ML17321A100

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Dry Film Coating Thicknesses of Thermo-Lag 330-1 Subliming Matl Applied to Steel Hatch Covers for 3 H Fire Rating.
ML17321A100
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Issue date: 02/15/1984
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WESSON & ASSOCIATES, INC.
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DRYFILMCOATINGTHICKNESSESOFTHERMO-LAG330-1SUBLIMINGMATERIALAPPLIEDTOSTEELHATCHCOVERSFORTHREEHOURFIRERATINGPreparedbyWessonandAssociates,Inc.P.0.Box1082Norman,Oklahoma730702iPDRADQCK05000315PDRWESSONANDASSOCIATES,INC.February15,1984

DRYFILMCOATINGTHICKNESSESOFTHERMO-LAG330-1SUBLIMINGMATERIALAPPLIEDTOSTEELHATCHCOVERSFORTHREEHOURFIRERATINGI..INTRODUCTIONThepurposeofthisreportistopresentthecalculatedminimumdryfilmcoatingthicknessesof,THERMO-LAG330-1SublimingMaterialappliedtosteelhatchcoverswhichareprovidedinthefloorsofnuclearpowerfacilities.Thesehatchcoversareusedtosealtheconnectingpassagewaysbetweentwofloorlevelsorbetweenafloorandavaultbeneaththefloorinthesenuclearfacilities.TheminimumdryfilmcoatingthicknesseshavebeencalculatedtoprovideathreehourfireratingwhensubjectedtothefireconditionspecifiedbyASTME-ll9TestMethod.Inthistestprocedure,thetime-averagedincidentheatfluxforathree-hourexposureis42,000Btuperhourpersquarefoot.ThebasisforthedeterminationoftheminimumdryfilmcoatingthicknessesfortheTHERMO-LAG330-1SublimingMaterialappliedtoflatplatesisanengineeringcorrelationdevelopedfromexperimentalresultsfromfiretestsconductedonthematerial.Theexperimentaldatausedinthecorrelationincludetheresultsoffiretestscon-ductedby'everalindependentorganizationssuchastheUnderwriter'sLaboratory',theU.S.'epartmentofTransportation(FederalRailrbadAdministration),MobilOilCorporationandWessonandAssociates,Inc.Theminimumdryfilmcoatingthicknesseshavebeencalculatedforhatchcovershavingthicknessesof3/16,3/8and1/2inches,fireex-posurefromonesideonlyandsimultaneousfireexposureonbothsides0ofthehatchcover.Thetemperaturerisesusedincluded250FforLESSONANDASSOCIATES,INC.

0personnelconsiderationsand930Fformaintainingthestructuralintegrityofthesteel.II.ENGINEERINGCORRELATIONFORFLATSTEELPLATESThethermalperformancecharacteristicsoffireproofingmaterialssuchasTHERMO-LAG330-1SublimingMaterial,THERMO-LAG290SublimingMaterial,CHARTEK59,KOROTHERMandPYROCRETE102havebeenfoundtocorrelateas:wheret=afunctionof(T,QT,W,F)t=fireexposuretime,minutesT=dryfilmcoatingthicknessoffireproofingmaterial,'inches0QT=temperatureriseoftheprotectedmetalsubstrate,FW=effectiveheatcapacityofprotectedmetalsubstrate,poundspersquarefootofexposedareaF=totalincidentheatflux,thousandsofBtuperhourpersquarefoot.Experimentalfiretestdataexpressingthefireexposuretimeasafunctionofthefireproofingmaterialcoatingthickness,thetemperatureriseoftheprotectedmetalsubstrate,theweightoftheprotectedmetalsubstrate'ndthetotalincidentheatfluxhavebeenusedtodeveloprempiricalengineeringcorrelationsfortheTHERMO-LAG330-1SublimingMaterialappliedtovarioussubstratessuchasflatsteelplates,pipesandstructuralsteelmembers(I-beams).Therangeoftotalincidentheatfluxeshavevariedfromalowof10,000Btuperhourpersquarefoottoahighofabout95,000Btuperhourpersquarefoot.Thecoatingthicknesseshavevariedfromalowof0.125inchestoahighofabout1.25inches.Theengineeringcorrelationexpressingtheexposuretimeofaprotectedsteelplateasafunctionofthecoatingthickness,temperatureriseofthemetalsubstrate,theeffectiveheatcapacityoftheprotectedsub-strateandthetotalincidentheatfluxisWESSONANDASSOCIATES,INC.

1.3356t=23.002(T)(QT)(W)/(F)(2)whereWiFexpressedinpoundspersquarefootofprotectedflatplateexposedtbtheincidentheatflux.TheengineeringcorrelationispresentedinFigurel.Asnotedonthisfigure,iftheprotectedsub-strateisexposedtoafireconditiononbothsides,theeffectiveheatcapacity,W,isbasedonone-halfthethicknessoftheplate.4III.INCIDENTHEATFLUXESFROMFIRESTheincidentheatfluxesfromtheASTME-119TestMethodandfromflammableliquidspillfiresarewidelyusedforthedeterminationoftherequiredfireproofingcoatingthicknessesforvariousprotectedsteelsubstrates.ASTME-119TestMethod:TheASTME-119TestMethodusesaspecifictime-temperaturerelation-sshipfortestingthefireresistive.capabilitiesofvariousfireproofingmaterials.Therequiredtime-temperaturerelationshipispresentedinFigure2.Asshowntheinternalairtemperatureofthethetestset-upstartsattheprevailingambientairtemperature,reachesatemperature0of1700Fattheendofthefirsthourofexposure,atemperatureof1850Fattheendofthesecondhourofexposureandatemperatureof0ofabout1950Fattheendofthethirdhourofexposure.Thisspeci-0fiedtime-temperatureprofiledoesnotrepresentthetime-temperatureprofileforatypicalhydrocarbonspillfirewhereinthetemperature0withintheflamezonemayreachatemperatureofabout2200Formorewithinaveryshortperiodoftime(onetothreeminutes).Thus,theASTME-119TestMethoddoesnottrulyrepresenttheenvironmentofaflammablehydrocarbonfire..Thetime-heatfluxrelationshipcorrespondingtothetime-temperatureprofilespecifiedbytheASTME-119TestMethodispresentedinFigure3.Asindicatedonthisfigure,theintegratedtime-averagedincidentheatfluxesare24,500Btuperhourpersquarefootforthefirsthourofexposure,34,500BtuperhourpersquarefootfortwohoursofexposureWESSONANDASSOCIATES,INC.

