flexible,opencellsealantbackingmaterialthatwouldnotsignificantlyrestrictthefreedomofmovementofasealant.

ABCDEsealant

sealantbackingsubstratebondbreakerjointfiller

FGHInoadhesionadhesion

failureatstressconcentrationnobondbreaker

FIG.2SealantJointConfigurationsExperiencingMovementandIllustratingEffectofThree-SideAdhesion

Typically,theyarealsousedwheredimensionalconstraintsprecludetheuseofaconventionalsealantbacking.Frequently,inremedialsealantworkabridgetypesealantjointisrequired,whereinabondbreakertapeisusedtoseparateanoldsealantfromthenewandtopermitthedesignedmovementcapabilityofthenewsealant(19).

11.2CompatibilityandAdhesionTesting—Whenbondbreakertapeisrequiredforanapplication,itscompatibility(See5.4.1)andlackofadhesionwithasealantshouldbeconfirmedbytesting.Instanceshaveoccurred,whereinanewlydevelopedsealantformulationhashaddetrimentaladhesiontoapreviouslyacceptablebondbreakermaterial.Sealantmanu-facturersarecontinuallyimprovingtheadhesioncharacteristicsoftheirproductswhich,insomecases,mayresultinasealantadheringtoabondbreakertapeofaparticularmaterialorformulation.Bondbreakertapeandsealantmanufacturerscanprovideinformationontheuseofparticularproductsfromeachmanufacturerandcompatibilityandlackofadhesioncharac-teristicswhenusedincombination.Ifreliableandcurrentinformationisunavailable,asimpleadhesiontestcanbeperformedeitherinalaboratoryorataprojectsite.

11.2.1AdhesionTestMethod—Asampleofthesubstratefortheprojectoranysuitablesizesubstratethatthesealantwilladheretoisacceptable.A100mm(4in)lengthofbondbreakertapeisappliedtoaproperlypreparedandcleanedsubstratesurface.Onthebondbreakertapeandsubstrate,athinrectangularlayerofsealantabout3mm(1⁄8in)thick,aminimumof50mm(2in)long,andwiderthanthetapebyatleast25mm(1in)oneachsideofthetape,isappliedand

tooledcrosswisetothetape.Thesealantisallowedtocureasrecommendedbythesealantmanufacturer.Usingafinger,thesealantisliftedfromthesurfaceofthetape.Ifthereisnoadhesionofthesealanttothebondbreaker,thesealantwillreadilyliftfromthetapesurfacewhileremainingadheredtothesubstratesurface.Ifthereisresistancetoseparationofthesealantfromthetapesurfaceitmaynotbeappropriateforaparticularapplication.Ifthesealantadherestothetapeitisunacceptableforuseasabondbreakermaterial.

12.Liquid-AppliedSealant

12.1General—Aliquid-appliedsealantisclassifiedasasingle-componentormulti-componentmaterialandofanon-sagoraself-levelingformulation.Thetack-freetimeandcuretimeofasealantmaybeimportantsealantselectioncriteria.Itmaybenecessary,dependingontheapplication,touseasealantwitharelativelyquicktack-freetimetoprecludesurfacedamagetothesealantortolimitdirtpick-upataconstructionsite.

12.2CureTime—Thecuretimeofasealantshouldalwaysbeconsidered.Dependingontheapplication,afastcuresingle-component,amulti-component,oraprecuredsealantcanberecommendeddependingonthecuringcircumstancesrequired.Asealantwitharelativelyslowcuretimewhenplacedinajointthatisaffectedbyrelativelyrapiddimensionalchange,thatisusuallythermallyinduced,maybeexposedtomovement-during-cure(See12.5).Typically,rapiddimen-sionalchangeoccurswithamaterialthathaslowthermalmassanddarkcolorationsuchasadarkanodizedaluminumcurtain

wall.Asealantjointinamaterialthathashighthermalmass,suchasaconcreteormasonrywall,willhaveadimensionalchangethatisslowerandcuretimecanbelesscritical.Somesealantsareespeciallysensitivetothelevelofambienthumidity.Inclimateswithalowrelativehumidity,theselec-tionofasealantrequiringatmosphericmoistureforcuringmayresultinanextendedcuretimewhichisaknowncauseforearlyfailureduetosealantmovement-during-cure.Ifcuretimeisanimportantconsideration,aparticularsealantandjointdesignshouldbeevaluatedforsuitabilitytotheapplication.12.3Type:

12.3.1Single-Component—Asingle-componentsealantre-quiresnomixingandisfurnishedtypicallyreadyforapplica-tioninatubeorsausage-shapedpackageandoccasionallyinabulkcontainer.Typically,thecuretimeofasingle-componentsealantislongerthanthatofamulti-componentsealant,sinceatmosphericmoistureisusuallyrequiredforcuringofthesealant.Thequantityofavailableatmosphericmoistureishighlyvariabledependingonthetimeofyearandgeographiclocationofanapplication.Asingle-componentsealantispurposelyformulatedforaslowercuretimeforpackagingreasons(toincreaseshelflife).Generally,useofasingle-componentsealant,inanaridordesertregion,isdiscouragedbysealantmanufacturers,sincecompletecuremaynotbeattainedinareasonableperiodoftime.

12.3.2Multi-Component—Amulti-componentsealantismixedattheprojectsitejustpriortoapplication.Typically,thecomponentsintwo,orinsomecasesthree,containersarecombined.Aprincipaladvantageofamulti-componentsealantisarelativelyrapidcuretimeaftermixing,sincealltheingredientsforcuringofthesealantarecontainedwithinthecombinedcomponents.Disadvantagesincludetheinconve-nienceofmixingbyanapplicatorandaconcernthatthecomponentswillnotbethoroughlyandproperlymixed.Afrequentlyencounteredmixingproblemistheintroductionofairintothemixturebyimproperuseofthemixingequipment.Failuretomixthecomponentsinaccordancewiththemanu-facturer’sinstructionswillresultinthesealantnotattainingitsintendedperformanceproperties.Impropermixingcanalsotrapairbubblesinthesealant.Propermixingusuallyrequiresaslow-speedmixingdevice,mixingforadesignatedperiodoftime,andperiodicscrapingofcomponentsfromthesideandbottomofthecontainer.Toguardagainstinadvertentspillsofsealantcomponents,mixingshouldoccuronadisposablesurfacesuchasatarp.12.4Formulation:

12.4.1Modulus—Thetermmodulus,whenusedforaliquid-appliedsealant,isdefinedasstressatacorrespondingstrain(elongation).Thestrainisexpressedasapercentoftheoriginalat-restdimension.Forexample,asealanthavingastressof689kPa(100psi)at50%strainwouldbecalleda689kPa(100psi)modulussealant.Thisusageisnotinaccordancewithstandardengineeringterminologywheremodulusistheratioofstressdividedbystrain.Forpracticalpurposes,itisaqualitativemeasureoftherelativestiffnessofacuredsealant;andindirectly,thelevelofstresscreatedattheadhesionsurfacewhenthesealantisinextension.Whenasealantisinextensionforanextendedperiodoftime,tensionmodulusbecomesanimportantconsideration.Forexample,whenasealantisadheredtoaconcretesubstrate,andthesealantjointisinextension,thetensilestrengthoftheconcretemustbegreaterthanthetensilestrengthofthesealantotherwisefailureofthesubstrate,bycrackingorspalling,isadistinctpossibility.Themodulusofasealantshouldbematchedtothecharacteristicsofthesubstratetowhichitisadhered.Thesealantindustryhasgenerallycategorizedasealantashavingalow,medium,orhighmodulus.Onemustbecautiouswhenreadingamanufac-turer’sliteraturesincethesedesignationshavenostandardizedmeaning.Whatonemanufacturermaydescribeasalowmodulussealantanothermightdescribeasahighmodulus.Thebestassurancetheuserhasistobeawareofthelevelofstresscreatedattheadhesionsurfacebyjointmovementwhencomparingdifferentsealantproducts.Thereisalsoacompres-sionmodulus,whichisrelatedtotheforcethatisproducedwhenajointisincompression.Asealantthatisveryhardorstiffcanexertanunacceptableforceontheadhesionsurfacewhenajointexperiencescompressionand,insomeinstances,causingfailureofafriablesubstratebyspalling.

12.4.1.1Low—Asealantinthiscategoryusuallyhasarelativelyhighmovementcapability.However,modulusisindependentofmovementcapabilityandalowmodulussealantimpliesthatwhenextendeditcreatesarelativelylowstressatthesealantandsubstrateinterface.Thereareapplica-tionswherethisisdesirable.Forinstance,asubstratethatisrelativelylowintensilestrengthorwithanEIFSsubstrate.12.4.1.2Medium—Asealantinthiscategoryisusedforgeneralpurposejointsealingapplications.Amediummodulussealantrepresentsthemajorityofelastomericproductsthatareusedinthesealantindustry.Theyareusedforjointsthatexperiencemovementandforothergeneralsealingapplica-tions.

12.4.1.3High—Asealantinthiscategoryistypicallynotusedforjointsthatexperiencemovement,since,wheninextension,arelativelyhighlevelofstresscanoccuratthesealantandsubstrateinterface.Itisoftenusedasaglazingsealantwhereinglassorotherpanelsaresealedintoaframingsystemandexpectedmovementislow.Therecanbeahighmodulussealantwithahighelongationcharacteristic;how-ever,inextensionitwillexertaveryhighforceonthesealantadhesionsurface,thusrequiringagoodqualityandstrongsubstrateandverystronganddurablesealantadhesiontothesubstrate.Whenusingahighmodulussealant,careshouldbetakentodevelopanadhesionsurfacedepthsufficienttonotexceedthesealantadhesivestrengthorthestrengthofthesubstratesurfacewhenthesealantisexperiencingjointexten-sion.

12.4.2MovementCapability—Aliquid-appliedsealantmeetingSpecificationC920isratedforcyclicmovementcapabilityusingTestMethodC719.Typicalsealantmovementratings,asdescribedbySpecificationC920,areclass121⁄2and25.Theclassdesignationindicatesthatasealanthasthecapabilityof6121⁄2and625percentmovement(6meansplusandminus).Forexample,usingaclass25sealant,ajointthatis13mm(1⁄2in)widewheninstallediscapableofcompressionto10mm(3⁄8in)andextensionto16mm(5⁄8in)withoutexperiencingadhesiveorcohesivefailure.Thisclass

designationconventiondiffersfromthatusedbymanyothercountries.Aliquid-appliedsealantmeetingSpecificationC1311isratedashavinga671⁄2percentmovementcapabil-ity,andforthosemeetingSpecificationC834nomovementratingisassigned.Theseratingsaredeterminedinacontrolledlaboratoryunderidealcircumstances.Theabilityofasealanttoexhibititsfullmovementcapability,inatypicalapplication,isalsoafunctionofpropersealantjointdesign,appropriatesubstratecleaningand,ifrequired,priming,correctinstallationofthejointcomponents,andsatisfactorysealantinstallationandtooling.Asealantcanrarelydevelopitsfullmovementcapabilityinatypicalapplication.Thenaturalphenomenaofcontinuationofsealantcure,long-termweathering,andmove-mentduringsealantcuringwillresultinlessercapabilitythanitsmanufacturer-documentedmovementcapability.Therefore,theinformedjointdesignerwilluseasealantatlessthanitsratedmovementcapabilityasdeterminedbyC719.

12.4.3Non-Sag—Anon-sagsealantisagunnabletypeforbuildingjointapplicationandisfurnishedaseitherasingle-ormulti-componentcompound.Althoughreferredtoasnon-sag,thesealantmayexhibitsagcharacteristicsundercertainconditionsoftemperatureandjointwidth(See5.8.2).SagorslumplimitationsareestablishedbySpecification:C834,C920,orC1311.Generally,anon-sagsealantisdesignedtonotsaginaverticalapplicationatambienttemperatureupto50°C(122°F).

12.4.4Self-Leveling—Aself-levelingsealantalsomaybeasingle-ormulti-componentcompound.Itisusedforjointsinhorizontalapplicationsandisformulatedtoself-levelatanambienttemperatureof4°C(40°F)orhigher.Althoughanon-sagsealantmaybeusedforhorizontalapplicationssuchasdeckjoints,theself-levelingtypeiseasiertoinstallsinceitispouredintothejointopeningandnormallydoesnotrequiretooling.Iftheslopeofthehorizontalsurfaceistoogreat,anon-sagsealantmayberequiredtoavoidhavingtheself-levelingsealantflowdownhillundertheinfluenceofgravity.Aself-levelingsealantis,bynecessity,heldtoalevelslightlybelowthehorizontalsurfacetoavoidoverflowwhenpouringandtoaccommodateacuredsealantbulgewhenajointisincompression.Thismaybeobjectionableandshouldbeconsid-eredinthedesignofthejoint.Anon-sagsealantthatcanbetooledflush,butconcave,withthehorizontalsurfacemaybepreferableaestheticallyandtohelpavoidsurfaceabrasionwhencompressed(See14.1.8).

12.4.5Extrudability—Asealant,whethersingle-ormulti-component,isformulatedtohavecertainextrusioncharacter-isticsataspecifiedapplicationtemperatureestablishedbySpecification:C834,C920,orC1311.Asealantnotextrudingproperlyshouldnotbeusedsincethismayindicatepoorquality,lackofpackagestability,orinsufficientworkinglife.12.4.6Conditioning—Asealanthasanoptimumtempera-turerangeforhandling,whichcanvaryconsiderablydepend-ingonthetypeofsealant.Thesealantshouldbestoredatatemperaturewithinthisrangeforatleast16hoursbeforeuse.Whentheambienttemperatureatthejointopeningisbelowthesealantstoragetemperature,thesealantshouldbeusedasquicklyaspossiblesincealowsealanttemperaturecanresultinaverylongworkinglifeforamulti-componentsealant.Conversely,whentheambienttemperatureatthejointopeningisabovethesealantstoragetemperature,thesealantshouldbeusedasquicklyaspossiblesinceahighsealanttemperaturecanresultinaveryshortworkinglifeforbothasingle-andmulti-componentsealant.

