汽车电器试验标准

SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.QUESTIONSREGARDINGTHISDOCUMENT:(412)772-8512FAX:(412)776-0243TOPLACEADOCUMENTORDER;(412)776-4970FAX:(412)776-0790SAEWEBADDRESShttp://www.sae.orgCopyright1994SocietyofAutomotiveEngineers,Inc.Allrightsreserved.PrintedinU.S.A.SURFACEVEHICLE400CommonwealthDrive,Warrendale,PA15096-0001RECOMMENDEDPRACTICESubmittedforrecognitionasanAmericanNationalStandardJ1455REV.AUG94Issued1988-01Revised1994-08SupersedingJ1455JAN88(R)JOINTSAE/TMCRECOMMENDEDENVIRONMENTALPRACTICESFORELECTRONICEQUIPMENTDESIGN(HEAVY-DUTYTRUCKS)1.Scope—Theclimatic,dynamic,andelectricalenvironmentsfromnaturalandvehicle-inducedsourcesthatinfluencetheperformanceandreliabilityofvehicleandtractor/trailerelectroniccomponents,areincludedinthisSAERecommendedPractice.Testmethodsthatcanbeusedtosimulatetheseenvironmentalconditionsarealsoincluded.ThisinformationisapplicabletodieselpowertrucksinClasses6,7,and8.1.1Purpose—Thisguidelineisintendedtoaidthedesignerofautomotiveelectronicsystemsandcomponentsbyprovidingmaterialthatmaybeusedtodevelopenvironmentaldesigngoals.2.References2.1ApplicablePublications—Thefollowingpublicationsformapartofthespecificationtotheextentspecifiedherein.UnlessotherwiseindicatedthelatestrevisionofSAEpublicationsshallapply.2.1.1SAEPUBLICATIONS—AvailablefromSAE,400CommonwealthDrive,Warrendale,PA15096-0001.SAEJ400—TestforChipResistanceofSurfaceCoatingsSAEJ726—AirCleanerTestCodeSAEJ1113NEWDRAFT—ElectromagneticSusceptibilityProceduresforVehicleComponents(ExceptAircraft)SAEJ1211—RecommendedEnvironmentalPracticesforElectronicEquipmentDesignSAEJ1812—FunctionPerformanceStatusClassificationforEMCSusceptibilityTestingofAutomotiveElectronicandElectricalDevices2.1.2ASTMPUBLICATIONS—AvailablefromASTM,100BarrHarborDrive,WestConshohocken,PA19428-2959.ASTMC150-84—SpecificationforPortlandCementASTMB117-73—StandardMethodofSaltSpray(Fog)TestingASTMD775-80—MethodforDropTestforLoadedBoxesASTMD880-79—MethodforInclineImpactTestforShippingContainers2.1.3MILITARYPUBLICATIONS—AvailablefromU.S.Government,DODSSP,SubscriptionServiceDivision,Building4D,700RobbinsAvenue,Philadelphia,PA19111-5094.MIL-STD-810D,19July1983—EnvironmentalTestMethodsandEngineeringGuidelinesMIL-STD-202F,01April1980—TestMethodsforElectronicandElectricalComponentPartsSAEJ1455RevisedAUG94-2-2.1.4RELATEDPUBLICATIONS—Thefollowingpublicationsareprovidedforinformationpurposesonlyandarenotarequiredpartofthisdocument.TAPPIT801-83TAPPIT802-813.Application3.1EnvironmentalDataandTestMethodValidity—TheinformationincludedinthefollowingsectionsisbasedupontestresultsachievedbymajorNorthAmericantruckmanufacturersandcomponentequipmentsuppliers.Operatingextremesweremeasuredattestinstallationsnormallyusedbymanufacturerstosimulateenvironmentalextremesforvehiclesandoriginalequipmentcomponents.Theyareofferedasadesignstartingpoint.Generally,theycannotbeuseddirectlyasasetofoperatingspecificationsbecausesomeenvironmentalconditionsmaychangesignificantlywithrelativelyminorphysicallocationchanges.Thisisparticularlytrueofvibration,enginecompartmenttemperature,andelectromagneticcompatibility.Actualmeasurementsshouldbemadeasearlyaspracticabletoverifythesepreliminarydesignbaselines.Theproposedtestmethodsarecurrentlybeingusedforlaboratorysimulationorareconsideredtobearealisticapproachtoenvironmentaldesignvalidation.Theyarenotintendedtoreplaceactualoperationaltestsunderadverseconditions.Therecommendedmethodsdescribestandardcyclesforeachtypeoftest.Thedesignermustspecifythenumberofcyclesoverwhichthevehicleelectroniccomponentsshouldbetested.Thenumberofcycleswillvarydependinguponequipment,location,andfunction.Whilethestandardtestcycleisrepresentativeofanactualshorttermenvironmentalcycle,noattemptismadetoequatethiscycletoanaccelerationfactorforreliabilityordurability.Theseconsiderationsarebeyondthescopeofthisdocument.3.2OrganizationofTestMethodsandEnvironmentalExtremesInformation3.2.1ThedatapresentedinthisdocumentarecontainedinSections4and5.Section4,EnvironmentalFactorsandTestMethods,describesthethirteencharacteristicsoftheexpectedenvironmentthathaveanimpactontheperformanceandreliabilityoftruckandbuselectronicsystems.Thesedescriptionsaretitled:a.Temperatureb.Humidityc.SaltSprayAtmosphered.ImmersionandSplash(Water,Chemicals,andOils)e.SteamCleaningandPressureWashingf.Fungusg.Dust,Sand,andGravelBombardmenth.Altitudei.MechanicalVibrationj.MechanicalShockk.GeneralHeavy-DutyTruckElectricalEnvironmentl.SteadyStateElectricalCharacteristicsm.Transient,Noise,andElectrostaticCharacteristicsn.ElectromagneticCompatibility/ElectromagneticInterferenceTheyareorganizedtocoverthreefacetsofeachfactor:1.Definitionofthefactor2.Descriptionofitseffectoncontrol,performance,andlong-termreliability3.AreviewofproposedtestmethodsforsimulatingenvironmentalstressSAEJ1455RevisedAUG94-3-3.2.2INSECTION5a.Underhood1.Engine(LowerPortion)2.Engine(UpperPortion)3.Bulkheadb.Interior(cab)1.Floor2.InstrumentPanel3.HeadLiner4.InsideDoorsc.Interior(aftofcab)1.BunkArea2.StorageCompartmentd.Chassis1.Forward2.Reare.ExteriorofCab1.UnderFloor2.Rear3.Top4.Doors3.3CombinedEnvironments—Thevehicleenvironmentconsistsofmanynaturalandinducedfactors.Combinationsofthesefactorsarepresentsimultaneously.Insomecases,theeffectofacombinationofthesefactorsismoreseriousthantheeffectofexposingsamplestoeachenvironmentalfactorinseries.Forexample,thesuggestedtestmethodforhumidityincludeshigh-andlow-temperatureexposure.Thiscombinedenvironmentaltestisimportanttovehicleelectroniccomponentswhenproperoperationisdependentonsealintegrity.Temperatureandvibrationisasecondcombinedenvironmentaltestmethodthatcanbesignificanttocomponents.Duringdesignanalysisacarefulstudyshouldbemadetodeterminethepossibilityofdesignsusceptibilitytoacombinationofenvironmentalfactorsthatcouldoccurattheplannedmountinglocation.Ifthepossibilityofsusceptibilityexists,acombinedenvironmentaltestshouldbeconsidered.3.4TestSequence—Theoptimumtestsequenceisacompromisebetweentwoconsiderations:3.4.1Theorderinwhichtheenvironmentalexposureswilloccurinoperationaluse.3.4.2Asequencethatwillcreateatotalstressonthesamplethatisrepresentativeofoperationstress.Thefirstconsiderationisimpossibletoimplementinvehicletestingsinceexposuresoccurinarandomorder.Thesecondconsiderationpromptsthetestdesignertoplacethemostsevereenvironmentslast.Manysequencesthathavebeensuccessfulfollowthisgeneralphilosophy,exceptthatthetemperaturecycleisplacedorperformedfirstinordertoconditionthesamplemechanically.SAEJ1455RevisedAUG94-4-4.EnvironmentalFactorsandTestMethods4.1Temperature4.1.1DEFINITION—Thermalfactorsareprobablythemostpervasiveenvironmentalhazardtovehicleelectroniccomponents.Sourcesfortemperatureextremesandvariationsinclude:4.1.1.1Thevehicle'sclimaticenvironment,includingthediumalandseasonalcycles—Variationsinclimatebygeographicallocationmustbeconsidered.Inthemostadversecase,thevehiclethatspendsthewinterinCanadamaybedriveninthesummerintheArizonadesert.Temperaturevariationsduetothissourcerangefrom-54to+85°C(-65to+185°F).4.1.1.2Heatsourcesandsinksgeneratedbythevehicle'soperation—Themajorsourcesaretheengineanddrivetraincomponents,includingthebrakesystem.Widevariationsarefoundduringoperation.Forinstance,temperaturesonthesurfaceoftheenginecanrangefromthecoolingsystem88°C(190°F)tothesurfaceattheexhaustsystemat816°C(1500°F).Thiscategoryalsoincludesconduction,convection,andradiationofheatbecauseofthevariousmodesofthevehicle'soperation.4.1.1.3Self-heatingoftheequipmentduetoitsinternaldissipation—Adesignreviewoftheworstcasecombinationofpeakambienttemperature(see4.1.1.1and4.1.1.2),minimizedheatflowawayfromtheequipment,andpeak-appliedsteady-statevoltageshouldbeconducted.4.1.1.4Vehicleoperationalmodeandactualmountinglocation—Measurementsshouldbemadeattheactualmountingsiteduringthefollowingvehicularconditionswhiletheyaresubjectedtothemaximumheatgeneratedbyadjacentequipment,andwhiletheyareatthemaximumambientenvironment:a.Enginestartb.Engineidlec.Enginehighspeedd.Engineturnoff(Priorhistoryimportant.)e.Variousengine/roadconditions4.1.1.5Ambientconditionsbeforeinstallationduetostorageandtransportationextremes—Shipmentinunheatedaircraftcargocompartmentsmaylowertheminimumstorage(nonoperating)temperatureto-50°C(-58°F).Thethermalenvironmentalconditionsthatarearesultoftheseconditionscanbedividedintothreecategories:a.Extremes-Theultimateupperandlowertemperaturestheequipmentisexpectedtoexperience.b.Cycling-Thecumulativeeffectsoftemperaturecyclingwithinthelimitsoftheextremes.c.Shock-Rapidchangeoftemperature.Figure1illustratesoneformofvehicleoperationthatinducesthermalshockandisderivedfromanactualroadtestoftwovehicles.Thermalshockisalsoinducedwhenvehicleelectroniccomponentryatelevatedtemperatureisexposedtosuddenrainorroadsplash,orwhenitismovedfromaheatedshelterintoalow(-40°C/-40°F)ambienttemperatureenvironment.SAEJ1455RevisedAUG94-5-FIGURE1—TIMEINTORUN-MINUTESVEHICLEWARM-UPCHARACTERISTICSThevehicleelectroniccomponentdesignerisurgedtodevelopasystematic,analyticmethodfordealingwithsteady-stateandtransientthermalanalysis.Theapplicationofmanydevicescontainingsemiconductorsistemperaturelimited.Forthisreason,thepotentialextremeoperatingconditionsforeachapplicationmustbescrutinizedtoavoidfailureinthefield.4.1.2EFFECTONPERFORMANCE—Thedamagingeffectsofthermalstockandthermalcyclinginclude:4.1.2.1Crackingofprintedcircuitboardorceramicsubstrates.4.1.2.2Thermalstressoffatiguefailuresofsolderjoints.SAEJ1455RevisedAUG94-6-4.1.2.3Delaminationofprintedcircuitboardsandotherinterconnectsystemsubstrates.4.1.2.4Sealfailures,includingthebreathingactionofsomeassemblies,duetotemperature-induceddimensionalvariationthatpermitsintrusionofliquidorvaporbornecontaminants.4.1.2.5Failureofcircuitcomponentsduetodirectmechanicalstresscausedbydifferentialthermalexpansion.4.1.2.6Theaccelerationofchemicalattackoninterconnects,duetotemperaturerise,canresultinprogressivedegradationofcircuitcomponents,printedcircuitboardconductors,andsolderjoints.Inadditiontothesephenomena,hightemperatureextremescancauseamalfunctionby:4.1.2.7Exceedingthedissociationtemperatureofsurroundingpolymerorotherpackagingcomponents.4.1.2.8Carbonizingofthepackagingmaterialsresultingintheeventualprogressivefailureoftheassociatedpassiveoractivecomponents.Thisispossibleincasesofexcessivelyhightemperature.Inaddition,noncatastrophicfailureispossiblebecauseofelectricalleakageintheresultantcarbonpaths.4.1.2.9Changingtheactivedevicecharacteristicswithincreasedheat,includingchangesingain,impedance,collector-baseleakage,peakblockingvoltage,collector-basejunctionsecondbreakdownvoltage,etc.4.1.2.10Changingthepassivedevicecharacteristics,suchaspermanentortemporarydriftinresistorvalueandcapacitordielectricconstants,withincreasedtemperature.4.1.2.11Changingtheinterconnectandrelaycoilperformanceduetotheconductivitytemperaturecoefficientofcopper.4.1.2.12Changingthepropertiesofmagneticmaterialswithincreasingtemperature,includingCuriepointeffectsandlossofpermanentmagnetism.4.1.2.13Changingthedimensionsofpackagesandcomponentsleadingtotheseparationofsubassemblies.4.1.2.14Changingthestrengthofsolderedjointsbecauseofchangesinthemechanicalcharacteristicsofthesolder.4.1.2.15Theseveremechanicalstresscausedbyiceformationinmoisturebearingvoidsorcracks.4.1.2.16Theveryrapidandextremeinternalthermalstresscausedbyapplyingmaximumpowertosemiconductororothercomponentsafterextendedcoldsoakunderaberrantoperatingconditionssuchas36Vbatteryjumperstarts.4.1.3RECOMMENDEDTESTMETHODS4.1.3.1TemperatureCycleTest—RecommendedthermalcycleprofilesareshowninFigures2a,b,andcandrecommendedextremetemperaturesinTables1Aand1B.Iftemperaturecharacterizationhasbeenperformedaccordingto4.1.1.4themeasuredtemperaturemaybesubstitutedforthevaluesinTables1aand1bforthepurposeofthisdocument.ThetestmethodofFigure2a,a24hcycle,offerslongerstabilizationtimeandpermitsaconvenientroomambienttestperiod.Figure2b,an8hcycle,providesmoretemperaturecyclesforagiventestduration.Itisapplicableonlytovehicleelectroniccomponentswhosetemperatureswillreachstabilizationinashortercycletime.Stabilizationshouldbeverifiedbyactualmeasurements;thermocouples,etc.Itisimportantthatallpartsofthetestspecimenbeheldatthespecifiedmaximumandminimumtemperaturesforatleast15min,afterreachingstabilityatthattemperature.Thisistomaintainthermalorpressurestressesgeneratedinthetestspecimenforareasonableperiodoftime.Figure2cillustratesatestmethodforthermalshock.SAEJ1455RevisedAUG94-7-FIGURE2A—24HOURTHERMALCYCLESAEJ1455RevisedAUG94-8-FIGURE2B—SHORT(8HOUR)THERMALCYCLEFIGURE2C—THERMALSHOCKSAEJ1455RevisedAUG94-9-TABLE1A—ENVIRONMENTALEXTREMESUMMARYHEAVY-DUTYCABOVERENGINETRUCK/TRACTORLocation(1)1.Figure3-PictorialDescriptionofLocationsTemperaturesMinTemperaturesOperatingTemperaturesMax(2)2.Iftemperaturecharacterizationhasbeenperformedaccordingto4.1.1.4,themeasuredtemper-aturemaybesubstitutedforthevaluesinTables1aand1bforthepurposeofthisdocument.ENGINE1aUnderhood-Lower-40°C56°Coverambient-40°F100°Foverambient1bUnderhood-Upper(3)3.ExhaustManifold816°C1500°F-40°C222°Coverambient-40°F400°Foverambient1cUnderhoodBulkhead-40°C56°Coverambient-40°F100°FoverambientINTERIOR:2aFloor-40°C27°C66°C-40°F80°F150°F2bInstrumentPanel(4)4.Windshield(Daylightopeningontopofinstrumentpanel)Directsunlightsurfacetemperature115°Cmaximum240°Fmaximum-40°C24°C85°C-40°F75°F185°F2cHeadliner-40°C24°C79°C-40°F75°F175°F2dInsideDoor3aBunkArea-40°C24°C93°C-40°F75°F200°F3bStorageCompartment-40°C24°C74°C-40°F75°F165°FCHASSIS:4aForward-40°C120°C-40°F248°F4bRear-40°C95°C-40°F203°FEXTERIOR:5aUnderNoData5bBackNoData5cDoor-40°C56°Coverambient-40°F100°Foverambient5dTopNoDataMaximumambienttemperaturemayreach85°C(185°F)SAEJ1455RevisedAUG94-10-TABLE1B—ENVIRONMENTALEXTREMESUMMARYHEAVY-DUTYCONVENTIONALENGINETRUCK/TRACTORLocation(1)1.Figure3-PictorialDescriptionofLocationsTemperaturesMinTemperaturesOperatingTemperaturesMax(2)2.Iftemperaturecharacterizationhasbeenperformedaccordingto4.1.1.4,themeasuredtemper-aturemaybesubstitutedforthevaluesinTables1aand1bforthepurposeofthisdocument.ENGINE1aUnderhood-Lower-40°C56°Coverambient-40°F100°Foverambient1bUnderhood-Upper(3)3.ExhaustManifold816°C1500°F-40°C222°Coverambient-40°F400°Foverambient1cUnderhoodBulkhead-40°C56°Coverambient-40°F100°FoverambientINTERIOR:2aFloor-40°C27°C75°C-40°F80°F165°F2bInstrumentPanel(4)4.Windshield(Daylightopeningontopofinstrumentpanel)Directsunlightsurfacetemperature115°Cmaximum240°Fmaximum-40°C24°C85°C-40°F75°F185°F2cHeadliner-40°C24°C79°C-40°F75°F175°F2dInsideDoor3aBunkArea-40°C24°C93°C-40°F75°F200°F3bStorageCompartment-40°C24°C74°C-40°F75°F165°FCHASSIS:4aForward-40°C121°C-40°F250°F4bRear-40°C93°C-40°F200°FEXTERIOR:5aUnderNoData5bBackNoData5cDoor-40°C56°Coverambient-40°F100°Foverambient5dTopNoDataMaximumambienttemperaturemayreach85°C(185°F)SAEJ1455RevisedAUG94-11-FIGURE3—VEHICLEENVIRONMENTALZONESSAEJ1455RevisedAUG94-12-Separateorsingletestchambersmaybeusedtogeneratethetemperatureenvironmentdescribedbythethermalcycles.Bymeansofcirculation,theairtemperatureshouldbeheldtowithin±3°C(±5°F)ateachoftheextremetemperatures.Thetestspecimensshouldbeplacedinaposition,withrespecttotheairstream,wherethereissubstantiallynoobstructiontotheflowofairacrossthespecimen.Iftwotestspecimensareused,caremustbeexercisedtoassurethatthetestsamplesarenotsubjecttotemperaturetransitionratesgreaterthanthatdefinedinFigures2aand2b.Directheatconductionfromthetemperaturechamberheatingelementtothespecimenshouldbeminimized.NOTE—Airflowisafunctionofactualequipmentlocation.Simulationofactualairflowandthermaltransferoperationconditionsshouldbeconsideredintestdesign.Electricalperformanceshouldbemeasuredundertheexpectedoperationalminimumandmaximumextremesofexcitation,inputandoutputvoltage,andloadatboththecoldandhottemperatureextremes.Thesemeasurementsprovideinsightintoelectricalvariationswithtemperature.4.1.3.2ThermalShockTest—ThermalshockthatcanbeexpectedinthevehicleenvironmentissimulatedbythemaximumratesofchangeshownontherecommendedthermalcycleprofileportrayedinFigure2c.Thethermalshocktestshouldbeginwitha2hpresoak(-40°C/-40°F).Thetestitemshouldbetransferredtothehotchamber(85°C/185°F)whereitshouldremainfor2h,thentransferredtothecoldchamber(-40°C/-40°F)for2h.Thiscycleshouldberepeatedatleastfivetimes.Eachtransfershouldbeaccomplishedin1minorless.4.1.3.3ThermalStress—ThermalstressiscausedbyrepeatcyclingthroughthethermalprofilesofFigures2a,b,andc.Manyfailuresareduetofatigue.Slowcyclesnotrepeatedoftenwillnotdemonstratethis.Thenumberofcyclesisafunctionofthevehicleelectroniccomponentapplication.Functionalelectricaltestingduringtemperaturetransitionsorimmediatelyaftertemperaturetransitions,isameansofdetectingpoorelectricalconnections.Theeffectofthermalstressissimilartothermalshockbutiscausedbyfatigue.NOTE—Althoughuniformoventemperaturesaredesirable,theonlymeansofheatremovalinsomevehicleenvironmentsmaybebyspecialheatsinksorbyfreeconvectiontosurroundingair.Itmaybenecessarytouseconductiveheatsinkswithindependenttemperaturecontrolsintheformercaseandbafflesorslowspeedairstirringdevicesinthelattertosimulatesuchconditionsinthelaboratory(seeSection3).4.1.4RELATEDSPECIFICATIONS—AgenerallyacceptedmethodforsmallparttestingisdefinedinMIL-STD-202F,Method107F,ThermalShock,MethodAorB,alternatelyMIL-STD-810D,Method503.2.Theshortdwellperiodsathightemperaturearesatisfactorywheretemperaturestabilizationisverifiedbyactualmeasurements.4.2Humidity4.2.1DEFINITIONS—(Containedin4.2.2)4.2.2EFFECTSONPERFORMANCE—Bothprimaryandsecondaryhumiditysourcesexistinthevehicle.Inadditiontotheprimarysourceexternallyappliedambienthumidity,thecyclicthermal-mechanicalstressescausedbyoperationalheatsourcesintroduceavariablevaporpressureontheseals.Temperaturegradientssetupbythesecyclescancausethedewpointtotravelfromlocationsinsidetheequipmenttotheoutsideandback,resultinginadditionalstressontheseals.Theactualrelativehumidityinthevehicledependsonfactorssuchasoperationalheatsources,trappedvapors,air-conditioning,andcool-downeffects.Recordeddataindicatesanextremeconditionof98%relativehumidityat38°C(100°F).SAEJ1455RevisedAUG94-13-Primaryfailuremodesincludecorrosionofmetalpartsbecauseofgalvanicandelectrolyticaction,aswellascorrosioncausedbyinteractionwithcontaminatedwaterandoxygen.Otherfailuremodesincludechangesinelectricalproperties,surfacebridgingcorrosionproductsandcondensationbetweencircuits,decompositionoforganicmatterbecauseofattackingorganisms(forexample,mildew),andswellingofelastomers.4.2.3RECOMMENDEDTESTMETHODS—Themostcommonwaytodeterminetheeffectofhumidityonvehicleelectroniccomponentsistoovertestandexamineanyfailureforrelevancetothemoremoderateactualoperatingconditions.Themostcommontestisan8hactivetemperaturehumiditycyclingunderacceleratedconditions(Figure4a).Asecondtestisan8to24hexposureat103.4kPagagepressure(15lbf/in2gage)inapressurevessel(Figure4b).Thisisaquickandeffectivemethodforuncoveringdefectsinplasticencapsulatedsemiconductors.FIGURE4—RECOMMENDEDHUMIDITYCYCLESSAEJ1455RevisedAUG94-14-Anoptionalfrostconditionmaybeincorporatedduringoneofthesehumiditycycles.Electricalperformanceshouldbecontinuouslymonitoredduringthesefrostcyclestonoteerraticoperation.Heat-producingandmovingpartsmayrequirealteringthefrostconditionportionsofthecycletoallowaperiodofnonoperationinducedfrosting.4.2.4RELATEDSPECIFICATIONS—Manyrelatedhumidityspecificationsarerecommendedforreviewandreference.Thefirst:MIL-STD-810D,Method507.2,ProceduresIthroughIII,Humidity,isasystem-orientedtestmethod.Thesecond,amodifiedversionofMIL-STD-202F,Method103B,Humidity(SteadyState),isintendedtoevaluatematerials.Thethird,MIL-STD-202F,Method106E,MoistureResistance,isaprocedurefortestingsmallparts.4.3SaltSprayAtmosphere4.3.1DEFINITION—(Containedin4.3.2)4.3.2EFFECTONPERFORMANCE—Vehicleelectroniccomponentsmountedonthechassis,exterior,andunderhoodareoftenexposedtoasaltsprayenviro