4VFIGURE1:CORRELATIONOFTHETHERtRLPERFORMANCECHARACTERISTICSOFTHERMO-LAG330-1SUBLIMINGMATERIALAPPLIEDTOSTEELPLATESANDPIPESNOTE:Foranglesorplateexposedonbothsides,useW~@eightofmetalsub-strate,lbs/sq.ftofexposedareabasedonone-halflegorplatethickness200~Testpointsfor300Fmetalsubstrate00~Testpointsfor500Fmetalsubstrate0Testpointsfor800Fmetalsubstrate100II'I~IIII~~~~~III~'~IsIo10~~~IE~~~~III~C'I'O'II'>>23o002(T)(QT)(W)/(F)T~THERMO-LAG330-1Coatingthickness,inchesDT~TemperatureRiseofMetalSubstrate,F0FsWeightofMetalSubstrate,lbs/sq.ftofexposedsurfaceTotalIncidentHeatFlux,thousandsofBtu/hr-sq.ft0.110(T)(DT)(W)/(F)10WZSSONANDASSOCXATESINC.4 FIGURE2:ASTME-119TESTMETHODTIME-TEMPERATUREPROFILE(st029002400~~~~~....s....I~~~~~II~!:>>I~'.Ils.".>>IIee.'~IIII',Ie.(.-i)ii'!I!!.'I.'ll:,'.:I'.."I'.l.lilalI(llj:aj.".~II.>>~IllI~~s~~~eaI)()ij~>>)~Ie~e"I~~~()il)'~"-'I">>I!(':!~so'.sl('.::>>'.:':"I:~.'ll'.I~.~ela"a'I'I~~'ll;":IIII"I:I's-I:ill~Ii'(I(II'"el"'i"-:>>:iI'::I(I"'=.)llI""'..Is):II~."..II..III~lI.~j.~'.ll'llsI'eIIjIIjl.':::IeI(jllI~aII~II'I'IIIIIi)'llI'i'ijIjII'IIIj1600'::..'."'ii'I'I!IiI<'"'I'>>.'III:III!III!i!i!ilj)III~IIel)~jIjijIIij~~I~aI~I~eI.)j~"Ii','Ij~I'Ijjj'Ilj~II,','i()!I)lle):I>>II':IIiI~~~~Ii)iI:I:..III:i':llill1200"'I:.'i.I!II":I!i'I~Ijji.j'(elI~::::.;.:il!I:iljiI>>I:I'il(I'.I'I'I'III'jsill(I'"'"'i'II">>~":>>I."","II:s'I'llill~~>>"(II~.I.~.>>...e...l.I...ee~...Is.~Is).."...~...I....Ill...)'(e...ll.~..II.III'III!III'!ilI~()III)IIIIII~III())Ij,IIIII'~~(II(~I~II,;IIIIII~IIse'I~el~e(~i!iI.'!Ii"!I!Iil!',iI!ijii!(jji'!!jiii'!!!IIll~I'lli'llIa'I'I'sII)'>>I:"(>>I'.::~(<<III'aI:IIII(IIlljl;(j::i"Il~I'"""~~8pp~.e~III...~I~IaIIIIiI'I.....(I)s(ai.I.~Ii).~..e~I~II~IeIIIIjI~III!!::III'I.:>>'~'II'IIllsI~,:>>:.'ll!)a()()I.'llIII'IIjilIi)jI"I'I'I""I'IliIIIIIIIII(.IIll.)II..~I~IllI(()IiIIll(,'IjI'j'ilj'(j:~.,'II'a'll":'jIl!ijl>>!~.I!'II'I.I'll!i!i'jijI>>iWill,i~~I~I~lljlI)I~II~siel~j~~I~ijill)ij"i'li,'ii'~~~IjlI,Ie~'isei<<IIIeI's,'alle)I~Ij'III)IIII:;e>>~IIIji~IIIiIjl)Ij~j>>I'IIII.I)ll~II~Ies>>I~III)I)..)ei~.~.....,(IIi.,e'~j~~~Is~Ie0~I,,j.IliIIIj~~II)~jIji:'>>Ii)I'.".illiilIII'.!.:!i:!:!!:i:I'>>:Ill"Ii"'!I!!'!,'~I:Ii!:.:IlI'I,j.~,.;(Iij,,i..I..I,>>.,,-,...,'...II.I~I.,Ii,,ij"',,:.:i!,"iI!IIIi:'I'.~',.;Is0345FIREEXPOSURETIME-hours78910 604JIm5040440I3020Mu100FIGURE3(INCIDENTHEATFLUXLEVELOFFIRESPECIFIEDBYASTME-119TESTMETHODASAFUNCTIONOFFIREDURATION/EXPOSURETIMEII'(~:1.4~.ai~~j:II~::ii'i!I.:.~~i;ij!I~:::I44I~~~~~~I:iliIfjii:Ie4~~~~ilII':~IIII~!~4~Ii'i.'iilII:i'h(i"~:I~~~~~<<~~I~~I~4+aIaa4;I;::*;I:.I~~~I~aI.'~I:III'I~.II'I~IjIi::!ll'I(js!!.Ij.~::i::~~::I:il!!.!!ilIj'I~I~-I:~~-~~all.~..~~~~ijl~j!Iljl'~'~~:...II~~~'.~.ll',~~ii!:il:.j.'I'.~I::a!.Is.ill:III~J!".~~Ii.iiii'.~~~Ii:jI!I"!'.:l:IIIIsII~'..I~i'lI;IIis'Iail:.II:I::iiI~:I:,!Jl~III!:I:a~~Iajl;~(Ii!IijI~~~~~~~I~4lJ'Iua:isi'I!I!!.~ilsI:p~~:'I~~II"~I~I~i:I'((II~IItt:I.'I~i:~~I'I.'.:~II~I~~~ae~~~~~'.I:III!i!:l'j!e~IIel>>(II~I~.'(II~I(lili:I!"~.'illI~jLJ:i:JI~~I'I:Jig!ll.il!(I~i(:.I~~~~~~I~IIII:I"JjLJ:::.II:.:'I~~i(j:il;":il:i!':!:I:!ilij~~~I~~~~~~~-~';tijl.~III~II(J)II:jj:lill:IIij::il'::(I;fj(!:!4~!.I~I~~IIi!jjj!;IlIll(~~I'll~~~I~~~~~~~~~"ililailil::~I~I~~~I"!I~IJI!'I~il~<<ia(J,lieJ!!i!I~I"!IIl~~I~JaI:II~TIME-AVERAGEDINCIDENTHEATFLUXES'!l:~~~~ONE-HOUREXPOSURE:24,500Btu/hr-ft2TWO-HOUREXPOSURE:34,500Btu/hr-ft2THREE-HOUR'EXPOSURE:42,000Btu/hr-ft2I!@ji(:J.i~I::~sl!I:'.:.'I:~.,Iia!::I:~li~Li~~ii.!;!I.:.JslII~III~I~~Ji,!II!,I~Jill'!IJ!:i(Lli;Iils(iiii!!l:II::".'I)J;jj;~';JI~uilliIIIle~III'I:~Isij(il':.:III!j:~I'l"JIi'IIll.!!:j~I~Ilil!!il!III'll'l',!!I!~~~III'Ii.lI~S~~::IIlj!"!i.jI:la!I('ll~~:.l'j!jan!)IJjJiIjl'~~~~ls::I:IJlI~~I~!::.!I!sjl:i'~~~II;I~~~~I~060120180TIME-minutes and42,000Btuperhourpersquarefootforthreehoursofexposure.HdrocarbonPoolFireTotalHeatFluxes:Itmustbeemphasizedthatallliquidhydrocarbonfiresdonotproducethesametotalheateffects.AsshownbyTable1,differentliquidhydrocarbonflameshaveverydifferentheatingeffects.Forexample,afireinvolvingmethanolwillonlyproduceatotalincidentheatfluxofabout12,000Btuperhourpersquare.footwhereasafireinvolvingLPGcouldproduceatotalheatfluxofabout40,000Btuperhourpersquarefootforarelativelylargediameterspillfire(firediametersinexcessof30feet).Sincethetotalincidentheat,fluxappearsasalinearterminEquation(2),itisveryimportanttospecifyorknowthetypeoffireforthedeterminationoftherequiredfireproofingcoatingthickness.IncidentHeatFluxUsedinDeterminationofCoatinThicknesses:Thethreehourfireratingpresentedhereinhasbeenbasedontheincidentheatfluxlevelassociatedwithathree-hourexposuretothefirespecifiedinASTME-119TestMethod.Thetotalincidentheatfluxusedtocalculatethecoatingthicknesseswas42,000Btuperhourpersquarefoot.IV.REUIREDTHICKNESSESFORSTEELHATCHCOVERSAcompletelistingofthecalculatedcoatingthicknessesofTHERMO-LAG330-1SublimingMaterialappliedtosteelhatchcoversispresentedinTable2.Fourcasesarepresentedtocovervariousaspectsoffireexposureandtemperaturerisesofthesteelhatchcovers.Thecoversareassumedtobeexposedtoafirefromonesideonlyandalsotoafirefrombothsidessimultaneously..Thetemperaturerisesconsidered00were250Finconsiderationofpersonnelsafety'and930Finconsidera-tionofstructuralintegrityofthecovers.ItshouldbepointedoutthatthedryfilmcoatingthicknessespresentedinTable2donotincludea10percentagingandweatheringallowanceWESSONANDASSOCIATES,INC.

TABLE1TYPEOFFUELMAXIMUMHEATTRANSFERFROMFLAMESTOCOLDTARGETRADIANT(BTU/HR-FT.SQ.)CONVECTIVETOTALMethanolAcetoneHexaneCyclohexaneJP-4:SmallSpillFireJP-4:LargeSpillFireBenzolLPG:SmallSpillFireLPG:LargeSpillFireLPG:ImpingingFireLNG:SpillFireonLandLNG:SpillFireonWaterEthylMercaptanT"ButylMercaptanEthyleneButhyleneButadieneCarbonMonoxideVinylChloride5,00010,00022,50031,00023,70031,00039$00025,50034,50045,000(Maximum)45,000(Maximum)18,80023,50028$50029,7502705004,5008,5007,0007,0007,0007,0007,000'0,0007,0007,00010,00010,00010,0007,0007,0007>0007,0007,0007,0007,00012,00017,00029,50038,00030,70041,00046,00032$50045,50070,00055,00055,00025,80030,50035,50036,75034,50011,50015,500AVESSONANDASSOCIATES,INC.

and,therefore,representtheabsoluteminimumrequiredcoatingthick-nesstoprovidethespecifedfirerating.ThisallowanceisbasedonlongtermenvironmentaltestingprogramsconductedbyUnderwriters'aboratories,U.S.AnnyBallisticsResearchLaboratoriesandcommercialusersinthehydrocarbonprocessingindustry.Therefore,toprovideanallowanceforagingandweatheringoftheTHERMO-LAG330-1SublimingMaterial,thecoatingthicknessespresentedhereinshouldbeincreasedbyatleast10percent.WESSONANDASSOCIATES,INC.