12.4.7Painting—Mostsealantscanbepaintedwithwateroroil-basedpaintafterthesealanthascured.However,somecannot(SeeC1299).Mostsilicone-basedsealantsarenotpaintable.Consultboththesealantandpaintmanufacturersbeforepainting.Othertypesofsealantsaregenerallypaintable,butthemanufacturer’srecommendationsshouldbefollowed.Thebestpracticeistoallowthesealanttocureseveraldays(thelongerthebetter)beforepainting.Thiswillallowthesealanttoproperlydevelopasurfaceskinandattainaportionofitsperformancepropertiesbeforepaintingandwillreducepaintcracking.Paintingasealantsurfacetoosoonafterapplicationmayretardthesealantrateofcure.However,itshouldberecognizedthatmostpaintswouldnotaccommodateasmuchmovementasasealantcanandthusapaintedsealantsurfacecracksanddistortsandsometimesdelaminatesfromthesurfaceofahighmovementsealant.Forthosesituations,anappropriatesolutionistouseasealantofacolorsuitabletotheapplicationandnotpaintthesealantsurface.Sometimesapaintedsealantsurfacecanbebeneficial.Thepaintcoatingbecomesabarriertoultravioletradiationpreventingitfromreachingasealantsusceptibletoitsdegradingaffectsandlesseningitsdurabilityastimeprogresses.12.5Movement-During-Cure:

12.5.1DamagePotential—Thepotentialfordamageisrealandtheresultantdamagecanbesevere.Movement-during-curecancreatenumerousformsofdamagetoasealantjoint.Dependingonconditions,movement-during-curecancauseadhesiveorcohesivefailureshortlyafterinstallation(cata-strophicdamage);or,withlesssevereconditions,canreducethemovementcapabilityofthecuredsealant,sometimeswithoutobviouschangetoitssurfaceappearance.Researchhasdescribedvarioustypesofdamagethatasealantcanexperi-encewhenthereismovement-during-cure(20-24).Wrinkles,cracks,andbulgescanforminthesealantsurface.Earlyjointextensiontendstocrackthethinfilmofsealant(skin)thatcanformonsomesealantformulations.Jointcompressionandcyclingtendstocreatebulges,wrinklesandpermanentsealantprofiledeformationfromthatintended.Unfortunately,damagecanoccurwithinthesealantthatisnotalwaysvisibleonitssurface.Voidscanbecreatedwithinthesealant.Ontheinteriorfacingsurfaceofthesealant(sealantbackingface),crackscandevelop.Sometimestheyformnearthesealant’sadhesiontothesubstrate,sincetheuncuredsealantmayadhere(albeitatalowlevel)tothesealantbackingorbondbreakertape,concentratingstressandstrainintheuncuredsealantattheedgeofthebacking.

12.5.2PotentialCauses—Damagefrommovement-during-cureisacomplexconditionthatdependsuponalargenumberofpotentialcauses.Theseinclude,amongothers,timeofdayofsealantinstallation,directionofinitialjointmovement(i.e.compressionorextension),magnitudeofthemovement,andnumberofmovementcycles.Additionalpotentialcausesin-cluderateofsealantcure,natureofsealantcure,solar

exposure,climaticconditions,humiditylevel,aninadequatelydesignedorinstalledjoint,andorientationofajoint.Thejointdesignershouldconsidertheseconditions,whendeterminingaparticularjointdesign.Generally,themagnitudeofjointmovementandthesealantcureratearethetwomostimportantfactorstoevaluateforthedevelopmentofamovement-during-curecondition.Asealantjointthatisinadequatelydesignedorinstalledundersizedisespeciallypronetoamovement-during-curecondition.Themovementcapabilityofaninadequatelydesignedorinstalledjointisusuallysmallerthanplanned.Therefore,movement-during-curerepresentsalargerpercent-ageofplannedmovementcapabilityofthecuredsealantjointresultinginanevengreaterriskofdetrimentalmovement-during-cure.

12.5.3TestMethodLimitations—Asealantjointexperi-encesmovementonafacadeduetothermal,moisture,orothereffects(See12.5.2).Thismovementoccurswhensealantisappliedinajoint,whilethesealantiscuringinthejoint,andafterthesealanthascured.Unfortunately,currentASTMtestmethodsusecuredsealanttestspecimensanddonotyetevaluatetheimpactofjointmovementthatmayoccurwhilethesealantiscuring.

12.5.4SealantTypeandCureRate—Asealantthatrequiresarelativelylongtimetocuretoanelastomericrubber,willhaveanincreasedchanceofmoreandlargermovementsduringcure.Alowenvironmentaltemperaturetypicallypro-longssealantcuretime.Alowenvironmentalhumidityalsotendstoprolongthecuretimeofasinglecomponentsealantthatrequiresatmosphericmoistureforthecuringreaction.Also,asealantthatformsaskinduringcureismorepronetosplitting(cohesivefailure)duringjointextension,sincestressandstrainfromthemovementareconcentratedintheskinwhilethesealantiscuring.Thesefactorstypicallyincreasetheriskofencounteringamovement-during-cureconditionduringacoolseasonandinadryclimate.12.5.5DamageAssessment:

12.5.5.1General—Damagefrommovement-during-curecanariseinanewlysealedjointorduringmock-upevaluationofasealantjoint.Itmaybenecessarytoevaluatethelevelofdamagebyphysicalobservationorlaboratorytest.

12.5.5.2PhysicalObservation—Aqualitativeassessmentofsealantdamageandaquantitativeassessmentoftheextentofsuchdamagecanbemadebyevaluatingtheexteriorsurfaceofthesealantfordefects,suchascohesiveoradhesivefailureorbulging.Additionally,samplesofthesealantcanberemovedfromthejointtoevaluateforthepresenceofinternalvoidsorconcealedadhesiveorcohesivefailure.Unfortunately,otherthanbyexperience,therearenoindustryguidelinesforcorrelatingobserveddamagetoapercentagereductionincuredsealantmovementcapabilitywithoutperforminglaboratorytests.

12.5.5.3LaboratoryTests—Thepreferredmethodofassess-ingtheimpactofsealantdamageistoremovesamplesofthesealantandsubstratefromtheconstruction.ThesamplescanthenbetestedusingTestMethodC719.Sealantcyclingbythismethodwillassistindetermininganewjointmovementcapabilityrating.Ifthesubstratecannotberemoved,thenitmaybepossibletocarefullyandneatlycutafullwidthsealantsamplefromthesubstrateandre-adhereittoanothersubstrateinthelaboratory,usingathinlayerofsealant.AC719cyclingtestcanthenbeperformed.Thisapproachwouldnotbeviableifasealantdefect(s)occursnearthesealantadhesionsurface,whichwouldbedisturbedduringthesealantremovalprocess.12.5.6JointMovement:

12.5.6.1General—Animportantvariableistheamountofjointmovementthatislikelytooccurwhilethesealantcures.Asanorder-of-magnitudeguide,thereissignificantriskofcatastrophicfailureifthejointmovement-during-cureis35percentormoreofthecuredsealantmovementcapability.Asanexample,a13mm(1⁄2-in)widejointwithasealantthathasaC719establishedmovementratingof625percenthasacuredmovementcapabilityof63mm(1⁄8in).Ifasealantexperiencesmovement-during-cureof1.5mm(1⁄16in)thiscouldrepresentaseriousrisktothesealantdependingonitsformulationandpolymerbackbone.Laboratorystudieshavefoundthatseveremovement-during-curecanreducethecyclicmovementcapacityofacuredsealantjointbyasmuchas50percent.

12.5.6.2UseofaMock-up—Atalowerlevelofmovement-during-cure,itisprudenttoevaluatetheriskofaproblemusinganinsituorlaboratorymock-up,orboth,toevaluatethesealantbeforeitsinstallationattheprojectsite.Amovementindicator(sometimesreferredtoasascratchplate)canbeinstalledpriortoinstallationtorecordactualjointmovement.Afieldmock-upispreferabletoalaboratorymock-up,sinceitismorelikelytoberepresentativeoftheactualenvironmentalandmovementconditions,unlessinstalledtoofarinadvanceoftheactualinstallationofthesealant.Ifthatoccurs,alaboratorymock-upmaybeabletosimulatetheactualenvi-ronmentalconditions.However,itshouldberealizedthattherearenostandardtestmethodsyetformovementcyclingofasealantjointduringcuretosimulateactualenvironmentalconditions.

12.5.6.3ThermalMovement—Typically,thelargestsourceofmovement-during-cureisduetothermalmovement.Asubstratematerial’ssurfacetemperatureisaresultoftheinteractionoftwogeneralcomponents,ambientairtempera-tureandsolarradiationheatgain.Theannualdifferenceinairtemperature(wintertosummer)inmuchoftheUnitedStatesrangesfromabout90°C(50°F)inwarmerregionsto100°C(180°F)incolderregions.Solarradiationheatgainofasubstratematerialrangesfromabout90°C(50°F)foralight-color,highheatcapacitymaterialtoabout180°C(100°F)foradark-color,lowheatcapacitymaterial.Thus,dependinguponthecharacteristicsofawallorothersysteminwhichthesealantisinstalled,anditsgeographiclocation,thesolarradiationheatgaincomponentcanbegenerally33to66percentofthetotalthermalmovement.Ifallofthemovementatajoint,aftercure,isdueonlytothermalmovement,thenthereisfrequentlyasignificantriskofmajorsealantdamageduetomovement-during-cure.Asanexample,asunnyday,inthesesituations,cancreate35percentormoreofthecuredjointmovementcapabilitybywarmingthesubstratematerial.Themostcommonlyencounteredsevereconditionoccurswithadark-color,lowheatcapacitymaterial,suchasawallsystemofbronzecolor,aluminumwallpanels.

12.5.6.4MovementCombinations—Forasealantjointthatexperiencescombinedmovementfromthermalandmoisturechangeorstructuralmovement,therelativepercentageofcuredjointmovementduetothermalchangeisreduced.Thus,amovement-during-cureconditionislesslikely,sinceitgenerallyiscausedbyonlythermalmovement.12.5.7ReducingMovement-During-Cure:

12.5.7.1General—Whensignificantsubstratemovementisexpectedduringsealantcure,thefollowingapproachescanhelpreducetheriskofamovement-during-cureconditionfromoccurring.Theygenerallyfallintothreecategories:acceleratesealantcurerate,reducejointmovement,oruseaprecuredsealant.

12.5.7.2SealantCure—Useasealantthathasafastrateofcure.Ingeneral,amulti-componentsealanttendstocureatafasterratethanasingle-componentsealant.Verifysealantcurerateswithindividualmanufacturersforspecificproducts.Somemanufacturersallowtheadditionofsmallamountsofwaterwhenmixingamulti-componentsealanttoaccelerateitscurerate.Thisshouldonlybedoneonthewrittenadviceofthesealantmanufacturer.Somesealantmanufacturersproduceafastcuresingle-componentsealantandsomehavetestdataontheeffectsofmovement-during-curefortheirvariousproducts.Thesealantmanufacturercanmakeasealantrecommendation,basedonthetestdata,foraparticularapplicationthatinvolvesmovement-during-cure.

12.5.7.3SealantBacking—Useopen-cellsealantbackingtoallowair(anditswatervapor)toreachbothsurfacesofthejointtopromotecurefrombothsurfaces.Open-cellsealantbackingmaybeinappropriateifthereisariskoffutureliquidwaterretentioninthesealantbacking,resultinginpossibleprematuredeteriorationofthesealant,thejointseal,oradhesionofthesealanttothesubstrate.

12.5.7.4JointMovement—Ifappropriatetothejointdesign,alternatejointopeningscanbeblockedtotemporarilypreventcompressivemovement.Doingsoresultsinthatmovementbeingshiftedtemporarilybetweenalternatejoints.Sealantcanthenbeinstalledintheblockedjoints,andfollowingappropri-atecureofthesealant,removaloftheblocks.Thisprocedureisthanrepeatedforthepreviouslyunblockedjoints.Anotherapproachistodelaysealantapplicationuntilafterthestructureisintheshadeandhascooledorduringcloudyormoretemperatedays.Shadecanbecreatedusingtarpsandothershadingdevices,iffeasible.Lastly,ifconsistentwithaparticu-larbuilding’saestheticintent,ajointdesigncanbemadelargerthanthatdeterminedbycalculationusingGuideC1472ifsignificantmovement-during-cureisexpected.

12.5.7.5PrecuredSealant—Aprecuredsealantgenerallyisavailableasagasketorcompressionseal,rectilinearsheet,andamoldedthree-dimensionalshape.Thereareseveralmanufac-turersthatmakeprecured,preformedgasketandcompressionsealshapesthatcanbeusedinlieuofaliquid-appliedsealant.Ingeneral,theycanbeinstalledinthejointopeningundercompressionorcanbeadheredtothejointsubstrateswithanepoxyadhesive.Liquid-appliedsealantmanufacturershavedevelopedprecured,rubbersheetextrusionsandmoldedformsthatcanbeadheredwithathinlayerofanadhesive-sealanttoasubstratesurface(25-28).Theadhesive-sealantusedfora

precuredsealantwilltypicallycurerapidly.Aprecuredsealanthasbeenusedsuccessfully,whenothertechniquesarenotpossible,tosealjointsthatwouldexperiencedetrimentalmovement-during-cureforaliquid-appliedsealant.

13.PrecuredSealant

13.1General—Presently,thereisnospecificationthatde-scribespreformedsiliconesealantextrusionminimumrequiredperformanceproperties.Theseproductsareincreasinglybeingusedinremedialsealantapplicationsfortherepairorreplace-mentoffailedliquid-appliedsealantjoints(SeeFig.3)(29).Theyareespeciallyusefulwhenrepairorreplacementisnotpossiblewithaliquid-appliedsealantorthejointopeningisdeficientformovementcapacityandcannotbeeconomicallyenlarged.Theyhavealsoprovedverybeneficialinsealingofwindow,curtainwall,andskylightsystemsthathaveexhibitedprematuredeteriorationanddevelopedwaterleakage.Addi-tionally,theyareusefulforjointsthatexperiencelargemove-mentduringcure.Aprecuredsealantisformulatedandextrudedbythemanufacturertoprovideaproductwithalowmodulus.Thelowmodulusoftheprecuredsealant,wheninextension,createsalowstateofstressattheinterfaceoftheprecuredsealantwiththethinlayerofadhesive-sealantadher-ingtheassemblytoasubstrate.ThischaracteristicmakestheseproductsmostappropriateforuseonaweaksubstratesuchasEIFSandsomestonesforexample,sandstone.Useoftheseproductsinsuchsituationsisgenerallyreferredtoas“facesealing.”Aprecuredsealantisgenerallynotrecommendedforuseonahorizontalsurfacesubjecttotraffic(unlessprotected)orforabelowgradeapplication.

13.2Type—Generally,aprecuredsealantisextrudedasarectangularprofileinaribbonlikeshape.Aprecuredextrudedsealantisgenerallyavailableinseveralmanufacturerstockedwidthssuchas,25,38,50,75,and102mm(1,1-1⁄2,2,3,and4inches).Theprecuredsealantisgenerallypackagedasarolltypicallyabout30m(100ft)long.Thicknessisdeterminedbythesealantmanufacturer;however,theyaregenerallyavailableinatleasta2mm(1⁄16in)thickness.Dependingonmanufac-turerandapplicationtheycanbeextrudedwithaseriesofribstoassistinobtainingadhesionoftheadhesive-sealanttothe

AprecuredsealantBsubstrate

Cadhesionsurface

Dliquid-appliedadhesive-sealantEfailedsealant

Fbondbreakertape,ifrequired

Gmaskingtape,removeafterinstallation

FIG.3Cross-SectionofaTypicalPrecuredSealantExtrusion

Application

precuredsealant.Othershapes(e.g.accordion)arealsoavail-ableaswellasmoldedcornersandintersections.Dependingontheapplication,amanufacturerwillextrudeormoldacustomshape,providedthereissufficientquantity.Toobtaincontinuityofseal,amoldedshapeistypicallyadheredtoaribbon-likeshapeusingacompatibleliquid-appliedadhesive-sealant.Apreformedsealantextrusionorshapeisadheredtoasubstratesurfacealsousingacompatibleliquid-appliedadhesive-sealant.Thesameconcernsindicatedin7,relativetosubstratecleaning,and5.3relativetoadhesion,alsoappliestotheseproducts,inparticular,foradhesionoftheliquid-appliedadhesive-sealanttoasubstrate.

13.3MovementCapability—Sealantmanufacturersindicatethatprecuredsealantmovementcapabilityisdeterminedpri-marilybyusingamodifiedTestMethodsuchasC719orC1135.Sealantmanufacturersratethemovementcapabilityofaprecuredsealantextrusion,generally,asaplusandminusvalue.Presently,movementcapabilitiesofupto+200%and–75%arecurrentlyavailable.Forexample,a+200,–50product,forajointapplicationrequiringanunadheredwidthof25mm(1in),couldbeexpectedtoflexto13mm(0.5in)andextendtoadimensionof50mm(2in)withoutexperiencingadhesiveorcohesivefailureoftheadhesive-sealant.Theabilityofaprecuredsealanttoexhibititsfullmovementcapability,inatypicalapplication,isalsoafunctionofproperjointdesign,appropriatesubstratecleaningand,ifrequired,primingfortheadhesive-sealant,andsatisfactoryadhesive-sealantandprecuredsealantinstallationandtooling.

13.4EnvironmentalConditions—Aprecuredsealanthasfewenvironmentalrestrictionsrelativetoitsuse;however,anadhesive-sealantthatadheresaprecuredsealanttoasubstratehasthesameenvironmentalconcernsasaliquid-appliedsealant.Wetordampsubstratesandthepossibilityofrainareconditionsthatmustberecognized(See5.8).

13.5Color—Aprecuredsealant,dependingonmanufac-turer,isavailableinseveralstandardcolors.Customcolorsareusuallyavailable,howeveronlybyaminimumquantityorder.13.6Painting—Ifaprecuredsealantisformulatedwithasiliconepolymer,paintingorcoatingitwithconventionalpaintsorcoatingsisnotrecommended.Doingsogenerallyresultsinpaintorcoatingdelaminationfromtheprecuredsealantsurface.Asaresult,itisnotcapableofbeingreliably

paintedwithanythingbutasilicone-basedpaintorcoating.14.SealantJoints14.1Liquid-Applied:

14.1.1General—Aliquid-appliedsealantisusuallyin-stalledinoneofthreegeneralconfigurations;buttjoint,filletjoint,andbridgejoint.Thedesigngeometryofthesejointsealsisrelatedtonumerousfactors,includingdesiredappearance,spacingofjoints,anticipatedjointmovement,sealantmove-mentcapability,substratelayout,andtoolingmethod,amongothers.Figs.4-6indicatesometypicaljointsealapplicationsandterminology.Thetwo-stagerain-screenjointinFig.7isdesignedtoventtotheexteriorandpressureequalizethechamberbetweentheexteriorrainscreensealandtheinteriorairseal(30).Forabuttsealantjoint,theshapeofthesealant(i.e.hourglass,shallowhourglass,shallowrectangular,deeprectangular,andsquare)canresultindifferingperformanceforthesameconditionsofexposure.AnevaluationofbuttsealantjointshapesisavailableinReference(31)

14.1.2Width—Thereareseveralfactorstobeevaluatedwhenestablishingtherequiredwidthofaliquid-appliedsealantjoint.Paramountamongthemisdesigningthesealantjointfortheanticipatedmovement,constructiontolerances,andothereffectsknowntoinfluencethemovementcapabilityofaparticularapplication(See15).Notdesigningajointforatleastanticipatedmovementandtolerancesoftenresultsinfailureofthejointasaweather-seal.Otherinfluencesaffectingtheestablishmentofjointwidthincludedesiredappearance,spacingofjoints,andtoolingmethod.Undernocircumstancesshouldaliquid-appliedsealantbeappliedinajointopeningthatislessthan6mm(0.25in)wide.Itisverydifficultandimpracticabletoinstallsealanteffectivelyinsuchasmallwidthandisgenerallynotrecommendedbymostsealantmanufac-turers.Generally,forajointwidthover50mm(2in)aliquid-appliedsealantinaverticaljointmaysagbeforecuring.14.1.3Depth—Sealantdepthisdependentonthesealantwidthdeterminedbycalculation,thegenericsealantpolymer,andthegeneralsealantjointshape(i.e.butt,filletorbridgeshape).However,thedepthofthesealantatthesubstrateshouldbenolessthan6mm(0.25in).Adepthlessthanthisdimension,unlessrecommendedbyasealantmanufacturer,isdifficulttocreateconsistentlyandcanresultinlessthan

ABCDEsealant

sealantwidthsealantdepthsealantbackingtoolingdepthFGHIJsealantbackingdepthsealantcontactdepthsealantrecessdepthjointfillersubstrate

FIG.4TypicalButtTypeSealantJointCross-Sections

ABCDsealant

sealantwidthsealantdepthsealantbacking

EsealantcontactdepthFsubstrate

Gbondbreakertape

NOTE1—Thesealantsurfacecanbetooledflatasindicatedorconcaveorconvexdependingonanapplication’srequirements.

FIG.5TypicalFilletSealantJointCross-Sections

ABCDEFGHsealant

sealantwidthsealantdepth

sealantcontactwidthbondbreakertapesubstrate

sealantbacking

removablegaskettosetwidthanddepthandserveastoolingscreed

FIG.6TypicalLiquid-AppliedBridgeSealantJointCross-Sections

A25mm(1in.)minimumforaccesstointeriorairseal

Bsealantandsealantbackingpreferredforrainscreen,preformedcompressionsealalsoused

Cpressureequalizationchamber;venttooutside,withchamberbafflesappropriatelyspacedverticallyandhori-zontally

Dsealantandsealantbackinginstalledfromoutsidetofacilitatecontinuityofairseal;buildingframeworkhin-dersapplicationofcontinuousairsealfrominteriorEshouldersrequiredfortoolingscreed

FIG.7Two-StagePressureEqualizedJointSeal

adequatesealantadhesiontoasubstrate.Substratetype,suchasaroughandvariablefinishonaporoussubstrate,mayrequireasealantdepthgreaterthanthefollowinggeneralguidelinestoresultintheminimumrecommendedsealantdepth.Themanufacturerofthesealant,dependingontherequirementsofaparticularapplication,canprovidearecom-mendedsealantdepth.Sealantmanufacturersdonotagreeontherequiredwidth-to-depthrelationshipforabutttypesealantjoint;however,generallyacceptedguidelinesareasfollows:14.1.3.1PorousSubstrate—Forabuttsealantjointincon-crete,masonry,stoneorsimilarporousmaterials,thedepthofthesealantmaybeequaltothewidthofthejointforawidth

from6to13mm(0.25to0.5in).Forawidthfrom13to25mm(0.5to1in)thesealantdepthshouldbeone-halfthewidthor6to13mm(0.25to0.5in).Foragreaterwidth,from25to50mm(1to2in),thesealantdepthshouldnotbegreaterthan13mm(0.5in).Forajointwidthexceeding50mm(2in),thedepthshouldbedeterminedbyconsultingwiththesealantmanufacturer.

14.1.3.2Non-PorousSubstrate—Forabuttsealantjointinmetal,glass,orothersimilarnon-porousmaterials,thedepthofthesealantshouldbe6mm(0.25in)forajointwidthfrom6to13mm(0.25to0.5in).Forawidthfrom13to25mm(0.5to1in)thesealantdepthshouldbenomorethanone-halfthewidthuptoamaximumof9mm(0.375in).Foragreaterwidth,from25to50mm(1to2in),thesealantdepthshouldnotbegreater9mm(0.375in).Forajointwidthexceeding50mm(2in),thedepthshouldbedeterminedbyconsultingwiththesealantmanufacturer.14.1.4SealantJointType:

14.1.4.1ConcaveButtJoint—Ingeneral,forajointthatwillexperiencemovement,thisisthepreferredsealantprofile(SeeFig.8A).Whensealantistooledoveraconventionalroundsealantbacking,an“hourglass”sealantprofileisestablished,whichduringjointmovement,shiftsthepeakstressesawayfromtheadhesionsurfaceandintothemiddleofthesealantjoint.Thisisthemostcommonlyencounteredliquid-appliedsealantjointprofile.

14.1.4.2FlushButtJoint—Forthisjoint,asealantistooledflatandflushwithasubstratesurface(SeeFig.8B).

14.1.4.3RecessedButtJoint—Thisjointdesignissimilartoaflushjointexceptthattheexposedsealantsurfaceisrecessedfromtheexposedsubstratesurface(SeeFig.8C).Thisprofilecanbedifficulttotoolwithjointopeningsthatvaryinwidth.Thisprofileisoftenusedforajointinahorizontalsurfacethatissubjecttopedestrianorvehiculartraffic.Recessingthesealantallowsthejointopeningtocloseduetomovementandtheinducedbulgeinthesealantremainsbelowthelevelofthesubstratesurface.Whenproperlydesignedthisdoesnotpresentatrippinghazardtopassersby.

14.1.4.4FilletJoint—Afilletsealantjointisoftenencoun-teredinremedialsealingwork(SeeFig.5).Frequentlyitisusedbecauseaconventionalbutttypesealantjointisnotapplicable(32).Thiscanbearesultofimproperinitialjointdesignorconstructionandtheimpracticabilityofenlarginganopeningtoinstallsealantinabutttypejointopening.Addi-tionally,itisalsousedonuncappedendsofhollowextrusionswherethereisinadequatesurfaceareaforaconventionalbuttsealantjoint.

14.1.4.5BridgeJoint—Wheninstalledusingaliquid-appliedsealant,alayerofsealant,dependingongenericpolymerandapplicatorskilllevel,isplacedoverthejointopeningfrom3to6mm(1⁄8to1⁄4in)thick(SeeFig.6).Asforafilletjoint,thisprofileisfrequentlyusedinaremedialsealingapplicationtocorrectafailedjointwhenabutttypesealantjointisimpractical.Theyalsofindfrequentuse,incombinationwithanappropriatelysizedbond-breaker,tocorrectfailedlapjointsinmetalcapflashingandothersimilarapplications.14.1.5SealantJointApplication:

14.1.5.1VerticalSurface—Asealantjointonthefaceofaverticalsurfacecanbeorientedvertically,horizontally,oratanyangleinbetween.Typically,thesealantisnotformulatedforawaterimmersionexposure.Characteristicsofwaterflowonthesurfaceofawallshouldbeevaluated,particularlyforslopingandhorizontaljoints,wherewatercanhaveatendencytopoolonornexttoasealantjoint.Frequentorprolongedwatercontactorimmersioncanresultinfailureofthesealantinadhesionoradegradationofthesealant.