TABLE2MINIMUMDRYFILMTHICKNESSESFORTHERMO-LAG330-1SUBLIMINGMATERIALAPPLIEDTOSTEELHATCHCOVERSBasisforFireRatin:Three-hourexposuretofireconditionspecifiedbyASTME-119TestMethod2HeatFlux=42,000Btu/hr-ftHatchCoverThicknessinchesExposure*ConditionDryFilmCoatingThicknessinInches**250FDT930F~T0.18750.3750.500singlesinglesingle1.4951.0550.9150.5950.4200.3650.18750.3750.500doubledoubledouble1.4951.2950.5950.5152.1100.840*Denotesfirefromoneside(single)orfirefrombothsides(double).**Doesnotincludeanyallowanceforagingandweatheringofmaterial.WESSONANDASSOCIATES,INC.10 4~g~~~Sub...ittedtoButane-PropaneNews:April1976THERt'MEFFECTIVENESSOFVARIOUSFIRERESISTANTCOATINGSAPPLIEDTOSTRUCTURALST"ELSEXPOSEDTODIRECTFLAYERSCONTACTAND/ORRADIATIVEHEATFLUXESH.R.WessonWesson6Associates,inc.P.0.Box1082Norman,OK73069INTRODUCTIONTherapidlygrowingacceptanceoffireresistantcoatingsforthermalprotectionofstructuralssteels,flammableproductstoragetanks,pressurevesselsupportstructure,amongotherapplications,hasplacedthisuniquefireproofingconceptinanapprovedposi-tionforextensiveusageintheareaof"exposurecontrol"forstructuresthatcouldbeexposedtodirectflamesimpingement,freeburningpluspressuretorchingconditions,and/orprolongedperiodsofhighintensityradiativeheatfluxes.Theinherentreliabilityandlowmaintenancecostsforthis"passiveconcept"ofexposureprotection,togetherwiththelowperformancelevelofconventionalwatercoolingsystemsunderflameengulfmentand/orhighpressureimpingingortorchingtypefireconditions-,havealsogiv..thesefireproofingcoatingsaveryhighcost-effective,orcost-benefit,characteristicforhighheatintensityapplications.Thesetypecoatingsarealsofindingapplicationswheresimultaneouslowtemperature(cryogenicliquidimpingingconditions)andhightemperature(flamescontactconditions)protectionisrequiredforthestructuralsteelsinLPG,LNG,andSNGfacilities.Thedifferenttypesoffireproofingcoatingsthatarecommonlyavailable,theresultsof.extensivefiretestingonthesecoatings,andengineeringcorrelationsoftheexperimentaldatathatcanbeusedfordeterminationoftherequiredcoatingthicknessesforadesiredperiodofprotectioninvariousheatingenviron-.mentsarepresentedanddiscussedherein.GENERALTYPESOFFIREPROOFINGCOATINGS=Themostc'ommonlyacceptedfireproofingcoatingmaterialsincludethefollowing:WESSONANDASSOCIATES,INC.

~~~~~I2.CementCompounds:Concrete,gunite,andsimilarconcrete'asecompoundsprovidegoodfireexposureprotectionduringbothdirectflamescontactandhighintensityflamesradia-tioncond':ionsforextendedperiodsoftime.Ingeneral,however,thecementcompoundsarequiteheavy,areexpensivetoinstall,insomeapplicationsarecorrosive,andingeneralexhibitpoormechanicalbondingpropertiesbetweenthesub-strateandthecementcompound.AblativeCoatings:Thesetypecoatingsprovideexcellentfireexposureprotectionforstructural.steels.Thefunda-mentalprincipleistoapplyacoatingthatgraduallyerodesduetotheabsorbedenergyinputfromafirecondition.Tochangetnevirginsolidcoatingintoagascompositerequiresheatinputthatwouldotherwisebeabsorbedbythestructurebeingprotected.Thetemperatureriseoftheprotectedstruc-tureisretardedindirectproportiontotheablativecoatingthicknessanditsthermalproperties.Theincorporationofceramic-likeintumescents'haveresultedinatoughmicroporouscharlayerwhichprovidesadditionalinsulatingpropertieswhilemostoftheheatinputisrequiredforthephysicaltransformationofthebasematerial.Themajordisadvantagesofthesetypeablativecoatingsappeartobethecomplexityoftheapplicationprocessandthefinalinstalledcoatingcosts.3.SublimingCompounds:Thesublimingcompoundsprovideapro-tectedsubstratetemperaturebasedonthetemperatureofsub-limationforeachparticularcompound,thethicknessofthecoatingmaterial,theheatcapacityofthesubstrate,thecoatingthermalproperties,andthedegreeandtimeofheatexposure.Ingeneral,-thesublimingcompoundsformaverytough,estheticcompoundthatisverytightlybonded(bondingstrengthof100psiandmore)totheprotectedsteelsurface.AnotherprimeadvantageofthesublimingcompoundsisthattheyarenotadverselyaffectedbyprolongedexposuretolowtemperatureliquidssuchasLNGandLPG,aswellassimultan-eousexposuretosuchlowtemperatureflammableliquidsandresultantflamescontactheatingeffectsfromliquidspillfires.TheseadvantageousthermalpropertieshaveresultedintheuseofthesublimingcompoundsatsomeLNGFacilitiesfortheprotectionofcarbonsteelstructures,includingtheactualLNGstoragetank,.thatcouldbesubjecttoLNGsub-mergenceand/orLNGliquidsprayimpingementaswellasdirectLNGspillfireflamescontact.Thesecoatingsmustbeappliedtospecifiedtypesofprimepaintedmetalsurfaceswithairlesssprayequipmentduringrelativelywarmanddryatmosphericconditions(above40Fandnotduringrains).LESSONANDASSOCIhTES,INC.

4.DepartmentofTransportationagingandenvironmentaltestsgivethesetypecoatingsa20-yearlifewhenproperlycuredandthetop-coatrenewedeveryfivetosevenyears.InturnescentMasticCompositions:Themostcommonofthesetypecoatingsareamodifiedvinyl,heavy-bodiedmasticcontaininginorganicfibersinanaromaticsolventblendandareinforcedepoxy,twocomponent,100percentsolids(nosolvent)spraysystem.Ingeneral,thesetypecoatingsreactbyabsorbingheatinachemicalreactionwhichgeneratesafoam-charsystemontheflamesexposedsideofthecoating.Additionalheatinputisusedtodrivetheliberatedgasesthroughthematrix.Thefoam-charisalsoaneffectivethermalinsulator.Alloftheseheatabsorbingand/orheatflowretardingmechanismsservetokeepthesubstratebelowitsallowableratedmaximumoperatingtemperature.Theperiodofsubstrateprotectiondependsonthecoating.thickness,theapplicablethermalpropertes,andtheperiodandintensityofheatexposure.Theheatcapacityoftheprotectedsub-stratealsosignificantlyaffectstheperiodofprotectionforagivencoatingthickness.Likethesublimingcompounds,thesemasticsdonotsufferanyadverseconsequenceswhensubjectedtoLPGandLNGcontact,andarebeingusedforthermalprotectionofsteelstructuresassociatedwithLNGstoragetanks.Onedisadvantageofthesetypecoatingsappearstobethegreaterthickness.requiredforthesameperiodofprotectionxnagivenfiresituation.Forexample,thepublishedresultsoftestsusingtheASTM-K-119TestMethodindicatethatusinga1000Ftemperaturefora8';iF31beamasabasisforcomparison,aQ"thickcoatingofatypicalvinyl-basetypeintumescentmasticwillgivea"two-hour"firerating,.a5/8"thickcoatingoftheepoxy-basedintumescentmasticwillprovidea"two-hour"firerating,andaQ"thicksublimationcompoundcoatingwillgiveafireratingof"twoandone-half"hours.Anotherdisadvantageofsomeoftheintumescentsappearstobethepropensityoft'eactiveingredientstoleachoutoverprolongedperiodsofexposuretooutdoorenvironmentalconditions.Oncesuchaleachinghasoccurred,theprotectiontimeintervalprovidedbysuchcoatingsissignificantlyreducedovertheinitialratingperiod.Asindicatedabove,theheatcapacityoftheprotectedsub-'stratesignificantly'affectstheperi'odofprotectionpiovidedbyagivencoatingthickness.AnexcellentexampleofthiseffectwasgivenbyO'ourke(1)inthe1973AnnualA.'I.Ch.E.symposiumonthefireproofingofstructuralsteels.Foreaseofreference,Figure1presentsthiseffectforwideflangestructuralsteelbeams.WEssoNhNDAssocIhTEs,INc.

,1,)I1/2C~RIC3A4MO'UOMM7/Z63/8>/161/43/161/81/168WF31STRUCTURALBEAM~10WF49r14MF228///REF.:O'ourke,J.F.,"TheUseofXntumescentCoatingsforFireProtectionofStructuralSteel"20.406080100120140160180200TIMEFORPROTECTEDBEAMTOREACH1000F-minutesFIGUREl:EFFECTOFINTUMESCENTMASTICCOATINGTHICKNESSONTHEEXPOSURETIME)ICc"PII11I~

oUnfortunatelytherearealsoanumberofmaterialswhicharefrequentlyKISUSiDasfireproofingsystems.?'.aterialswhicha'emisusedforoutdoor,fullyexposedenvironmentalconditionsinclude:2.3.StandardThermalInsulationSystems:Conventional,socalledstandardinsulationtechniques,suchasmetallic-sheathcoveredcork,glass-wool,oraggregatesystemssuchasvermiculite,perlite,orcalciteprovideexcellentheattransferprotectionfortheflowing/storedmedia.However,suchsystemsarepoorfireproofingmaterials.Eornallythethermalinsulationsystemshaveverypoorbondingpropertiestothebasestructureandareusuallycoveredwithathinmetallic-sheathingforprotectionofthethermalnsulationfromenvironmentaleffects.Underdirectflamecontact,and/orhighintensityradiativeheatfluxes,thesethinmetalliccoveringswillquicklyexperiencelargedeformationswithanattendantlossofthermalprotection.entrappedmoisturebetweenthethermalinsulationandthesteelstruc-turecanprovideacorrosionproblemaswellasgeneratingsufficientsteampressuretoactuallyblowlargesectionsoftheinsulationsystemoffoftheprotectedstructureunderhighheatfluxconditions.RefractoryProtectionSystems:Yostrefractorymaterialsprovideexcellenthightemperaturethermalprotectioninsuchapplicationsaskilms,ovens,andhightemperatureprocesslines.However,thesematerialsareoftenmisappliedasfireproofingsystemsforsteelstructuresthatcouldbe-comeexposedto.flammableliquidspillfires.Hostflammableliquidsreachtheirmaximumburningintensitywithinafewsecondsandimposeveryhighthermalgradientsintheouterregionsoftherefractoryprotectionsystemsinashortexposureperiod.Underlargethermalgradientsandtheresultanthighthermalstresses,mostrefractorymaterialswillcrackand/orspill,possiblyleavinglargestructuralsectionsofthebasicstructurecompletelyunprotected.Ingeneral,therefractorymaterialsaredesignedtobebroughtuptotheirnormaloperatingtemperatureoveranextendedtimeinterval,aswellasbeingcooleddownquiteslowly.IntumescentPaintCompounds:Thesepaintingcompounds,whenunsubjectedtoflametemperatures,puff.upto,formanair-filledashwhichactslikeaninsulatormaterial.Unfortun-atelytheirabilitytointumesceislostaftershortperiodsofexposuretooutdoorenvironmentalconditions,usuallylessthantwoyears.AveryseriousprobleminusingtheintumescentpaintingcompoundsforthefireproofingofexposedstructuralsteelsthatcouldbesubjectedtohighvelocityWESSONANDASSOCiATESOINC. flamesimpingementistheextremefragilityoftheair-filledashformedbytheexposureoftheintumesc0ntpainttohightemperatures.ExperimentaldatahaveclearlyshownthatthegasvalocitiesassociatedwithClassIflarmableliquidsunderdirectflamecontactconditionsaresufficienttocompletelydestroy,ordislodge,theinsulatingair-filledashlayers'~>laterofHydrationPlasters:Thesecoatingsaresimplyplastercompositionswhichundergochemicalandphysicalchangeswhenexposedtohightemperaturestoreleaswatervapor.Thetheoryisthatthetemperaturesoftheprotectedstructurewillbelimitedtothetemperatureofhydrationprocessandthatthefireenergyisabsorbedbythehydrationprocessandinthevaporiz'ationofthewatervaporproducedbythevariousreactions.Thematerialsthathavebeentestedandreporteduponintheliteraturehaveexhibitedahighdegreeofhydroscopicityandaverylimitedabilitytowith-standexposuretooutdoorenvironmentalconditionsforevenshortexposureperiods,lessthanoneyear.heinherentpossibilityofcorrosionduetothewatercontentofthesecoatingsisaseriousdrawbacktotheuseofthesematerialsforfireprotectionofsteelstructures.DISCUSSIONOFEXPERIMENTALDATATheprincipalsourcesofexperimentaldataonthefireprotectioncapabilitiesofthevarioustypesoffireproofingmaterials,otherthantheindividualcompanyresearchanddevelop-mentprogramswhich'arenotnormallyavailabletothegeneralpublic,aretechnicalpapersthathavebeenpresentedatengine-eringconferencessuchasthe1973AnnualHeetingoftheA.I.Ch.E.inPhiladelphia,PA(1,2),theFireproofingandSafetySymposiumoftheVestemResearchApplicationCenterofLosAnge1es,CA,in1971(3),independenttestingprogramssuchastheDepartmentofTransportation-FederalRailroadAdministrationLPGtorchingtestsoncoatedplatesandfull-scalefireengulfmenttestson33,000galloncapacityLPGtankcarsfilledwithLPGin1974-75(4),andFactoryHutualResearchtestingreportsmadeavailabletotheauthorbyasublimationcompoundtypecoatingmanufacturer(5,6,7;8).Alloftheseseparatesourcesofexperimentaldata.havebeenutilizedtoformaslarge.a.databaseasispossible'oritechnicalevaluationoft&iethermalperformancecharacter-isticsandcapabilitiesofthevariousfireproofingcoatings.Unfortunately,most,ifnotall,theavailableexperimentaldatahavebeenobtainedunderdirectflamecontactconditionsand/orEVESSONhNDASSOCIATES,INC.

iS~(~e7underrelativelyhighpressureimpinging,ortorching,fireconditions,andassucharenotdirectlyapplicabletothoseconditionswhereinonlyprotectionfrom"radiantheatfluxes"isdisired,or-required.However,duetotheverywidevari-ationofthetypesofhydrocarbonfuelsinthevariousdirectflamecontacttests,andtheresultant.widevariationincoatingsurfaceincidentheatfluxes(fromalowof12,000BTU/HRSQ-FTtoahighof67,200BTU/HRSQ-FT),ithasbeenpossibletocorrelatetheexperimentaldatainaformthatitcanbeusedforthepredictionoftherequiredcoatingthicknessforvarioustypesoffireconditionsrangingfromhighpressureflamesimpingementtoonlyincidentradiativeheatfluxconsiderations.TableIpresentsalistingofthedifferenttypesofhydro-carbonfuelsthathavebeenusedinthevariousreportedtestingprogramsandtheradiative,convective,andtotalheattransferratesreportedintheresearchliteratureforeachtypeoffuel.AlistingoftheliteraturesourcesfortheseheattransferratesisalsonotedonTableI.AslistedinTableI,theradiativeheatfluxesrangefor5,000to39,000BTU/HRSQ-FTdependingonthefuelandfiresize,andtheconvectiveheat'fluxesrangefromabout7,000to11,000BTU/HRSQ-FT,dependingonthe.firesize.Atabulationoftheexperimentaldatausedintheengine-eringanalysesandevaluationsreportedhereinispresentedinTableII.Asshown,experimentaldataforasublimationcompoundcoating,anintumescentmasticcoating,acompositesystemcom-posedofaninsulatingtypeconcretewithanexteriorcoatingofanintumescentmastic,andanablativetypecoatinghave'beenutilizedastypicalexamplesofthevariousfireproofingcoatingsapplicablefortheprotectionofoutdoorstructuralsteelsandLPGstoragetanks.ThefuelsusedintheTableIIexperimentalresultsincludemethanol,hexane,JP-4andLPG.Thevariouscoatingthicknessesrangedfrom0.125inchesto0.750inches.Thestructuralsteelsubstratesinclude5/8inchplate(LPGstoragetankshellmaterial)and8$~r31,8VF39and104%49steelbeams.Theexposuretimesfortheparticularsteelsubstretestoreach300oF,500F,800Fand/or1000F,asapplicable,arealsogiven.ThesourcesoftheexperimentaldataarealsolistedonTableII.DATAANALYSES:STRUCTURALSTEELBEAMSInordertogeneralizetheavailabledirectflamescontactandimpingingfiretestdataanddevelopageneralizedengineeringdatacorrelationthatcanbeus'edforanytypeoffireheatingcondition,theTableIIexperimentaldatahavetobeexpressedasLESSONhNDASSOCIhTES,?NC.

~~ft~~-8-.TABLEITOTALRADIANTSUMMARYOFTOTALCONTACTHEATFLUXESFORVARIOUSTYPEHYDROCARBONFLAMESMAXIMUMHEATTRANSFERTOACOLDTARGET(BTU/HRSQ-FT)CONVECTIVEMethanolAcetoneHexaneCyclohexaneJP-4:SmallFiresJP-4:LargeFiresBenzolLPG:ImpingingTypeFiresLPG:Smallspills5,00010,00022,50031,00023,70031,00039,00025,5007,0007,0007,0007,0007,00010,0007,0007,00012,00017,00029,50038,00030,70041,00046,00064,850Avg32,500

REFERENCES:

2.3.4.5.6.Atallah,S.andAllen,D.S.,"SafeSeparationDistancesfromLiquidFuelFires",FireTechnolo,1,47(1971).Law,M.,"StructuralFireProtectionintheProcessIndustry",Buildin,86-90(18July1969).Nei,D.T.,Welker,J.M.,andSliepcevich,C.M.,"DirectContactHeatTransferfromBuoyantDiffusionFlames",J.Fire6Flammabilit1,289(1970).Rasbash,D.J.,Rogowski,Z.E.,andStark,G.W.V.,"PropertiesofFiresandLiquids",Fuel,35,(1956).Bader,B.E.,"HeatTransferinLiquidHydrocarbonFuelFires",Proceedings,InternationalSymposiumforPackagingandTrans-portationof.RadioactiveMaterials,SandiaCorporationandU.S.AtomicEnergyCommission,SC-RR-65-98,Albuquerque,NM(12-15January1965).Anderson,C.,Townsend,W.,Markland,R.,andZook,J.,"ComparisonofVariousThermalSystemsfortheProtectionofRailCarsTestedattheFRA/BRLTorchingFacility",BRLInterimMemorandumReportNo.459(December1975),FundedunderFederalRailroadAdministration,DCNAR30026/Req.731231WESSONhNDASSOCEhTES,INC.

TAbLEIISUMMARYOfEXPERIMENTALDATAONTHERMALPROTECTIONSYSTEMEXPOSEDTODIRECTFLAMESCONTACTTYPEOffUELTYPEOFIOFCOATING.~INCIDENTHEAT'."INCHESOFCOATINGSUBSTRATETHICKNESSFLUX"PKRTHOUDANDSOl'in)(BTU/HRSQFT)BTU/HRSQ-FTTIMEFOlLSUBSTRATETOREACHSPECIPIEDTE%'ERATUREMinutes300of500F800f1~000SUBLIMITATIONCOMPOUNDuII~InuII>II>0>IMethanolHexanellexaneHexaneMethanolllexaneHexaneLYGPress.LPCPresa~LPCPress,JP4JP4:~BWF39Beam'.~eBMF39BeamBWF39Beam1OMF49Beam10MF49BeamIOWF49Beam10MF49Scam5/8"Plate5/8"Plate5/8"Plate5/8"Plate5/8"Plate0,1500;1500.2500.1500,l500.217~0,2000.1250~1870.2500.1250.25012,00029,50029,50029>50012,00029,50029,50064,85064>850'4,65032>50032>5000'1250~00510.00850'051001250.00740,00680.00l930'0290'0380.00380'0777>5142217.449,214.525.5244838>S643360706141>2481513>53448105'17'128120QtTUMESCKNT.MA$TICICIIunl>I>COMPOSITESYSTEM".CON+ADCRETE+1/8"INTUMKSCENT?QSTICTQPCOATINGllexaneHexanellcxaneHexaneHexaneHexanellexaneHexaneHexaneBWF318MF318'WF31IOMF4910WF4910WF498WF31BMF318MF31BeamBeamSeamBeamBoomBeamBeamBeamBoom0.1250.2500.5000.125,0.2500.5000,2500~5000>75030>700'.30,700~30,700'0,700:30,70030,70030,70030,70030,7000.00410~00810.01620'0410.00810,01620'081O,ol620,024435641204573~1325085125i+IATIVKCOATING;,">ILPGPoolPire5/8"PlateL'PGPoolPire5/8"Plate0~125Oe25032,50032>5000.00385~0.0076012194227419SRFERENCES!liAnderson,C.,Tovnsend>W.,Markland>R.,andKook>J"ComparisonofVariousThermalSystemsfortheProtectionofRailCarsTested~ttheFRA/BRLTorchingFacility",BRLInterimMemorandumRcportNo.4S9(Decembet1975)~FundedUndettheFederalRailroadAdmin~istration,DCNAR30026/Rcq.7312312~ConcerningFireProtectiveCoatings,ASvmssryof~SymposiumPresentedattheA.I.Ch.E.MeetinginPhiladelphia,PA(November1973)~3~Fcldmsn>R.,"FireRetardsncyandHeatTransferTransmissionControlUsingAppliedMaterials"~PresentedtotheFireproofingandSafetySymposium,WesternResearchApplicationCenter,LosAngeles>CA(May1971)~4,O'Rourl,c,J.F~~"TheUseofIntumcscentCoatingsforFireprotectionofStructuralSteel",Presentedatthe.AnnualMeetingoftheAI~ChE>Philadelphia>PA(November1973)~5>TSI>INC.>TcchnicalNoteNo.75120>"Thermo-LagSublimingSystemforExtendedFitcResistanceofLPCStotadeTanks"~Januar<197S~ theexposuretimerequiredtoreachapreselectedtemperature-levelasafunctionofthecoatingthickness,incidentheatfluxandsubstrateheatcapacityforeachparticulartypeof'coatihgandmetallicsubstrate.Figure2presentsacorrelationoftheFiguredataforanintumescentcoatingappliedtoavarietyofstructuralbeamssizes.Asshown,thetimerequired~forstructuralsteelbeamstoreachthedesignlimitingtempera-tureof1000Fcanbeexpressedasafunctionof(T)(W)'(F),where:0.5TFireproofingcoatingthicknessininchesWWeightofthestructuralsteelbeamsinlbs/ftF=TotalincidentheatfluxinthousandsofBTU/hrsq-ftTheFigure2correlationshaveconsderedafireproofingcoatingthicknessrangeof0.125inchesto0.500inches,structuralbeamsizesfrom8WF31to14WF228,andatotalincidentheatfluxof29,500BTU/hrsq-ftasbeingapplicabletotheASTM-E-119flamesexposuretestmethod.Thedifferentdatacorrelationsshownfortheintumescent.masticcoatingsandthesublimationcompoundcoatingsadequatelyillustratetheverysignificanteffectofthecoatingthermalpropertiesonageneralizedengineeringcorrelation.If,orwhen,sufficientdataonthe"energyabsorptionrates"ofthevarioustypecoatingsbecomeavailable,itshouldbepossibletoexpresstheindividualdatacorrelationsasasinglegeneralizedcorrelationofthetype:afunctionof(T,AT,F,W,E)abcdewhere,tT=AT=FWFlamesexposuretimeFireproofingcoatingthicknessTemperatureriseofstructuralbeamsubstrateTotalincidntheatfluxWeightofbeamperlinearfootexposedtoflamesheatingCoatingenergyabsorptionrate.DATAANALYSES:LPGSTORAGETANKSDuetothelargescaleengulfmentfiretestsandplatetorchingtestsconductedbytheDepartmentof.ransportation-FederalRail-roadAdministrationonfullscale33,000galloncapacityLPGrail-carsfilledwithLPGproduct,andthepossibleapplicationofthesedataforfireproofingofothertypeflammableproductstoragetanks,particularattentionhasbeengiventotheTableIIexperi-AVESSONANDASSOCIhTES,INC.

~IQlVO~s,p~r~~~'EGEND~..-.":"-'...08WF31BeamsCoveredwithIntumescentMastic(1)010WF49BeamsCoveredwithIntumescentMastic(1)~14WF228BeamsCoveredwithIntumescentMastic(1)O8WF39BeamsCoveredwithSublimingCompound(5)10WF49BeamsCoveredwithSublimingCompound(6)~,~~CTimeforBeamstoreach-."300F:SublimingCompound~.Coatings40~~~~eI~~(~:--:':::.-"--'::.~~~~I20P~~~~I'I'I'~~~~A~t:I~~I~~~~~~~I~~~~~~II~~~~~~~~~~~~~I~~el~02'405'"lo.40.(T)(W)'FFIGURE2:CORRELATIONOFTHETHERHALCKARACTERISTICSOFDIFFERENTTYPEFIREPROOFCOATINGFORSTRUCTURALSTEELBEPJ'iS.2001Ie~.el~I~ill<<'.'I'.<~tw~I'-'T.~Fireproofcoatingthicknessinches-'.:-:'::'..!:.-':-F~Incidentheatflux,thousandsofBTU/hrsq-ftWeightperfootoflengthforSteelBeams,1bs/ft00~<:.::TimeforBeamsto8:.:reach1000oF:Subliming"A---,-Coating,....I.'"."Timefor'eamstoreachi.'::-':-j:;.1000F:Intumescent1the80OI60AC/1 mentaldatarelatingtothisDOT/FRAtestingprogram(4).~~~~~~~However,beforepresentingtheresultsofthedata.analysesoftheDOT/FRALPGrailcartestprograms,itmaybeofinteresttonoteafewofthecharacteristicsassociatedwithLPGstoragetankfirehazards.ItisimportanttorealizethatpastfireexperienceshowsthatwatercoolingofLPGtanksisnottotallyeffectivefortheprotectionofsuchtankswhenthetanksareexposedtofullengulfmentand/ortorchingfireconditions,especiallywhentheimpingingfireisontheLPGtankvaporspace.Itisequallyimportanttorealizethatthenewlvdeveloped"passivefireproofing"cannotdelayLPGtankBLEVE(BoilingLiquidExpandingVaporEx-plosion)foranindefinitetimeperiod.conomicconsiderations,aswellasdesignandsystemapplicationsconsiderations,dictatethatpracticaltineexposurelimitsmustbeestablishedforthese"passive",orfireproofing,protectionsystems.Theseexposurelimitsareinfluencedbythefollowingconsiderations:1.2.3.4.The"credible"amountoffuelavailabletobeburned.A"credible"rateoffuelreleaseifaspillfireisinvolved.Typeoffirecondition(s)tobeconsidered.Forexample,iXthedownwinddistanceofflammablevapor-airmixtureistobelimited,thentheLPGspillsurfaceareamustbecontrolled.ThismayrequireimpoundingofthespilledLPGattheLPGtankarea,orcloseby,witharesultantpossibilityofspillfireflamesimpingement,orhighintensityradiantheatfluxes,directlyupontheLPGtank.Theavailabilityand/orresponsetimeforemergencycounter-actionssuchasmanualshut-offofflowcontrolvalves,timeforsettingupremotecoolingwatermonitors,timeforlocalFireDepartmentstorespond,etc.ThefailureofanLPGtankexposedtoafiresituationisdirectlyrelatedtothetank'ssteelstructuralstrengthchar-acteristicsasafunctionoftankshelltemperature.Ingeneral,thestrengthofLPGtanksteelmaterialsincreasesasthesteel0temperatureincreasestoatemperaturerangeoffrom600to800F.Somewhereintherangeof650to850F,dependingontheparticular.steelbeingconsidered,thestrengthstartstodecrease.Atasteeltemperatureofabout1000F,theburststrengthofanLPGtankwillbereducedtoabout300psiginternaltankpressure.'Atabout1100F,theburststrengthcan'b'easlowas.200p'sig.Thus,prolongedexposuretofireheatingconditionscanreducetheburstpressurecapabilitiesofanLPGtankfromthenormalrangeofaboutlOCOto1250psigatanbienttemperatureconditionsto200psig,orlower,duringafiresituation.Then,dependingontheexposuretine,thesteeltemperature,thereliefvalvesetting'andcapacities,andtheamountofLPGinthetank,aBLEVEconditioncouldresult.WESSONhNDASSOCIATES,INC.

~~-13-Th'eenergystoredinanLPGtank,oranypressurevesselforthatmatter,duetointernalpressurizationisproportional'-tothevolumeavailableforproductvaporsandtheamountof.:energyavailableforreleaseperunittime.Agenerallyacceptedmethodforcalculationofthenetamountofenergyavailableistoequatethereliefvalvesetpressuretoacalculatedequivalento8TNTpercubicfootoftankvolume.Thiscanbedoneusingtherelationship:FLbsofTNT=0.00135VPPPln-Pawhere,VVolumeofLPGtank,cubicfeetP=LPGtankpressurereliefvalvesetpoint,psiaPAmbientpressure,psia.Theval'uethusderived'foraparticulartank'sTNTequivalentisusefulinestimatingtheover-pressuresresultingfromaBLEVEcondition.ThedamagepotentialofaTNTexplosionasafunctionoftheseparationdistancefromtheexplosionsourcepointcanbeestimatedfromthemaximumoverpressureatthepointofinterest.AssumingacylindricalchargeofTNT,themaximumoverpressurecanbeestimatedfromtherelationship,Pm=Po11.34185.9Z219210Z3.where,P=maximumoverpressure,psiP=Ambientpressure,psiaZ~3.967R/(TJ)RDistancefromexplosionsource,feeth'TNTequivalentweight,lbs.TheassumptionofacylindricalchargeofTNTinEquation2givesaconservativevaluefortheoverpressuresascomparedtothoseforarectangularchargeofTNT.However,thenormalconfigurationofanLPGstoragetankdictatestheuseofthecylindricalshapecharge.~Thevariation'fmaximumoverpressure.withdistanceforseveralTNTequivalentweightshasbeengeneratedfromtheEquation2andtheseresultsarepresentedinFigure3.Across-plotofFigure3ispresentedinFigure4andissomewhatmoreconvenienttousefortheestimationofthedamagepotentialduetoanLPGtankBLEVE.Forreferencepurposes,themaximumoverpressurefroma250psigLPGtankBLEVEconditionisindicatedLESSONhNDASSOCIhTES~INC.

4eII~II~~~~IllI~Il~~~~~DamagetSteelS!j~~~Idoo-~~W~'l~~IlIlIII~~,Ill~~l~ti~kt+'L.~1I~F-I~~'e'r-cenatall0~,'I-!a.lltais.<-l-7res,.Ii';iI-.i",fun.Dainge:H4eiOVQ~4~~0VVQ0~IXv~XswIVVCIIVpIEJV~Il=':~~-I-'.,:~II-::~.i~'..~~i'I!'=-,.:.bio'erate!daa~e-'Xxa~~lI~me.l&.concrete~It.'oitIpood3Qock-'-~II~~i'~I!I~~I~I.er-:.+.ass-.windowIII-~i'i~~.--~-'-':~ll~~~~~~~~~~~~~~~~)it-,~~I<<Cncl~VIVIrnIVOlioteVI<<WCIIISaVI/dODistancefromExplosionSource,feetFIGURE3:DPJ'!AGEPOTENTIAL'SFRO~!TNTEXPLOSIONS