14.1.5.2SlopingSurface—Waterflowcharacteristicsforaslopingsurface,suchasaskylight,shouldbeconsidered.Frequently,sealantjointdesignsareencounteredwherewatercanpoolonorcollectandpoolnexttoasealantjoint.Prolongedexposuretowatercanlessensealantdurability,usuallyresultinginlossofadhesion.Additionally,dependingonaparticulardesign,thesealantcanbecomedirtyduetotheperiodiccollectionandaccumulationofwaterbornedirtand

ABCDsealant

sealantbackingsubstrate

convextoolsurface

Eflattoolsurface

Fshapedtooledgetocontroldepth

Grectangulartoolacceptableifjointwidthcanbecontrolled

FIG.8TooledJointConfigurations

othercontaminants.Anadjacentsurface,suchasglassinaskylight,canbecomepermanentlydisfiguredduetothedirtandothercontaminantsthatcancollectnexttothesealantjoint.Aslopingsurfaceshouldbedesignedtoadequatelydrainwaterfromitssurface,therebyprecludingdetrimentalwateranddirtaccumulation.

14.1.5.3HorizontalSurface—Asealantjointforahorizon-talapplicationwithpedestrianaccessmustbecapableofresistingpuncture(SeeFig.1).Typically,sealantandsealantbackingaredesignedtobeelastomeric,therebyallowingfreedomofmovementofthesubstrates.Arelativelyhardorrigidsealantorsealantbackingwouldcompromisemovement.Asharpobjectsuchasaspikeheel,smallpebble,andenvironmentaldebriscanpunctureasealantwhenbackedbyasoft,easilycompressedmaterial.Thiscancausepermanentdamagetothesealantjointandpossiblypresentatrippinghazardtopassersby.Apedestrianjointdesignthathashadsomesuccessconsistsofsemi-solidjointfiller,suchasfiber-board,withabond-breakerappliedtoitssurfaceincontactwiththesealant.Nouniversaldurablesolutiontothisproblemhasbeendeveloped;consequently,aperiodicconditionevalu-ationwithappropriatemaintenanceofhorizontaljointsisarealisticconsiderationandshouldbeaplannedcomponentofafacilitymaintenanceprogram.Additionally,sealantjointsinhorizontalapplicationsshouldbecapableoffreelydrainingwaterduetorainorsnowmelttopreventitsaccumulationonornearthesealantjoint.Providingadequateslopetoahorizontalsurfacefordrainageisimportant.Ingeneral,aslopeofnolessthan3mm(1⁄8in.)per300mm(12in.)isrequiredtohaveadequatedrainagecharacteristics.Mosthorizontalsealantjointapplicationswithexposuretointermittentwaterwilltypicallyrequiretheuseofasubstrateprimerorsurfaceconditioner,especiallyforaporoussubstrate.

14.1.5.4LiquidImmersion—Asealantthatisusedforaliquidimmersionapplicationtypicallyisamulti-componentchemicallycuringformulation.Asealantshouldbeverified,byTestMethodC1247(See5.7.1),thatitissuitableforusewiththeintendedliquidandfortheanticipatedserviceconditionsandlife.Asealantforaliquidimmersionapplicationmustbeappliedtoanappropriatelycleaned,uncontaminated,anddrysubstratesurface.Anopencellsealantbackingshouldnotbeused,sinceitcanretainliquids,whichcanbedetrimentaltosealantdurability.Asealantforliquidimmersionwilltypicallyrequiredasubstrateprimer.Afterapplication,asealantmustcureforatleast7days,orthesealantmanufacturer’swrittencuringperiodfortheapplication,beforebeingsubmergedinaliquid.Ifthesealantjointwillexperiencehydrostaticpressurethenthesealantandsealantbackingorbondbreakermustbeprovidedadequatesupportbyanappropriatelysizedandinstalledandappropriatelyrigidjointfillerorbyuseofanappropriatejointdesign(See5.7).Thisisespeciallyimportantforasealantjointthatis25mm(1in)ormoreinwidth.Formostapplicationsasealantjointisimmersedinarelativelyconstanttemperatureliquid.Iftheliquidtemperaturewillfluctuatesignificantly,thenthesealantjointshouldbedesignedfortheexpectedmovementandtolerances(See15).Typically,asealantforliquidimmersioncanbeusedinahightempera-tureapplication,providedtheliquidtemperaturedoesnot

exceedanupperlimitofabout50°C(120°F).However,thisismanufacturerandproductdependentandshouldbeverifiedpriortouse.

14.2PrecuredSealant:

14.2.1ExtrudedShape—Anextrudedshapeistypicallyinstalledoverafailedsealantoradeficientjointopeningwidthusingabridgetypesealantjointdesign(SeeFig.3).Anextrudedshapecouldalsobeusedinnewconstructionappli-cationsprovidedthejointisproperlydesigned.Whenusedatanexistingjoint,usuallythefailedliquid-appliedsealantdoesnothavetoberemovedprovideditdoesnotprojectoutoftheopeninganddoesnotrestrictanyrequiredjointmovement.Abondbreakertapeisusuallyinstalledoverthefailedsealanttoseparateitfromtheextrudedshapeifthereisaconcernforcompatibilityandtoprovideanunadheredwidthoftheextrudedshapetoaccommodateanyexpectedmovement.Aliquid-appliedadhesive-sealantadherestheextrudedshapetothesubstratesurface.Typically,thewidthoftheadhesionsurfaceisrecommendedtobefromaminimumof6mm(1⁄4in)to9mm(3⁄8in)dependingonthewidthoftheextrudedshape.Cutandtrimmedendsoftwoextrudedshapesorwhenanextrudedshapemeetsamoldedshapearebuttedtogethertightlyandsealedwithaliquid-appliedadhesive-sealant.14.2.2MoldedShape—Amoldedshapetypicallyisusedtosealfailedmetal-to-metaljointsofwindow,skylight,andcurtainwallsystems.Thesejointscanbesealedwithabridgetypeliquid-appliedsealant;however,theuseofamoldedshapewillusuallyresultinabetterperformingandmoreaestheticallypleasingapplication.Thisapplicationusuallyrequiresathree-dimensionalmoldedshapesincemanyofthesejointswilloccuratcornersandotherframingsystemintersections.Additionally,tocompletethesealingfunction,themoldedshapewillinterfaceusuallywithotherextrudedormoldedshapesandtoaglasssurfacewhenrequired.Aliquid-appliedadhesive-sealantadheresthemoldedshape,usuallyalongitsperimeter,tothesubstrateandtotheotherextrudedormoldedshapeswithwhichitinterfaces.

15.DesigningaSealantJointforMovement

15.1General—Designprofessionals,foraestheticreasons,havedesiredtolimitthespacingandwidthofasealantjointonanexteriorwallandatotherlocationsonanewbuilding.Frequently,anarrowwidthjointsuchasa6mm(1⁄4in)widejointisdesired.Analysisoftheperformancefactorsandtolerancesthataffectasealantjointisnecessarytodetermineifa6mm(1⁄4in)widejointwillhavedurabilityandbeeffectiveinmaintainingasealagainstthepassageofairandwaterandnotexperienceprematuredeterioration.Ifperformancefactorsandtolerancesarenotunderstood,andincludedinthedesignofasealantjoint,thenthesealantmayreachitsdurabilitylimitandfailureisadistinctpossibility(33).Sealantjointfailurecanresultinincreasedbuildingenergyusageduetoairinfiltrationorexfiltration,waterinfiltration,anddeteriorationofbuildingsystemsandmaterials.Infiltratingwatercancausespallingofporousandfriablebuildingmaterialssuchasconcrete,brick,andstone;corrosionofferrousmetals;anddecompositionoforganicmaterials,amongothereffects.Deteriorationisoftendifficultandverycostlytorepairwiththecostofrepairworkusuallygreatlyexceedingtheoriginalcostofthesealantjoint

work.GuideC1472canbeusedtocalculatethewidthanddepthrequiredofasealantjointtoaccommodatetheseaffects.Itisapplicabletoasealantwithanestablishedmovementcapacity,inparticularanelastomericsealantthatmeetsSpeci-ficationC920withaminimummovementcapacityrangeof6121⁄2percent.Itisalsoapplicabletoaprecured,elastomericjointsealwithanestablishedmovementcapacity.AjointfornewconstructioncanbedesignedbytherecommendationsinGuideC1472aswellasajointthathasreachedtheendofitsservicelifeandneedsroutinemaintenanceorajointthatrequiresremedialworkforafailuretoperform.ThefollowingbrieflysummarizestheprimaryissuesdescribedbyGuideC1472.

15.2PerformanceFactors—Propersealantjointdesigncannotbeperformedadequatelywithoutknowledgeandunder-standingoffactorsthatcanaffectsealantperformance.Perfor-mancefactorsincludematerialandsystemanchorage,thermalmovement,moistureinducedmovement,liveloadmovement,deadloadmovement,windloadmovement,movementduringsealantcure,elasticframeshortening,creep,shrinkage,andconstructiontolerances,amongothers.Thefollowingsumma-rizesthemostcommonlyencounteredperformancefactors(thatis,typesofmovement,thermalmovement,andconstruc-tiontolerances)thatareknowntoinfluencesealantjointdesign.Performancefactorscanactindividuallyor,asismostlythecase,invariouscombinationsdependingonthecharacteristicsofaparticularjointdesign.

15.3Movements—Therearefourbasicmovementsthatsealantjointsexperience(SeeFig.9).Thesemovementsarecompression(C),extension(E),longitudinalextension(Etransverseextension(EL),andproduceashearingT).Longitudinalandtransverseextensioneffectonasealantjoint.Fre-quently,sealantjointsmustaccommodatemorethanoneofthedescribedmovementsandoftensomewhatsimultaneously.Examplesincludethepreviouslydescribedextensionandcompression,aswellasextensionand/orcompressioncom-binedwithlongitudinalortransverseextension.Theeffectsofthesemovementscanbecombinedtoestablishthejointwidthrequiredfortheexpectedcombinedmovements.Thedesignprofessionalshouldevaluatethetypesofmovementthejoint

Asealant

BsealantbackingCcompressionDsubstrateEextension

ELlongitudinalextensionETtransverseextension

FIG.9TypicalSealantJointMovement

willexperienceanddesignaccordingly.Thermalmovementisusuallythelargestcontributortothesemovements;however,theotherdescribedperformancefactorscanalsocontributetomovement.GuideC1472providesamethodologytotakeintoaccounttheaccumulatedanticipatedmovementsofthejoint(duetothermalandotherperformancefactors)withthemovementcapabilityofthesealant.

15.3.1ThermalMovement—Wallsandothersurfacesonoraroundbuildingsrespondtoambienttemperaturechange,solarradiation,wettinganddryingeffectsfromprecipitation,andvaryingcloudcoverbyeitherincreasingordecreasinginvolumeandthereforeinlineardimension.Thedimensionalchangeofamaterialcausesachangeinthewidthofasealantjointopening,producingmovementinasealant.Thermalmovementisusuallythepredominateeffectcausingdimen-sionalchange.Thermalmovementmayneedtobeevaluatedatdifferentstagesinabuilding’slife;forexample,expectedtemperaturedifferentialsmayneedtobeconsideredforthebuildingwhenitis:1)underconstruction,2)unoccupiedandunconditioned,and3)occupiedandconditioned.Eachofthesestageswillhavedifferentbuildinginteriorenvironmentalconditions,anddependingonthebuildingenclosurematerialorsystembeinganalyzedformovement,oneofthosestagesmayproducethemaximumexpectedthermalmovement.Therequiredjointopeningwidth,dependingonconstructionpro-ceduresandmaterialorwallsystemtypes,couldbeestablishedduringoneofthosestages.Determiningrealisticmaterialorwallsurfacetemperatures,toestablishtheexpecteddegreeofthermalmovement,canbechallenging.GuideC1472providesprocedurestoassistajointdesignerindeterminingmaterialorsystemminimumwinterandmaximumsummersurfacetem-peraturesaswellasinformationtoassistinestablishingjointopeninginstallationtemperatureeffects.Thisinformationisthenusedtodeterminetheexpecteddegreeofthermalmove-mentofamaterialorsystem.

15.4Tolerances—Atypicalbuildingisacombinationofsite-builtandfactoryfabricatedmaterials,components,andsub-systems.Thesematerialsandsystemscanbecombinedandconstructedincomplexarrangements.ASTMandindustrytradeassociations,amongothers,establishindustryrecognizedstandardsforconstructiontolerances(34).Forsomematerialsorsystemstherearenoindustryrecognizedtolerancesortheavailabletolerancesarenotdirectlyapplicabletosealantjointdesign.Intheseinstances,adesignprofessionalshouldevalu-atetheconditionsandestablishtolerancesforsealantjointwork.Awordofcaution:ignoringtheeffectsofconstructiontoleranceswhendesigningsealantjointswillveryoftenresultinafailureofthejointasaseal,andfrequentlyafailureofadjacentmaterialsorsystems,thatduetojointopeningnarrowing,maycomeintodetrimentalcontactwitheachother.Conversely,changingconstructiontolerances,byexceedingindustryrecommendations,needstobecarefullyconsidered,sinceconditionscanbecreatedthatcannotbeeffectivelyachieved.Constructiontolerancesshouldbeindicatedforasealantjointdesign,sincetheyestablishalevelofqualityandmayaffectthecostandperformanceofthework.GuideC1472

providesinformationandamethodologytoincludeconstruc-tiontolerances(material,fabrication,orerection)inacalcula-tiontodetermineasealantjointwidthanditsdepth.16.SealantInstallation

16.1General—Analysisofmanysealantjointfailuresindi-catesthatthemajorityoffailurescanbeattributedtoimproperjointpreparationanddeficientinstallationofthesealantandvariousjointcomponents.Thefollowingbrieflydescribesseveralaspectsthatmustbeconsideredwhenapplyingaliquid-appliedorprecuredsealantinunprotectedenvironmentstoachieveadurableapplication.Alsodescribedarethevariouscomponentsandproceduresthatarerequiredwheninstallingasealantanditsassociatedaccessories.Asealantmanufacturer’swrittenliteratureshouldalwaysbeconsultedforthemanufac-turerrecommendedproceduresandmaterials.Amanufacturerwilldevelopapplicationspecificrecommendationsifsore-quested.