~~~~~~0g%g!ssaaraPwalI%%ll5,$88%5'WSII,~d~kgHIIM~SEggli~%%gSEHS~MlgWISltllllWgH~~INISMIIW~INIMWWRRsaaalMN~~WWgggplFglSICIllBlBRII1W~FiI'l)IIIII'I8,goal~tglill-~s~.i.htIIIII~0 onFigure4.ItshouldbenotedthattheFigure4damage"potentialsdonotaccountfor"projectile"damagethatmightresultfromanLPGtankBLEVEcondition.Thereare,numerousexamplesintheliteratureofthecon-sequencesofLPGtankfiresandBLEVEconditions.However,themostcommonandfrequentcauseofmajortankfailuresappearstobefromsafetyreliefflarefiresburningforprolongedperiodsoftimeabovethetank'svaporspaceand/orimpingementonthevaporspaceofadjacenttankage.Areviewoftheliterature,availabletestreportsandpublishedarticlesindicatethefollowingfacts:l.Mostengulfmentfiresexhaustthetankcontentswithinonehouroffireexposure.2.Thermalcoatingsthatareapprovedbynationallyrecognizedandindependenttestingand/orfireratingagenciesare~availableforfireratingunderdirectflamescontactcon-ditionsforinexcessofatwo-hourexposureperiod.3.AgoodmediumresponsetimeforaCityFireDepartmentandset-upforapplicationofcoolingwaterforLPGstoragetanksisabout15to20minutes.4.ThemediumtimetoBLEVEforanunprotectedtankisabout14minutes(somewhatlessthanthemediumresponsetimefortheCityFireDepartment).5.Safetyreliefvalvefirescanbeextinguishedbycoolingof:thetankcontentstobelowthatpressurelevelatwhichthesafetyreliefvalvewillopen.6.NoneoftheconventionalstandardinsulationsystemsnowavailablewillwithstandalldesignrequirementgandkeeptheLPGtankvaporspacetemperaturebelow120Ftemperatureisaboutthatfor250/225psigreliefvalvesetting.7.Excessflowvalvescannotbedependeduponalonetostoptheflowoffuelduetopossiblerestrictionsinthesupplylinesandleakrateswellbelowthatnecessaryforexcess.flowvalveoperation.8'.A"passive"thermalprotectionsystem(asystemthatdoesnotrequiretheactuationofprotectiveequipmentormanpowerresponse)isjustasimportantatankdesignfeatureasthesafetyreliefvalve.-LESSONhNDASSOCIhTES,INC.

9.A"passive"thermalcoatingthataffordsatleastone-hourofprotectionshouldbeappliedtoallLPGtankagetoallowfirementoinitiateapplicationofsupplementalcoolingwater.10.Automaticfire,orheatactuated,valvesarecommerciallyavailable'andarehighlyreliable.Suchvalvesshouldbeinstalledinallliquidtransferlinesandshouldbeofthefullinternaltype.AsaresultofthelargenumberofLPGtankfiresand/orBLEVE'sthathaveoccurredandarestilloccurringinthiscountry,andperhapsdueinparttosomeidentificationofthetypesoffiresthatcausesuchincidents,theDOT/FRAsponsoredaresearchandfullscalefiretestingprogramonfullsize,andfilled,33,000galloncapacityLPGrailroadtankcars.Thistestingincludedenvironmentaltests,one-fifthscalepreliminaryfiretests,fullscalespillfreengulfmenttestson33,000gallontankcars,andhighpressureflameimpinging(torching)firetestsonsamplesizeLPGtankmaterialplatesprotectedwithmost,ifnotallavailable,thermalprotectionsystems.Someoftheprotectionsystemsfailedduringenvironmentaltests,othersfailedduringtheone-fifthscaletests,andotherssuccessfullycompletedalltherequiredtests.SincethehighpressureLPGimpingingfiretestsr'esultedinthemostsevere,butrealisticandpossible,fireheatingrates(upto67,200BTU/hrsq-ftincidentheatfluxes),coatingerosionconditions,andcoatingthermalstressratesandlevels,theremainderofthispaperwillbedevotedtothegeneralanalysisofthetwohighestperformancelevelsystemsresultingfromtheDOT/FRA~(4)experimentaltestingprograms,anablativetypecoatingandasublimationcompoundcoating.Fromtheformeran'alysesdiscussedforstructuralsteelbeams,itappearedthatthedataobtainedfromthesampleplatetorchingtestsshouldcorrelateintheformof,t=afunctionof(T,F,BT,M)abc,dwhere,t=Plateexposuretime,minutes'T=Thermalcoatingthickness,inches04T=Steelplatesubstratetemperaturerise,FFITotalincidentheatflux,thousandsofBTU/hrsq-ftW=Steelplateweightperunitareaexposedtoflamesheating,lb's/sq-fta,b,c,d=Correlatingcoefficients.Figure5presentsthecorrelatingresultsfortheablativecoatingandthesublimationcompoundcoatingexperimentalresultsobtainedfromtheDOT/FRAtorchingtestson5/8"thicksteelplatesamplesLESSONhNDASSOClATES)INC.