16.2EnvironmentalConditions—Asealantshouldnotbeinstalledduringrainorwhenthereisthethreatofimminentrainfall.Wetordampsubstratesfrompreviousprecipitationshouldbeallowedtodrybeforeapplicationofprimerorsealant.Ingeneral,sealantinstallationbelow4°C(40°F)isdiscouraged,sinceiceorfrostcanformonasubstratewhichisdetrimentaltosealantadhesion.Frequently,iceorfrostisnotreadilyvisibleonasubstrate(See5.8.1).

16.3RemedialSealantWork—Remedialsealantworkusu-allyrequiresatleastthesamejointpreparationrequirementsasforajointinnewconstruction.Obtainingadhesiontosurfacescontaminatedwithafailedsealantcanbechallenging,oftenrequiringgreaterthannormalevaluation,insitutesting,andsurfacepreparation(35,36).Inaddition,itcanrequireaconsideredandcarefulremovalofanoldsealant,sinceitcancontaintoxicorhazardousmaterials.Priortoremoval,samplesoftheoldsealantshouldberemovedandtestedtodeterminethepresenceofmaterials,suchaspolychlorinatedbiphenols(PCB)orasbestos.Removalanddisposalofsuchasealantmustbeconsistentwithapplicablehazardousmaterialsafetyrequirementsandlocallyapplicablelawsorregulations.Typi-cally,themanufacturerofboththeoldandnewsealantshouldbecontactedforrecommendationsandguidelinesforremovalanddisposaloftheoldsealantandapplicationofthenewsealantandaccessorymaterials.16.4Liquid-AppliedSealant:

16.4.1General—Thefollowingsectionsgenerallydescribethevariousproceduresassociatedwithatypicalliquid-appliedsealantinstallation.Eachinstallationshouldbeevaluatedforanychangesoradditionstotheseproceduresrequiredbythatparticularapplication.16.4.2JointOpening:

16.4.2.1Inspection—Ajoint,priortohavingsealantin-stalled,shouldbeinspectedtodeterminethatitisincompli-ancewiththejointdesign.Forexample,arethewidthanddepthwithinthetolerancesestablishedforthejointdesign?Ifitissmaller,thensealantshouldnotbeinstalleduntilthejointdesignerhasreviewedthedeficientjointwidthordepthanddevelopedanacceptablesolution.Ifthewidthisgreater,thensealantusuallycanbeinstalledprovidedthelargerjointisnotaestheticallyunacceptable.Anyjointthatistoexperiencemovementmusthaveaclearopeningwherethesealantandsealantbackingand,ifrequired,otheraccessoriesareinstalled.Incompressiblematerialsinthejointopening,ifleftin-place,willrestrictjointmovementwhentheopeningcloses.Addi-tionally,withcyclicmovement,theincompressiblematerialscanbedislodged,accumulate,andeventuallycausea“ratch-eting”actionthatwillincreasethejointopeningwidthordetrimentallyharmthesubstratematerial(s)causingcracking,bulging,andothersimilareffects.Thisusuallycausesfailureofthesealantorsubstratematerials.Suchjointsshouldhaveincompressiblematerialsremovedbeforeaccessoriesarein-stalledorsealantapplication.Theresponsiblepartiesshouldresolveanyjointopeningdiscrepanciespriortosealantinstal-lation.

16.4.2.2Substrate—Inspectionofasubstrateisrequiredtodeterminethatitissoundandfirmandacceptableforsealantapplication.Asubstratethatisunsound,cracked,orweakshouldberepairedpriortosealantapplication.

16.4.3SealantAdhesionTests—Itcannotbestatedenoughthatadequatesealantadhesiontoasubstratemustbeverifiedbytestingandthenattained.Thesetestscanbeperformedinthelaboratoryandinsituattheprojectsite.

16.4.3.1LaboratoryTest—Asdescribedin5.3,adhesiontestingofasealantwiththeactualsubstratefortheapplicationisrecommendedwellinadvanceofsealantinstallationattheproject.

16.4.3.2InsituTest—Asubstratesamplesubmittedforpre-installationlaboratoryadhesiontestingcan,dependingonthematerial,experiencesubtlechangesduringproductionmanufacturingofthematerialtocausesealantadhesionprob-lems.Forexample,ananodizedaluminumsurfacecandevelopvariablesealantadhesionduetochangesinorinadequatequalitycontrolofasealingbath,whichcanvaryfrombatchtobatch.Itisagoodpracticetoperformaprojectsiteadhesiontestpriortosealantinstallation,evenwhenunusualconditionsarenotsuspected.Additionally,itisalsoadvisabletoperformperiodicadhesiontestingduringsealantinstallationtoverifythequalityofthework.Thesealantmanufacturerrecom-mendedcleaningand,ifrequired,priminginstructionsfortheapplicationshouldbefollowedforaninsitutest.Typically,thesealantisinstalledinthejointandfollowingtherecommendedcuringperiodisexaminedtodetermineifproperadhesionhasbeenachieved.Determinationofadequateadhesioninajointiscurrentlyamatterofjudgementsincethereisnostandardindustryconsensusforaninsitutestmethod.Insomecasesinwhichanexposedsurfaceofasubstrateisalsothesamecompositionasthejointopeningsubstrate,againstwhichthesealantistobeapplied,itmaybepossibletoprepareanadhesion-in-peelsamplefollowingTestMethodC794.Appen-dixX1includesthreemethodsthatcanbeusedforinsitutests.16.4.4JointPreparation:

16.4.4.1SurfaceCleaning—Jointopeningsubstratesur-facesmustbethoroughlycleanedremovingallforeignmattersuchasdust,paint(unlessapermanentprotectivecoating),oil,grease,waterproofingorwater-repellenttreatments,water,surfacedirt,andfrostorice.Ifremedialsealantworkis

performedtheoldandusuallyfailedsealantmustbesatisfac-torilyremovedtopermitproperadhesionofthenewsealanttothesubstrate.

16.4.4.2PorousMaterial—Cleanporousmaterialssuchasconcrete,masonry,andunglazedsurfacesofceramictilebybrushing,grinding,blastcleaning,mechanicalabrading,acidwashing(ifrecommendedbythesealantmanufacturer),orcombinationsofthesemethodstoprovideaclean,soundsubstrateforoptimumsealantadhesion.Whenacceptableaconcretesubstratemaybecutbacktoremoveacontaminantandexposeacleansurface.Removelaitancefromconcretebyacidwashing,grinding,ormechanicalabrading.Removeformoilfromconcretebyblast-cleaning.Removelooseparticlesthatarepresentorthatresultfromgrinding,abradingorblastcleaning,byblowingoutajointopeningwithoil-freecom-pressedair(orvacuuming)priortoapplicationofaprimer,ifrequired,orasealant.

16.4.4.3Non-PorousMaterial—Chemicallycleannon-poroussubstratesurfaces,suchasmetal,glass,porcelainenamel,andglazedsurfacesofceramictilewithasealantmanufacturerrecommendedsolvent.Othermethodsthatarenotharmfultothesubstrateandacceptabletothesubstrateandsealantmanufacturercanbeused.Removetemporaryprotec-tivecoatingsonmetallicsubstratesusingasolventthatleavesnoresidue(See7).Applythesolventwithcleanoil-free,colorlessclothsorlint-freepapertowelsusingthetwo-clothsystem.Donotdipcleaningclothsintoasolvent,alwayspourthesolventontheclothtoeliminatethepossibilityofcontami-natingthesolvent.Asimpletesttodeterminesolventcleanli-nessistowipesomeontoacleanmirrorandlookforanyresiduefollowingevaporationofthesolvent.Donotallowthesolventappliedwiththefirstclothtoairdryonthesubstratewithoutwipingwithaseconddrycloth.Theintentofthetwo-clothmethodistowetthesubstratewithsolventthatisonthefirstclothbywipingthesubstratetoloosenandcollectsomeofthecontaminant.Thisisthenfollowedimmediatelywiththesecondcloth,beforethesolventcanevaporatefromthesubstrate,topickupanyremainingsolventandloosenedcontaminant.Soiledclothsandwipesshouldbereplacedfrequently.Useofwhitewipesorclothsaidsindeterminingreplacementsinceacolorchangeisreadilyapparent.Aone-clothmethodmerelyredepositssurfacecontaminantsonthesubstrateasthesolventevaporates.Thistechniqueshouldnotbeused.Apermanentsubstratecoatingintendedtoremainmustnotberemovedordamaged.Careshouldbetakeninusingacleaningagenttonotdepositcleaningresidueonotherbuildingsurfaces,whichmaydiscolororbecomepermanentlystained.

16.4.5MaskingTape—Sealantdroppingsandsmearsonanon-poroussubstratesuchasglasscanbeverydifficultandtimeconsumingtocompletelyremove.Onaporoussubstratesuchasconcrete,removalfrequentlyinvolvesmechanicalalterationofthesurfaceofthematerialresultinginobjection-ableaestheticcharacteristics.Tohelpavoidthepossibilityofsealantsmearsandthesubsequentrequirementtocleanvisiblesurfacesadjacenttothesealedjoint,maskingtapecanbeusedcontinuouslyalongthejointedges.Careshouldbetakentoapplythetapeatthejointedgesandnotinthejointopening.Tapeshouldonlybeappliedforthequantityofjointtobesealedthesamedayandshouldnotbeleftin-placeuntilthenextday.Doingsomayresultindamagetothesurfaceandmaymakeremovaldifficult.Whenrequired,itmustbeanon-staining,non-absorbent,compatibletapeandmustbeappliedsoasnottoshiftreadilyduringsealantapplication.Itmustalsobecapableofbeingremovedcarefully,withoutdisturbingthesealant,immediatelyaftertoolingofthesealantsurface.Useofhigh-temperaturemaskingtape,suchasthatusedinanautopaintshop,helpsonhotsubstrates.Itpermitsremovalwithoutleavinganadhesiveresidue.Toolingasealanttotheedgeofthemaskingtape,andpreventingitsaccumula-tionunderthetapewhenusedonirregularsurfaces,isanacquiredskillandtheapplicatorcannotdothisadequatelywithoutpracticepriortotheworkbeingperformed.

16.4.6Primer—Primeasubstratesurfacewhenrecom-mendedbythesealantmanufacturer(See8).Primershouldbeinstalledpriortoinstallationofthesealantbackingtoavoidinadvertentprimerapplicationonthebacking.Primeonlythosesurfacesthatwillbesealedwithsealantthesameday.Ifapreviouslyprimedsurfacethatwasperformedthedaybeforeisencountereditwillhavetobereprimed.Useaprimerorsurfaceconditionerthatisrecommendedbythesealantmanu-facturer.Followasealantmanufacturer’spublishedrecommen-dationregardingtheuseofaprimerorsurfaceconditioner.However,itisimportanttorecognizethatanunanticipatedconditionmayariseataprojectsitethatmaybedetrimentaltogoodsealantorprimerperformanceifnotcorrectedbyspecialtreatment.Thesealantmanufacturershouldbeconsultedwhensuchconditionsexistoraresuspected.Ingeneral,aninsitutestshouldbeperformedtodeterminethepropertreatmentandsealantorprimerrecommendation,orbothforanunanticipatedcondition.Awordofcaution:manyprimerscandiscolorasubstratesurfaceoralteritsappearance.Careshouldbetakensoastonotsplashordripaprimerontoanexposedsubstratesurfaceorotherbuildingsurfaces.

16.4.6.1Application—Mostprimersareappliedasarela-tivelythinfilmthatcompletelycoversthesealantadhesionsurface.Anapplicationthatisdrippingorrunningoronewithskipsandvoidsisnotrecommendedandcanresultindeficientadhesionofthesealant.Properdispensingofaprimerisimportanttoavoidprimercontamination.Themostcommonlyencounteredtechniqueofpouringaprimerintoanopencuporbowlistheleastdesiredtechnique.Almostallsealantmanu-facturersindicatethattheprimershouldbeappliedfromaclosedcontainer,forexampleasqueezebottle,toaclothorbrush.Theclothorbrushshouldnotbedippedintoacontainerofprimer.Repeatedlydoingsocancontaminatetheprimer.Someprimers,dependingonthetypeofsubstrate,canbebrush-applied,wipedonwithacloth,orwipedonwithoneclothandwipedoffwithanother.Itisimportantthatthosewhoareapplyingaprimerbesuppliedtheproperequipmenttocontain,dispense,andapplyaprimer,andnotjustwritteninstructions.Aprimerhasashortapplicationlifeonceacontainerisopened.Asmallquantityofprimershouldbetransferredtotheapplicationcontainerforusethatday.Anyprimerremainingintheapplicationcontainerattheendofthedayshouldbediscardedsinceitmayhavebeenaffectedby

atmosphericmoistureoritssolventmayhavesubstantiallyevaporated.Theprimedsurfaceshouldbeprotectedfrombecomingcontaminated,forexample,bybeingtouchedorhandledbyworkmanwithdirtyhands.