JS.LEGEND'TIMEFOR5/8"PLATETOREACH800F":8TDKFOR5/8"PLATETOREACH500OF&TINEFOR5/8"PLATETOREACH300FOPENPOINTS,SUBLDfATIONCOaiPOUNDCOATING~SOLIDPOINTS:ABLATIVECOATINGI,I~i~~~I'~4J2006tC4100o80ACQr////////////B///////0/'O.g',m'//////20t'~~~~~~~~~iII......../.~--/-"-/i'.I60~~.04tie!aclttimt>>,"a"I'.)>>tei/.001.002.004.01.02(INCHESOFCOATING/THOUSANDSOFBTU/HRSQ-FTINCIDENTHEATFLUX7FIGURE5:CORRELATIONOFDOT/FRALPGTORCHINGTESTSRESULTSON5/8"THICKLPGTAhKPLATEl'fATERIAL intheformofplateexposuretimeexpressedasafunctionofthe'oatingthicknessdividedbythetotalincidentheat,fluxwighthemetalplatesubstratetemperaturesof300,500,and800F.'sacorrelatingparameter.ThefivetestpointsshowninTableIIforthesubt.imationcompoundtypecoatingresultedinanex-cellentlinearcorrelationfortheFigure5log-logtypeofpresentation.Thetwoexperimentaltestpoints(ateachofthethreenotedplatetemperatures)fortheablativetypecoatingshowninTableIIandtherelativelocationswithrespecttothesublimationcompoundcoatingcorrelationsforeachtemper-ature,indicatealinearcorrelationfortheablativetypecoatingthathasthesameslopeasthatofthesublimationcom-poundtypecoating'.Youmightrecallthatthischaracteristicwasnottrueforacomparisonofthesublimationcompoundcoatingandtheintumescentmasticcoatingsforsteelstructuralbeams,whereintheslopeswerequitedifferent.AcloseexaminationoftheFigure5datacorrelationsindicatestwoimportantfeatures;one,theparallelismofthelinearlines.shownforthe300,500,and800oFplatetemperaturesindicatedthatitshouldbepossibletocollapsethethreelinestoasinglelinecorrelationincorporatingplatetemperatureriseasageneralcorrelatingparameterand,two,thesublimationcompoundcoating,takingagivenplatetemperatureriseatagivenperiodofexposure,hasahigherthermalperformancecapabilitythandoestheablativecoating,usingtherequiredcoatingthicknessasameasureofthecoatingthermalperformancecapabilities.Forexample,foratwo-hourexposureatanincidentheatfluxof30,000BTU/hrsq-ft(thisheatfluxcouldcomefromanytypeoffiresituation:directflamescontact,flamesimpingementunderpressure,oronlyrad-iativeheatloads)andalimitingplatesubstratetemperatureof800oF,thesublimation.compoundcoatingrequiresonly66/.ofthethicknessrequiredbytheablativecoating(0.180inchesversus0.273inches).IfwemakeanassumptionsimilartothatutilizedfortheFigure2generalcorrelationforstructuralsteelbeamswhereinitisassumedthatthemetalsubstrateheatcapacitycanbecorrelatedasthebeamweightperlinearfoot,itshouldbepossibletoobtainacompletelygeneralizedcorrelationforthesublimationcompoundcoati-.gwhenappliedtometalplatesubstrates.AsisshomxbyFigure6,suchacorrelationispossible,andcorrelatesalltheTable.II'testdatafor5/8".thicksteelplatequitewell.Asshown,theexposuretimecanbeexpressedasageneralfunctionofthesublimationcompoundccatingthicknesstimesthosubstratete-...peraturerisetoanexponentof0.70,timesthemetalplatesubstrateweightinlbspersq-ftofexposedsurfaceareatoan0.50exponentdividedbythetotalincidentheatfluxinthousandsofBTU/hrsq-ft.Thus,theFigure6LESSONANDASSOCLAYES%INC.