16.4.6.2DryTime—Differentprimersrequiredifferentlengthsoftimebetweenprimerapplicationandsealantinstal-lation.Ifaprimerdoesnothaveadequatedrytime,undesirablesealantadhesionqualitymayresultorthesolventintheprimermayadverselyaffectsealantcure.Aprimernormallyrequiresaperiodoftimetodrybeforesealantapplication.Thereusuallyisamaximumtimeintervalbetweenprimerapplicationandsealantapplication,whichthesealantmanufacturercansupply.16.4.7SealantBacking—Installationofsealantbackingshouldnotbepermittedwithasharptoolsuchasaputtyknifeorscrewdriver.Asharptoolcanpuncture,crease,fold-over,orotherwisedisfigureasealantbackingmaterialresultinginpotentialdamagetothesealantbyoutgassingoranunaccept-ablechangeinsealantprofilethatisdetrimentaltojointmovement.Asmoothfacetoolshouldbeusedtoinstallitstraight,uniformly,andataconstantdepth.Adepthcontrolledrollerdeviceworkswell.Sealantbackingmustbeinstalledunderadequatecompressiontoholditin-placeinthejointopeningandtoresistthepressureappliedwhentoolinganon-sagsealantintoplace(See9).Ifnotheldin-placeadequatelyitcanfloattowardsthesurfaceofaliquid-appliedself-levelingsealant,displacingthesealantordecreasingitsrequireddepth.Itshouldbeinstalledwithoutstretching,sinceifstretcheditmayreturntoitsoriginallengththerebyaffectingsealantinstallation.Undernocircumstancesshouldsealantbackingthatistoosmallforthejointopeningbedoubleduporbraidedtogethertofittheopening.Doingsowillresultinaninadequateanddeficientsealantprofile.Additionally,itmustbeinstalledtotheproperdepthforthesealantjointdesign.Inconsistentinstallationofsealantbacking,fordepth,canresultinasealantprofilethatistoothinortoothick.Bothconditionsareunacceptableandcanresultinprematuredete-riorationofthesealantasaweatherseal.Wherecutendsofasealantbackingbutt,theyshouldbefittedtightlytogether.Thisisespeciallyimportantforahorizontaljointthatwillreceiveaself-levelingsealanttopreventitsleakagepastthesealantbacking.

16.4.8JointFiller—Afterinstallationofjointfiller,thereshouldbesufficientremainingspaceforinstallationofsealantbackingorbondbreakertapeandthesealant.Somejointfillers,forconcreteconstruction,areinstalledflushwiththefaceoftheconstruction.Theyhaveapullstripthatisthenremovedtopermitsealantbackingorbondbreakertapeinstallationpriortosealantapplication.Itshouldbeverifiedthatthereissufficientdepthafterthetearstripisremovedforsealantandrequiredaccessoryinstallation.Somejointfillersarefabricatedofamaterialthatcanfunctionassealantbackingorbondbreakerforsomesealants,therebyprecludingtheneedforthesematerials.

16.4.9BondBreaker—Installationofabondbreakertapeshouldonlybeonthesurfacewhereadhesionisnotdesired.Abondbreakertapeshouldnotlapoverontoanadjacentsealantadhesionsurface.Frequently,acoloredself-adhesivetapeisusedasabondbreaker.Thecolorassistsindeterminingthatthetapehasbeeninstalledinthecorrectlocation.Thetapeshouldbeinstalledcontinuouslywithnoskipsorvoidsintapeapplication.Ifthejointopeningvariesinwidth,twooverlap-pingtapescanbeinstalledtocontrolthewidthoftapetofittheopening.Theadhesionofabondbreakertapetosomesubstratescanbepoor.Careshouldbetakeninitsinstallationandwheninstallingsealantsoastonotmovethetapeoutofposition.

16.4.10Sealant—Toobtainpropersealantadhesiontoasubstrate,itisessentialthatthesealantcomeintodirectcontactwiththesubstrateandthatthesealantwetthesubstratesurface.Ifanyoftheseconditionsarenotmet,poorornoadhesionwillusuallyresult.Asealantshouldbeinstalledinamannerthatwillcompletelyfillthecavityformedinthejointopeningbythesubstratesandsealantbackingorbondbreaker.Somesealantapplicatorscanaccomplishthisbypushingthesealantbeadaheadofthenozzleofthegun,otherswiththenozzlebridgingthejointopening,althoughthereisincreasedriskofincompletefillingwiththisapproach.Oncesealanthasbeeninstalledinthejointopeningcavityitmustbetooled.Whensealantisinstalledinanopeningwithaporoussubstrate,thesealantmustentertheporesofthematerialifgoodadhesionistobeobtained.Anon-sagsealantisthixotropicandwillresistflowintotheporesunlessanexternalforceisapplied.Properfillingofthecavitywithsealantaccomplishesthisinpart,followedbypropersealanttooling.Sealantshouldbeinstalledinaccordancewithamanufacturer’swrittenrecommendations.16.4.11GunsandNozzles—Asealantisgenerallyappliedwithhandorair-poweredgunsfromcartridges,sausagepacks,orbulkcontainers.Bulkcontainersshouldbekepttightlyclosedexceptwhensealantisbeingremovedforuse.Theplasticnozzlesofcartridgesshouldbecuttoanopeningsizeandshapetofittheintendedjointopeningwidth,whichwillconfinesealanttothejointandaidinbuildingpressuretoforcesealantintothecavity,fillingit,andattainingintimatecontactwithjointsubstratesurfaces.Matchingthenozzlesizetothejointopeningisveryimportant.Bulkgunnozzlesareavailableinawidevarietyofsizesandshapesandshouldbeselectedtoattainthesameresultsasforplasticnozzles.Gunsandnozzlesshouldberinsedandcleanedperiodicallyduringthedayandatday’send,whenstoppingforlunch,andwhenchangingsealantcolor.Careshouldbetakentoensurethatcleaningmaterialorsolventevaporatesanddoesnotmixwiththesealant.Whenfillingagunfromacontainerairshouldnotbeintroducedintothegunwiththesealant.

16.4.12Tooling—Toolinganon-sagsealantisessentialtoforcesealantintothejointopeningandeliminateairpockets.Itshouldbeaccomplishedassoonaspossibleaftersealantapplicationandmustbecompletedbeforeskinningorcuringofthesealantbegins.Toolingalsoensurescontactofthesealantwiththesubstratesurfacesofajoint(SeeFig.10).Severaljointsealantconfigurationsarepossible,dependingontheselectionofthesealantbackingandtheshapeofthetoolsused.Forabutttypejoint,theseareclassifiedasaconcave,flush,orrecesstooledjoint(SeeFig.8).Whendeterminingthelocationofthesealantbacking,considerationshouldbegiventoareductioninsealantdepththatoccurswithaconcaveandrecesstooledjoint,andthejointdesignedaccordingly.Duringthecuring

ABCDEsealant

sealantbacking

insufficientcontactdepthfullcontactdepthsubstrate

FIG.10ImportanceofSealantBackingandSealantTooling

process,somesealantsshrink,resultinginanaturallyformedconcavitytoacuredsealantexposedsurface.Thisshouldalsobeconsideredwhenlocatingthesealantbackingtoprovidethedesiredsealantdepth.Insomecases,itmaybeadvisabletoflushtoolthesealant,sothatafterithascured,thedesiredconcavityofthecuredsealantisattained.Awater-basedorsolvent-releasesealantismostsusceptibletoshrinkagesincevolatilematerialsarelostduringthecuringprocess.Aprojectsitetrialinstallationwouldassistindeterminingthetoolingproceduretouse.Toolingisgenerallyachievedasfollows.16.4.12.1ConcaveJoint—Fig.8Aillustratesaconcavejoint,whichisthemostcommonlyusedsealantconfiguration.Dependingonthewidthofthejoint,anappropriatelyroundedtoolisusedtocontactthejointopeningedges.Asatoolismovedalongthelengthofthejointthesealantisforcedintothecavityandintointimatecontactwiththesubstratesurfaceswhileformingaconcavesurface.Thisprocedureisapplicableevenifthereareslightvariationsinjointwidth.Anexperi-encedapplicatorcansuccessfullyinstallsealantinaconcavejointwithouttheuseofmaskingtapetokeepadjacentsurfacesclean.Aconcavetooledjoint,inconjunctionwitharoundshapesealantbacking,willachieveanhourglasssealantcross-sectionshapeforgreatestmovementcapability;however,thismaynotnecessarilybetheoptimumshapeforaparticularapplication.

16.4.12.2FlushJoint—Fig.8Billustratesaflushjoint.Aflatshapetoolisused,similartoaconcavejointprofile,tostrikethesealantoffflushwiththesubstratesurface,forcingthesealantintointimatecontactwiththesubstrates.Evenwithanexperiencedapplicator,flushtoolingusuallywillrequiremaskingtapealongtheedgesofthejointopeningtokeeptheedgesandsurfacesclean.Thisisasatisfactorysealantconfigu-rationformostapplications.However,oncecuredandduringhotweather,narrowingofajointwillcauseasealantbulge,whichisnotrecommendedforhorizontaltrafficjointsandmaynotbevisuallyacceptableforotherapplications.

16.4.12.3RecessedJoint—Fig.8Cillustratesasealantpro-filewhereaconspicuousjointisdesiredthatisobtainablebyrecessingasealant.Toolingthisprofileisdifficultunlessajointisofuniformwidth,whichisdifficulttoattainwithsomematerialsandformsofconstruction.Also,jointwidthchangesmaketoolwidthsvariableandtoolingdifficulttoperform.AcurvedtoolcouldalsobeusedtogivethesealantasurfaceshapeidenticaltothatinFig.8A.Arecessedjointisapplicablewheretheouterfaceofasubstrateisirregular,suchasattheedgeofanexposedaggregateconcretepanel.Forthisandsimilarconditions,toolingrequiresmorecaretocontroldepthoftherecesssinceanirregularsubstratesurfacepreventsgaugingtooldepthonthatsurface.Forthisandsimilarapplications,recessingasealanthelpscontrolthejointwidthandgreatlyimprovesitsappearance.

16.4.12.4FilletJoint—Fig.5illustratestypicalfilletjointapplications.Toolingthisprofile,usuallywithatooldesignedfortheparticularinstallation,requiresanexperiencedapplica-tor.Thisprofileishardertocontroltoolingandthicknesssincetherearenoguidingsubstrateedgesorsurfacesforthetool.Thesurfacecanbetooledflat,convex,or,ifrequired,withaslightlyconcavesurface.Thethickness(depth)ofthesealantoversealantbackingorbondbreaker,dependingonagenericsealanttype,canbefrom3to6mm(1⁄8to1⁄4in).Dependingonapplicatorskilllevel,aminimumof6mm(1⁄4in)maybedesirabletoinsureaminimumof3mm(1⁄8in)ismaintained.Toolingshouldbecarefullyperformedtoensurethattherequiredsealantthicknessisattained.Thesealantmanufacturershouldbeconsultedforwrittenguidelinesforthethicknessoftheirsealantforaparticularfilletjointapplication.Thesealantadhesionsurfacetoasubstrateshouldbeaminimumof6mm(1⁄4in)wide.Thesealantadhesionwidthandtherequiredsealantthicknessareinterrelated.Attainingaminimumwidthof6mm(1⁄4in)mustbecoordinatedwiththeminimumthicknessrequiredbythesealantmanufacturer.Boththeminimumsealantthicknessandminimumsealantadhesionwidthmustbesatisfiedbythedesignforthejointprofile.16.4.12.5BridgeJoint—Fig.6illustratestypicalbridgesealantjointapplications.Thistypeofjointissometimesinappropriatelyreferredtoasa“bandaid”sealantjoint.Asforafilletjoint,anexperiencedsealantapplicatorisrequiredtosuccessfullyinstallanaestheticallypleasingbridgejoint.Thethickness(depth)ofthesealantoversealantbackingorbondbreaker,dependingonagenericsealanttype,canbefrom3to6mm(1⁄8to1⁄4in).Toolingshouldbecarefullyperformedtoensurethattherequiredsealantthicknessisattained.Thesealantmanufacturershouldbeconsultedforwrittenguidelinesforthethicknessoftheirsealantforaparticularbridgejointapplication.Onetechniquethatcanbeusedtocontroldepthandaestheticappearanceistouseafoamtapewithapressure

sensitiveadhesivetoformacavitywithinwhichtoinstallthesealant.Thetapeisinstalledalongbothjointedgestothefacedimensionoftherequiredjoint.Thetapeisalsoofasizetocreatetherequiredthickness(depth)ofsealant.Immediatelyaftersealanttoolingthefoamtapeiscarefullyremoved.Anothertechniqueistohaveaspecialnotchedtoolmadethatwillcreatetherequiredsealantwidthandthicknessprofilewhenthesealantistooled.Frequently,toavoidsealantsmears,maskingtapeisusedtodefinetheedgesofthesealantjoint,whichissubsequentlyremovedimmediatelyaftertoolingthesealant.Thewidthofthesealantadhesiontothesubstratesurfaceshouldbeaminimumof6mm(1⁄4in),withsomesealantmanufacturersanddesignprofessionalsrecommendingaminimumof9mm(3⁄8in).