loto~-20-~~I~~I'I~~~~~II00,~,Ir0TEST~-.-OTEST~':..'.4TESTI'~~~I~~~~.~.~.o~0~~~~)~~POINTSFOR300FMETALSUBSTRATEPOIXi'TSFOR500F~iiETALSUBSTRATEPOINTSFOR800FiiIETALSUBSTRATE~~~~~~~~~~c-..[~...I'~~~~~~~~~~~~~~~~~~~200~~~~1I~~~~~~~~~~so~I~I~~~~I~[~~II~~~~1I~~l~~~~I~~I~i~.,L.I,~,~L~o[o~~~~~~~~I~'~to'~1000"}'I'~~I~~~~I~"IlIl~ll[~~'~Ifo~~oIII~~I~~~~~~~600Io~~1~~~~~\~~~~~~I.~r---e~~~2010Po0o~~~~o~ThermalCoatingThickness,inchesTemperatureRiseofMetalSubstrate,OFXncident.HeatFlux,ThousandsofBTU/HRSQ-FTWeightofMetalSubstratePlate,abs/sq-ftofplatesurfaceareaexposedtoheatflux~I~,l~~~~1~I~)~~~~2o~~~~I~o~~~~~~~~~0.5j(F)~t~~o~o0.11.01020XGURE6:GENERALIZEDCORRELATIONFORTHETHERK%LEFFECTIVENESSOFTIIESUBLI1ITATIONCO.PO&i'DCOATINGAPPLIEDTOASUBSTRATEOFCARBON.STEELPIXTE~~o~~~~;.o~~IiI correlationcanbeusedforengineeringdesignpurposesforthedeterminationoftherequiredsublimationcompoundcoatingthick-nessforanygivenfiresituation,givenmetalplatesubstrate"thickness',andspecifiedallowablesubstratetemperature.TheparallelismoftheFigure5correlationsforthesub-limationcompoundcoatingandtheablativecoatingalsosuggeststhataparameterexpressingthe"energyabsorptionrate"ofthetwotypecoatingcouldbeusedtomaketheFigure6generalized'orrelationapplicablefor.bothtypecoating.However,thishasnotbeendoneasyetduetoalackofknowledgeontheexactenergyabsorptioncharacteristicsofthetwocoatings,butcanbedoneoncethischaracteristicisdefined.ToillustratethepotentialusagefortheFigure6datacorrelation,letusassumethatwewishtothermallyprotecttheroofofaparticularproductstoragetankfromthethermalradiationdueofanadjoiningtankfiresituationforaperiodofone-hour.Typicalnumbersapplicabletosuchasituation.wouldbeasfollows:l.Incidentradiantheatflux:12,500BTU/hrsq-ft2.Roofthickness:0.250inchesofcarbonsteelplate(10.2lbs/sq-ft)3.Designallowablerooftemperature:350F(70Fambient)4.Protectwithsublimationcompound.coating.FromFigure6at60-minutesElapsedExposureTime,wereadafigureof2.0.Thus,or2.0~(T)(4T)(W)'(F)T=2.0(12.5)/(280)'10.2)T~0.152inchesofsublimationcompoundcoating.Basedonthepreceedingdiscussionsandengineeringdatacorrelations,itcanbeconcludedthatLPGtankagecanbethermallyprotectedwitha"passive"fireproofingcoatingsystemthatexhibits'hefollowingperformancecapabilities:l.The'assiv'ethermalcoatingmustkeeptheLPGtanksteeltemp-.eraturetobelow800oF,foraperiodof..two-hourswhen;,thetankisnotmorethan807.fullofliquidproduct,andthetankis'exposedtodirectflamesimpingementfromaspillfirebelowtheLPGtankhavingthefollowingcharacteristics:a.Incidentheatfluxoffrom40,000to50,000BTU/hrsq-ftWESSONhNDASSOCIATES,INC.

~~j-22-b.Flamevelocityontheorderof100ft/sec-"--"-c.DistancefromspillsurfacetoLPGtankbottomis3-ftorless.2.Thethermalprotectivecoatingshouldbedurableintheintendedexposedenvironmentalserviceconditionsforaperiodof20years,withthetopcoatrenewalbeingatleastfivetosevenyears.Duringthisserviceperioditshouldnotdust,flake,chip,crack,orspalloffduringnormalserviceconditions.3.4.Duringfireconditions,theresidualcoatingshouldnotspallfromthethermalshockduetosupplementalwaterstreamcooling.Thethermalcoatingmaterialsshouldbenon-toxicandentirelynon-flammable.5.6.Thematerialshouldnotcontainanyasbestos.Thematerialshouldnotbecorrosivetostructuralsteels.7.9.10.Thematerialsshouldberesistanttochemicalspillsandfumesfromthosechemicalsnormallyassociatedwithpetro-leumandpetrochemicalprocessingandstorageplants.Thematerialsshouldbeapplicablewithairlesssprayequip-mentandthecoatingshouldcurewithinamaximumtimeperiodofthreedays,at75oFand50%relativehumidity.Thematerialshouldhaveabondingstrengthofnotlessthan100psi.Whenusedforprotectionoflowtemperatureflammableliquidstorageortransferlinesl,'suchasLPGorLNG),submergenceand/orliquidspraycontactwiththestoredproductshouldnotresultinanyadverseconsequencesonthefireproofingcapabilitiesofthecoating.Further,thecoatingshouldbeabletowithstandsimultaneousexposuretothelowtemp-eratureliquidsanddirectflamescontactconditionswithoutlossofprotectivecapabilities.CONCLUSIONSEasedupontheexperimentaldata,dataanalyses,anddis-cussionspresentedherein,itcanbeconcludedthat:ItispossibletogeneralizetheexperimentaldataobtainedfromspecificratingtestsonspecifiedstructuralsubstrateswithspecifiedcoatingthicknessesexposedtodirectflameWVEssoNAM)AssocIhTEsiINc.