16.4.13Tools—Typically,anappropriatelyshapedplasticormetaltoolisused.Applicatorshaveproventobemostinventiveindevelopingatoolforaparticularapplication.Tableknives,cakedecoratingspatulas,andstiffcardboardhavebeenusedsuccessfullytotoolasealantjoint.Mostsealantmanufacturersandapplicatorsrecommendandusedrytools,whichmaybesurface-treatedwithapermanentcoatingtopreventadhesionofthesealant.Toolsshouldbecleanedperiodicallytopreventbuild-upofoldsealantandespeciallywhenchangingcolorstopreventcontamination.

16.4.14ToolingLiquid—Atoolshouldbeuseddrytoapplythesealantandtoprecludeanypossibilityofsubstratecon-taminationbyatoolingliquid.However,wherepermittedbythesealantmanufacturer,atoolcanbeusedwettedbyanapprovedliquid.Dippingatoolincertainliquidsdecreasesadhesionofasealanttothetool.Aliquidproposedforusewithaparticularsealantshouldfirstbetestedandapprovedforusebythesealantmanufacturer.Theuseofsometoolingliquidsmaycauseasurfacediscolorationoftheexposedsubstratesurfacealongtheedgesofajointorattractdusttothestilltackysealantsurfacewhereitcanchangethesealantcolor.Itisadvisabletotestthejointsubstratematerialwiththeproposedtoolingliquidtodetermineiftherewillbeanypermanentdiscolorationofthesubstrate.Whenusingatoolingliquid,careshouldbetakentoensurethatitdoesnotcontactajointsubstratesurfacepriortosealantapplication.Thiscanoccurespeciallywithverticalsealantjoints,wheretheliquidcandripdownwardandpotentiallycontaminatethesubstratesurfaces.Ifasubstrateiscontaminatedwithatoolingliquid,sealantadhesiontothesubstrateisusuallyadverselyaffected.16.4.15RemovalofMaskingTape—Assoonasasealanthasbeentooledtothedesiredshapethemaskingtapeshouldbecarefullyremoved.Waitinguntilasealanthasstartedtoskinoverandcurewillusuallymakeremovalmoredifficultandcancausedamagetothesealantjointsurface.Leavingmaskingtapein-placeforanextendedperiodoftimecanalsoresultinverydifficulttapeandadhesiveremovalandinsomeinstancesdamagetothefinishofcertainsubstrates.

16.4.16Cleanup—Cleanupofhands,tools,andotheritemsiseasiesttoaccomplishassoonaspossible,whilethesealantisfreshanduncured.Awater-basedsealantiscleanedfromhandsandtoolswithwatertowhichaliquidcleanercanbeadded,ifnecessary.Othertypesofsealantrequireasolventsuchastoluene,xylene,methylethylketone(MEK),acetone,ormineralspiritsforcleanup.Solventsdescribedaretoxicandflammable.Thesolventmanufacturer’swrittenprecautionsshouldbeobservedduringstorage,use,anddisposalofsolvents.Cloths,rags,orpaperwipesthatareusedwithsolventsarealwaysafirehazardandshouldbedisposedofinasafemanner.Sealantmanufacturerscanprovidecleanuprecommendations.Gunsandtoolsshouldbecleaneddailyandbetweensealantcolorchanges.Itisnotadvisabletocleaninadvertentlyspilledsealantfromporoussurfacesusingasolvent.Solventswilltendtodrivethesealantdeeperintotheporoussubstrateandmayleaveapermanentstainonthesubstrate.Scrape,wipe,orscrubthespillusingdrytoolsorrags.Alternatively,ifaseriousconsideration,tarpsorotherbarrierscanbeinstalledtopreventothersurfacesfrombecom-ingcontaminatedwithsealantsmearsordroppings.16.5PrecuredSealant:

16.5.1General—Thefollowingsectionsgenerallydescribethevariousproceduresassociatedwithatypicalliquid-appliedadhesive-sealantandprecuredsealantinstallation.Eachinstal-lationshouldbeevaluatedforanychangesoradditionstotheseproceduresrequiredbythatparticularapplication.

16.5.2Adhesive-SealantAdhesionTest—Theadhesive-sealantthatwillbeusedtoadheretheprecuredsealanttothesubstrateshouldbeverifiedforadhesionandcompatibilitywiththesubstrate.Adhesioncanbedeterminedwithsmall-scalesamplesinalaboratoryorinsitusimilartoasdescribedin5.3.1.Compatibilitycanbedeterminedasdescribedin5.4.1.16.5.3JointPreparation—Frequently,aprecuredsealantisusedtorepairorreplaceafailedliquid-appliedsealantjoint.Occasionally,thefailedsealantwillprotrudefromorbefallingoutofthejointopeningrepresentinganobstacletoadequateplacementoftheprecuredsealant.Also,previousapplicationsofliquid-appliedsealantasaremedialrepairmaycontaminatethesubstratesurfacesadjacenttothejointopening.Removaloftheseexcessmaterialsisusuallyrequiredtofacilitateadhesive-sealantandprecuredsealantapplication.Attimes,thesubstratecanbeinadamagedconditionduetofailureofthesealantortoenvironmentaleffectsfromnormalweathering.Damageshouldberepairedsothatanacceptablesubstratesurfaceisavailablefortheadhesive-sealant.

16.5.4SurfaceCleaning—Onceremovalofexcesssealantorothermaterialshasoccurredandthesubstratesurfaceisinanacceptablecondition,thesubstrateshouldbecleanedtopermitproperapplicationoftheadhesive-sealant.Cleaningcanbeconductedusingmaterialsdescribedin7andproceduresdescribedin16.4.4.

16.5.5Primer—Ifaprimerisrequiredtoobtainadequateadhesionoftheadhesive-sealantitcanbeappliedusingmaterialsdescribedin8andproceduresdescribedin16.4.6.16.5.6BondBreaker—Occasionally,abondbreakerisin-stalledoverapreviouslyinstalledandusuallyfailedliquid-appliedsealanttoprovideabarrierbetweenthatsealantandtheprecuredsealant.Thisisdonetoprecludeincompatibilityfromoccurringbetweenthetwosealantsandadverselyaffectingtheprecuredsealant.Abondbreakerisalsousedtoestablishtheunadheredlengthoftheprecuredsealantneededtoaccommo-datetheexpectedmovement.

16.5.7MaskingTape—Theinstallationofmaskingtape

(See16.4.5)maybenecessarytopreventsealantfrombeingappliedorinadvertentlycomingintocontactwithvisiblesubstratesurfaces.Maskingtapeisappliedtothesubstrateatthelocationwheretheedgeoftheprecuredsealantwillbelocated.

16.5.8Adhesive-Sealant—Abeadofadhesive-sealantisappliedalongbothsidesofthejointwheretheprecuredsealantwillbeadheredtothesubstrate.Thebeadshouldbeappliedapproximately6mm(1⁄4in.)inwardfromtheedgeofthemaskingtape.Sizeoftheappliedadhesive-sealantbeadisdependentonthedegreeofroughnessofthesubstratesurfaceandthedesiredinstalledwidthofadhesive-sealant.Thesizeofthebeadisusuallydeterminedbyevaluatingatestmockup.Precuredsealantmanufacturersgenerallyrecommendamini-muminstalledadhesive-sealantwidthofatleast6to9mm(1⁄4to3⁄8in.).Thiscanvarydependingonaparticularapplication.16.5.9PrecuredSealantShape:

16.5.9.1Extruded—Ingeneral,dependingonenvironmen-talconditions,aprecuredsealantshouldbeinstalledassoonaspossible.Iftheadhesive-sealantskinsoverorbecomestack-free,inadequateornoadhesionoftheprecuredsealanttotheadhesive-sealantwillresult(SeeFig.3).Theprecuredsealantispressedintotheappliedbeadsofadhesive-sealantwettingtheprecuredsealantandsubstratesurfaces.

16.5.9.2Molded—Withamoldedshape,theadhesive-sealantbeads,dependingontheparticularapplication,canbeappliedtothesubstrateortothemoldedshape.Ingeneral,dependingonenvironmentalconditions,themoldedshapeshouldbeinstalledassoonaspossible.Iftheadhesive-sealantskinsoverorbecomestack-free,inadequateornoadhesionoftheadhesive-sealanttothemoldedshapewilloccur.Themoldedshapeispressedintotheappliedbeadsofadhesive-sealantwettingthemoldedshapeandsubstratesurfaces.

16.5.10Tools—Toassistinpressingtheprecuredsealantintotheappliedadhesive-sealantbeadsatoolsuchasarollerisoftenusedandisrecommended.Arollerwillpermitmoreconsistentpressuretobeappliedtoensureintimateanduniformadhesive-sealantcontactwiththesubstrateandpre-curedsealant.

16.5.11Cleanup—Afterinstallation(See16.4.16),theex-trudedexcessadhesive-sealantwillhaveaccumulatedonthemaskingtape.Maskingtaperemovalshouldoccurbeforetheadhesive-sealanthasstartedtocuretopreventstringingofthesealantandtomakecleanupeasiertoaccomplish.

17.SealantJointMaintenance

17.1Often,periodicmaintenanceofasealantjointisnotperformed.Itcannotbestatedenoughthatasealantjointrequiresmaintenance,especiallyforahorizontalapplication,justasforothercomponentsofabuilding.Abuildingownerormanagershouldhaveperiodicinspectionsperformedtoiden-tifyareaswhereremedialsealantrepairormaintenanceworkisrequired.Foregoingperiodicmaintenancewillusuallyresultinadditionalsealantjointfailure,hiddendeteriorationofmateri-als,andanacceleratedfailureofthesealantweatherseal

function.Manycommunities,atleastformulti-storystructures,requireaperiodicfacadeinspectionatanintervalofabout5years.Thisperiodiccodeorregulationrequiredinspectionshouldbeusedtoalsohelpidentifysealantjointconditionsneedingrepair,althoughsomeofthesefaçadeinspectionsdonotinvolvetheentirefaçade–justselectedareas.Tofacilitaterepairandmaintenance,thebuildingownerormanagershouldmaintainadequaterecordsrelatedtothesealantjointsonoradjacenttothebuilding,includinginformationsuchastheoriginalsealanttype,jointcleaningandprimingrequirements,requiredjointaccessories,andanyotherinformationimportanttomaintenanceandrepair.

18.Certification,Marking,Shipping,Preservation,and

Safety18.1General—Informationfromthefollowinggeneralguidelines,appropriatelymodifiedwhererequiredforaspe-cificapplication,shouldbeincorporatedintothemethodofprocurementofthevariousmaterialsrequiredforasealantinstallation.

18.2Certification—Certificationfromthesealantmanufac-turershouldbeavailablebeforethedeliveryofmaterialtotheprojectsite,attestingthatthesealantandprimermaterialsconformtothespecificationrequirements.Certificationshouldincludecompletetestresultsperformedonrepresentativematerials(sameformulation)withinatwelve-monthperiodprecedingthedateofsubmissionofcertificationtothepur-chaser.Testdatamorethantwelvemonthsoldmaybesubmittedprovidedthesealantmanufacturerindicatesinthecertificationthatthetestedsealantandprimerhavenotchangedinformulaormanufacturesufficienttoproduceadifferentresult.

18.3PackageMarkingandShipping—Materialshouldbedeliveredtotheprojectsiteinoriginalsealedcontainers.Acontainershouldbemarkedwiththeappropriateinformation,includingsupplier,materialnameandnumber,andspecifica-tionnumbertowhichitconforms.Additionally,forasealantandprimer,color,expirationperiod(shelflife),andpotlifeandcuringtimeatstandardlaboratorytestconditions(whenapplicable)shouldbeindicated.Amulti-componentsealantshouldalsohavemixingandhandlinginstructionsclearlyindicated.

18.4Preservation—Materialshouldbestoredandprotectedinaccordancewithamanufacturer’sprintedinstructions.Anoutdatedmaterialshouldnotbeusedunlessrecertifiedbythemanufacturerassuitableforuse.

18.5Safety—Ifpotentiallyhazardousorregulatedmaterialsarenecessary,specialprecautionsandhandlinganddisposalrecommendationsbythemanufacturershouldbefollowed.19.Keywords

19.1bondbreaker;guide;jointaccessories;jointfiller;precuredsealant,primer;sealant;sealantbacking;sealantdesign;sealantgeometry;sealantinstallation;sealantjoint

APPENDIXES

(NonmandatoryInformation)

X1.TESTMETHODSTODETERMINESEALANTADHESIONCHARACTERISTICSINSITU

X1.1MethodA,Field-AppliedSealantJointHandPull

Tab

X1.1.1Scope

X1.1.1.1Thisadhesiontestisasimplescreeningprocedureforafieldappliedsealantthatmayhelpdetectfieldapplicationproblems,suchasimpropersubstratecleaning,useofanimproperprimer,poorprimerapplication,improperjointconfiguration,andmanyoftheotherfieldapplicationproblemsthatcanaffectadhesion.Asacheckforadhesion,thissimplehandpulltestisperformedattheprojectsiteafterasealanthascured(usuallywithin7to21days).Thistestisdestructivetoaportionofthesealantjoint,whichfollowingtestingisrepaired.Itisrecommendedthataminimumofonetestbeperformedforeach305m(1,000ft)ofeachtypeofsealantjoint.

X1.1.2Apparatus

X1.1.2.1Knife—Ofappropriatelengthwithathinsharpblade.

X1.1.2.2Sealant—Samesealantmaterialasisbeingtested.X1.1.2.3Spatula—Asuitableitemtopermittoolingofthesealant.

X1.1.3Procedure

X1.1.3.1Makeaknifecuthorizontallyacrossthewidthofthesealantjointfromonesubstrateofthejointtotheother.X1.1.3.2Maketwoverticalcuts(downwardstartingatthehorizontalcut)approximately75mm(3-in.)long,atbothsidesofthejointnexttothesubstrates.

X1.1.3.3Graspthe75mm(3-in.)sealanttabfirmly25mm(1in)fromitsbondededgeandpullata90degreeangle(Fig.X1.1).

X1.1.4Results

X1.1.4.1Ifsubstrateadhesionisacceptable,thesealantshouldtearcohesivelywithinitselforelongatetoamanufac-turerdeterminedextensionvaluefromthe25mm(1in)gaugelengthindicatedinX1.1.3.3,beforereleasingfromeithersubstrateadhesively.

X1.1.5RepairofSealantatAdhesionTestArea

X1.1.5.1Repairthesealantpulledfromthetestareabyapplyingnewsealanttothetestarea.Assuminggoodadhesionwasobtained,usethesameapplicationproceduretorepairtheareaaswasusedoriginallyforthejoint.Careshouldbetakentoensurethattheoriginalsealantsurfacesarecleanandthatthenewsealantisincontactwiththeoriginalsealant.X1.1.6Report

X1.1.6.1Filetheadhesiontestnumber,date,sealantlotnumber(s),testresults(cohesiveoradhesivefailure),andotherpertinentinformationinaqualitycontroldocumentforfuturereference.

X1.2MethodB,ExposedSurfaceFinishHandPullTabX1.2.1Scope

X1.2.1.1Thisisasimplescreeningtestthatisperformedonaflatsurface.ItisapplicabletothosesituationswhereitisdifficultornotpossibletotestasealantjointforadhesionbyMethodA.Testforadhesiononanexposedsurfacefinishthatisthesamefinishasthesubstratetowhichthesealantisadhered.

X1.2.2Apparatus

X1.2.2.1Substrate—Samefinishasinstalledfortheproject.Thismethodcanbeperformedonasurfaceonabuildingoronasmall-scalesampleremovedfromabuilding.

X1.2.2.2Primer—Asusedforthejoint,ifrequired.

X1.2.2.3BondbreakerTape—PolyethyleneorTeflonself-adhesivetape.

X1.2.2.4Sealant—Samesealantmaterialasinstalledinthesealantjoint.

X1.2.2.5Spatula—Asuitableitemtopermittoolingofthesealant.

X1.2.2.6Knife—Ofappropriatelengthwithathinsharpblade.

X1.2.3Procedure

X1.2.3.1Cleanand,ifrequired,primetheadhesionsurfacefollowingtheproject-specificrecommendedprocedures.

X1.2.3.2Placeapieceofbondbreakertapeonthesurface.

FIG.X1.1HandPullTest

X1.2.3.3Applyabeadofsealantapproximately200mm(4-in.)long,25mm(1-in.)wideand3mm(1⁄8-in.)thick.Atleast50mm(2-in.)ofthesealantshouldbeappliedoverthebondbreakertape(Fig.X1.2.A).

X1.2.3.4Toolthesealanttoensuregoodsealantcontactwiththeadhesionsurface.

X1.2.3.5Aftercure(usuallywithin7to21days),liftthesealanttaboffthebondbreakertape,holdthesealanttabatabout25mm(1in.)fromtheadherededge,andpullfirmlyata90degreeangle.X1.2.4Results

X1.2.4.1Ifsubstrateadhesionisacceptable,thesealantwilltearcohesively(Fig.X1.2B),withnoadhesivefailurefromthesubstrate(Fig.X1.2C),orelongatetoamanufacturerdeter-minedextensionvaluefromthe25mm(1in)gaugelengthindicatedinX1.2.3.5,withnoadhesivefailure.X1.2.5Report

X1.2.5.1Filetheadhesiontestnumber,date,sealantlotnumber(s),testresults(cohesiveoradhesivefailure),andotherpertinentinformationinaqualitycontroldocumentforfuturereference.

X1.3MethodC,Field-AppliedSealantJointHandPull

Flap

X1.3.1Scope

X1.3.1.1Thisadhesiontestisasimplescreeningprocedure(similartoX1.1,MethodA)forafieldappliedsealantthatmayhelpdetectfieldapplicationproblems,suchasimpropersubstratecleaning,useofanimproperprimer,poorprimerapplication,improperjointconfiguration,andmanyoftheotherfieldapplicationproblemsthatcanaffectadhesion.Asacheckforadhesion,thissimplehandpulltestisperformedattheprojectsiteafterasealanthascured(usuallywithin7to21days).Thistestisdestructivetoaportionofthesealantjoint,whichfollowingtestingisrepaired.X1.3.2Apparatus

X1.3.2.1Knife—Ofappropriatelengthwithathinsharpblade.

X1.3.2.2Sealant—Samesealantmaterialasisbeingtested.X1.3.2.3Spatula—Asuitableitemtopermittoolingofthesealant.

X1.3.3Procedure

X1.3.3.1Makeaknifecuthorizontallyacrossthewidthofthesealantjointfromonesubstrateofthejointtotheother.

X1.3.3.2Makeoneverticalcut(downwardstartingatthehorizontalcut)approximately75mm(3-in.)long,alongonesideofthejointnexttothesubstrate.

X1.3.3.3Makeasecondknifecuthorizontallyacrossthewidthofthesealantjointfromonesubstrateofthejointtotheotherattheoppositeendofthe75mm(3in.)cut.

X1.3.3.4Graspthe75mm(3-in.)sealantflapfirmlyfromitsbondededgeandpullata90degreeangle.X1.3.4Results

X1.3.4.1Ifsubstrateadhesionisacceptable,thesealantshouldtearcohesivelywithinitselforelongatetoamanufac-turerdeterminedextensionvaluebeforereleasingfromthesubstrateadhesively.

X1.3.5RepairofSealantatAdhesionTestArea

X1.3.5.1Repairthesealantpulledfromthetestareabyapplyingnewsealanttothetestarea.Assuminggoodadhesionwasobtained,usethesameapplicationproceduretorepairtheareaaswasusedoriginallyforthejoint.Careshouldbetakentoensurethattheoriginalsealantsurfacesarecleanandthatthenewsealantisincontactwiththeoriginalsealant.X1.3.6Report

X1.3.6.1Filetheadhesiontestnumber,date,sealantlotnumber(s),testresults(cohesiveoradhesivefailure),andotherpertinentinformationinaqualitycontroldocumentforfuturereference.

X1.4MethodD,WaterImmersionX1.4.1Scope

X1.4.1.1BothMethodAandBcanincludeawaterimmer-sionandanotherpullteststepwithappropriateuseofinsituwatercontainingdevices.IfthesampleforMethodAandBdidnotfailadhesively,itcanbeusedforthisMethod.X1.4.2Apparatus

X1.4.2.1Container—Asuitablesizethatcanbeattachedinsitutothesurfaceandcapableofimmersingthesamplewhilecontainingwaterfortheperiodofimmersion.Ifasmall-scalesamplefromMethodBisusedthecontainershouldbeasuitablesizeforimmersionofthesample.X1.4.3Procedure

X1.4.3.1FollowingsuccessfulcompletionofMethodA,B,orCthesampleisimmersedinwater.AnalternateprocedureforMethodAandCistoimmersethesamplepriortoperformingapulltaborflaptest.Thepulltestisthenperformedonceduringthismethod.Ifperformedonabuilding

FIG.X1.2HandPullTest

surface,environmentalconditionsmayrequireprotectionofthewaterimmersiondevicetoprecludefreezingofthewateroritsheatingtohightemperature.Thespecifyingauthorityshouldestablishthewatertemperature.Forexample,anacceptablerangecouldbe2266°C(72610°F).

X1.4.3.2Thesampleisimmersedforaperiodoftimeasdeterminedbythespecifyingauthority,forexample1,3,or7days.

X1.4.3.3Afterimmersionforthespecifiedtimeperiod,patdry,andimmediatelyliftthesealanttaborflapand,asdescribedintheapplicableprocedure,pullfirmlyata90degreeangle.

X1.4.4Results

X1.4.4.1Ifsubstrateadhesionisacceptable,thesealantwilltearcohesivelywithnoadhesivefailurefromthesubstrateorelongatetoamanufacturerdeterminedextensionvaluewithnoadhesivefailure.X1.4.5Report

X1.4.5.1Filetheadhesiontestnumber,date,sealantlotnumber(s),testresults(cohesiveoradhesivefailure),andotherpertinentinformationinaqualitycontroldocumentforfuturereference.

X2.GeneralIndextoTopicsandHeadingsasListedintheGuide

X2.1Index

1.2.2.13.3.13.23.2.13.2.23.2.33.2.43.2.54.5.5.15.25.2.15.35.3.15.45.4.15.55.5.15.65.6.15.75.7.15.85.8.15.8.25.8.36.6.16.26.2.16.2.26.2.37.7.17.27.2.17.2.28.8.18.28.2.18.2.28.3

Scope

ReferencedDocumentsASTMStandardsTerminologyDefinitionsDefinitionsofTermsSpecifictoThisStandarddurabilitydurabilitylimitprecuredsealantprematuredeteriorationservicelifeSignificanceandUse

GeneralConsiderationsGeneralDurabilityDurabilityTestingAdhesionAdhesionTestingCompatibilityCompatibilityTestingSubstrateStainingStainTestingSealantColorChangeColorChangeTestingLiquidImmersionLiquidImmersionResistanceTestingEnvironmentalInfluencesLowTemperatureHighTemperatureMoistureSubstrateGeneralTypesPorousNon-PorousEIFSCleanerGeneralProcedurePorousSubstrateNon-PorousSubstratePrimerGeneralMaterialsColorClarityApplication8.3.18.3.28.3.39.9.19.29.2.19.2.29.39.3.19.3.29.3.39.3.49.49.4.19.4.29.4.39.59.5.19.5.29.5.310.10.110.211.11.111.211.2.112.12.112.212.312.3.112.3.212.412.4.112.4.1.112.4.1.212.4.1.312.4.212.4.312.4.412.4.512.4.612.4.712.512.5.112.5.212.5.312.5.412.5.512.5.5.1

GeneralPorousSubstrateNon-PorousSubstrateSealantBackingGeneralFunctionNormalTemporaryJointSealMaterialOpenCellFoamClosedCellFoamBicellularFoamOthersShapeandFormRoundRectilinearTriangularApplicationVerticallyOrientedSurfaceHorizontalSurfaceTemporaryJointSealJointFillerGeneralFunctionBondBreakerGeneralCompatibilityandAdhesionTestingAdhesionTestMethodLiquid-AppliedSealantGeneralCureTimeTypeSingle-ComponentMulti-ComponentFormulationModulusLowMediumHighMovementCapabilityNon-SagSelf-LevelingExtrudabilityConditioningPaintingMovement-During-CureDamagePotentialPotentialCausesTestMethodLimitationsSealanttypeandCureRateDamageassessmentGeneral12.5.5.2PhysicalObservation12.5.5.3LaboratoryTests12.5.6JointMovement12.5.6.1General12.5.6.2UseofaMock-up12.5.6.3ThermalMovement12.5.6.4MovementCombinations12.5.7ReducingMovement-During-Cure12.5.7.1General12.5.7.2SealantCure12.5.7.3SealantBacking12.5.7.4JointMovement12.5.7.5PrecuredSealant13.PrecuredSealant13.1General13.2Type13.3MovementCapability13.4EnvironmentalConditions13.5Color13.6Painting14.SealantJoints14.1Liquid-Applied14.1.1General14.1.2Width14.1.3Depth14.1.3.1PorousSubstrate14.1.3.2Non-PorousSubstrate14.1.4SealantJointType14.1.4.1ConcaveButtJoint14.1.4.2FlushButtJoint14.1.4.3RecessedButtJoint14.1.4.4FilletJoint14.1.4.5BridgeJoint14.1.5SealantJointApplication14.1.5.1VerticalSurface14.1.5.2SlopingSurface14.1.5.3HorizontalSurface14.1.5.4LiquidImmersion14.2PrecuredSealant14.2.1ExtrudedShape14.2.2MoldedShape15.DesigningaSealantJointforMovement15.1General15.2PerformanceFactors15.3Movements15.3.1ThermalMovement15.4Tolerances16.SealantInstallation16.1General16.2EnvironmentalConditions16.3RemedialSealantWork16.4

Liquid-AppliedSealant16.4.1General16.4.2JointOpening16.4.2.1Inspection16.4.2.2Substrate16.4.3SealantAdhesionTests16.4.3.1LaboratoryTest16.4.3.2InsituTest16.4.4JointPreparation16.4.4.1SurfaceCleaning16.4.4.2PorousMaterial16.4.4.3Non-PorousMaterial16.4.5MaskingTape16.4.6Primer16.4.6.1Application16.4.6.2DryTime16.4.7SealantBacking16.4.8JointFiller16.4.9BondBreaker16.4.10Sealant16.4.11GunsandNozzles16.4.12Tooling16.4.12.1ConcaveJoint16.4.12.2FlushJoint16.4.12.3RecessedJoint16.4.12.4FilletJoint16.4.12.5BridgeJoint16.4.13Tools16.4.14ToolingLiquid16.4.15RemovalofMaskingTape16.4.16Cleanup16.5PrecuredSealant16.5.1General16.5.2Adhesive-SealantAdhesionTest16.5.3JointPreparation16.5.4SurfaceCleaning16.5.5Primer16.5.6BondBreaker16.5.7MaskingTape16.5.8Adhesive-Sealant16.5.9PrecuredSealantShape16.5.9.1Extruded16.5.9.2Molded16.5.10Tools16.5.11Cleanup17.SealantJointMaintenance

18.Certification,Marking,Shipping,Preservation,andSafety18.1General18.2Certification18.3PackagingMarkingandShipping18.4Preservation18.5Safety19.

Keywords

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