contactfireconditionsintogeneralizedengineeringcor-----'elationsforeachtypeofsteelsubstrateandcoatingwhichexpresstheprotectiontimeasadirectfunctionofthe....-':-"'coatingthickness,substratetemperaturerise,substrateheatcapacity,andtotalincidentheatfluxes.Theseengineeringcorrelationscanthenbeusedforthedetermin-ationoftherequiredtypeofcoatingthicknessforagivensubstrate,givensubstratedesigntemperatureandgivensub-strateheatcapacityunderanytypeoffireheatingcondition(flamecontact,impingingflames,and/orflamesradiation).Basedontheexperimentaldatapresentedin'thispaper,andnowavailableintheresearchliterature,thesublimation'ompoundtypecoatinggivesasuperiorfireproofingperformance,asmeasuredbythethicknessofcoatingrequiredwithallotherapplicableparametersheldconstant,thananyotherfireproofingcoatinganalyzedinthispaper.REFERENCES4.8.2.O'ourke,J.F.,"TheUseofIntumescentCoatingsforFireProtectionofStructuralSteel",Presentedatthe1973AnnualMeetingoftheA.I.Ch.E.inPhiladelphia,PA(November14,1973).Kayser,J.N.,"TestsofFireproofingMaterialsforStructuralSteelforRefineriesandChemicalPlants",Presentedatthe.1973AnnualMeetingoftheA.I.Ch.E.inPhiladelphia,PA(November14,1973).Feldman,R.,"FireRetardancyandHeatTransmissionControlUsingAppliedMaterials",PresentedtotheFireproofingandSafetySymposium,>lesternResearchApplicationCenter,LowAngeles,CA(May27,1971).BallisticResearchLaboratories,AberdeenProvingGround,YD(Anderson,C.,Townsend,V.,Markland,R.,andZook,J.),"ComparisonofVariousThermalSystemsfortheProtectionofRailcarsTestedattheFRA/BRLTorchingFacility",InterimReportNo.459totheDepartmentofTransportation,FederalRailroadAdministration,Uashington,DC{December1975).FactoryMutualResearch,"FireEnduranceTestonSteelColumnsProtectedwithThermo-Lag330-1Coating",ReporttoTSI,Inc.,St.Louis,MO(November6,1972).FactoryMutualResearch,"ASTME119FireEnduranceTest(Modified)Structural'SteelColureProtectedbyThermo-Lag330-1Coa'ting-DesignCT-36",ReporttoTSI,Inc.,St.Louis,MO(April1974).FactoryMutualResearch,"ExploratoryFireEnduranceFireTestonStructuralSteelColumnwithThermo-Lag330-1Coating".ReporttoTSI,Inc.,St.Louis,YO(November30,1973).FactoryMutualResearch,"ExploratoryFireEnduranceTestonStructuralSteelColumnwithThermo-Lag330-1Coating",ReporttoTSI,Inc.,St.Louis,MO(November30,1973).QESSONhNDASSOCIhTES,INC.

,~tv'/AA&(le~g-gqypzjgpTsAgooNg r~-.p~r~c.wA>PLEE-E-5-LillfjAR~8"ILII,III.ElQ,25'-IOIIIIIIIIIIIgNN'KC?IIIII0I/DIA)~~LIIIIZZFZAIREH<FLO-TWO+<Gl,'P'RKF,PM/QI2-34-3+'2-$+$6>q'i1-0"-naoroHDDIPfIKt625'-IoIii8)2C'ARgXqSTALZe(IWAIIHOLg5ONKRAc>wslX)QSE.CTlo(46-I:.lilt1BCSPLlkRl.~F-FIPazotlE4-ll8LTIPIRE~Kg-llNI'IRPEVALL5-4 SIZE(WIDTH)III'EDVINYLGRIP'2SINGLELEAFSTEELDIAMONDPATTERNPLATEReinforcedfor150lbs.persquarefootliveload.JJKIJ0II-6ZIJJIJNA.III'FLUSHLIFTHANDLEISTEELSTRAPANCHORIIIIIIIYES"DIAMONDPLATECOVERIIIIId~J'sGrII'I(IIIIIIItujIRCOVINYLGRIPA.AUTOMATICNOLO.OPENARMIIIORSION/BARSHINOCTORSI~BARSSTAINLESSSTEEL4--)SLAMLOCKWITHU---BRASSHANDLEaIIGeneralContractor,PleaseNote:Becarefulnottorackortwistframe~e~settingunit.Blockupandshimtheframeifnecessarytobesuredoorrestsevenlyonframeallaround.FaCtOQFiniSh:Steel-redoxideprimerHardware-cadmiumplatedsteelPLAN.VIEWSECTIONB-B(CoverinOpenPosition)ManufacturersofDoorsforSpecialServicesP~THEBILCOCOMPANYHcwHaven,Connecticut06505NREMOVABLEKEYWRENCHI/4"STEELDIAMONDPLATECOVER0-<SLAMLOCKGII~SIZE(WIDTH)HNGEMASONRYOPENINGFQl/4"XS"XS"STEELANGLEFRAMEfIIEltilTlTGRSIGN5g7i5ilITggQiiST:iI'2.8IJ-alilt'TEELg53.ilialTiANCHORaeftuufTITTARCH'T.ORENG'RHFEIIITIILEICTIQl2'4"x2'4"Q22'4"x2W'galx3J+I3'4"x3'4"KHlH6650HaOOP&l~<4BLED,AlAW~~s~%aERARThisdrawingisthepropertyofTheBilcoCompanyandincorporatesspecificationsandpatenteddesignsinwhichTheBilcoCompanyhasproprietaryrightsand,accordingly,isnottobcreproducedwithouttheexpresswrittenconsentofTheBilcoCompany.PURCHASEORDERPROJECTGEN'L.CONTRACTORPURCHASERBILCOREPRESEHTATIVDWG.NO.ATEDATE i)'L~};p%S

+plCANELfciAMERICANELECTRICPO'WERSERVICECORPORATIONOHERSystswMay15,1984suszEcTiD.C.CookNuclearPlantFireRatedFloorHatchesRFC's01-2676and02-2692V.DelFaveroF.S.VanPeltgJI.InresponsetoItem4,"Provideanyalternativestotheinsulationorcompensatorymeasuresthatmaybeavailable",oftheNRClettertoMr.DolandatedApril4,1984,thefollowingmeasureswereconsidered:Provideaverticalfireratedenclosureabovethehatch.Thisisnotpossibleduetothelimitedspaceandcloseproximityofelectricalcabinetswhichrequireaccessformaintenanceandoperation.2.3~Layingafireratedblanketabovedoor.Thisimpedestheoperationofthehatch,andcreatesapersonnelsafetyproblem.Provideaverticalfireratedenclosurebelowhatch.Thisisnotpossibleduetomanyinterferenceswithcables,conduit,troughs,andcabinets.4~5.Addahorizontalfireratedpanelbelowhatch.Thereisaninterferencewiththeaccessladderandapersonnelsafetyproblemofaccesstothehatch.Replacehatchwithafireratedhatch.Noprefabricatedfireratedfloorhatchisavailable.WehavecontactedTheBilcoCompanyaboutdesignandtestingofafireratedfloorhatch.(See.attachedcommunications)V.DelFaveroVDF:bcc::STFoxWQ<~~useaCVCVraa AMERICANELECTRICPOWERServiceCorporationAEP1RiversidePlaza$614)223-1000P.O.Box16631Columbus,Ohio43216-6631March131984RobertLyons,PresidentTheBilcoCompanyP0Box1203NewHaven,Connecticut06505RE:D.C.CookNuclearPlantbc=0-4aeo*

DearMr.Lyons:

InarecenttelephoneconversationyoumayrecallourrequestthatTheBilcoCompanysubmitaquotationforfurnishinga2'-6"x3'-0"floorhatchbearinganUnderwriters"A"label.ItisunderstoodthatyoudonotmanufactureaU.L.ratedfloorhatch,however,asAEPanticipatesthelikelihoodthatretro-fittingofseveralBilcoinstallationsinthesubjectplantmayberequired,weneedtomakeallowanceforsuchacontingency.IfthisrequestisagreeabletoyoumaywesuggestthatyourquotationalsoincludethecostofonesubmissiontoU.L.fortestingandlabelingandaseparatepriceforeachsuccessiveU.L.applicationasmaybenecessary.Atafuturedate,ifAEPbecomescommittedtothereplacementofhatchesasreferredtoabove,theprogramwillprobablybeindustrywideandtheseratedhatcheswillbeindemand.Asalongstandingpurchaserofmanyofyourproducts,wehopethatyouwillbeabletofurnishuswiththedesiredpricingdata.Ifyourequireanyfurtherinformation,pleasedon'thesitatetocontactus.Yourearlyresponsewill"begreatlyappreciated.Verytrulyyours,A.C.MacksoudChiefArchitectACM:b THEBILCOCOMPANYP.O.BOX1203NEWHAVEN,CT065O5March21~1984Mr.h.C.MacksoudChiefArchitectAmericanElectricPowerServiceCorporation1RiveraidePlazaP~0~Box16631Columbus,Ohio43216%631RE:D.C~CookNuclearPlanttg-0-4200A

DearMr~Macksoud:

ThankyouforyourletterofMarch13,1984concerningyourrequire-mentsforafloordoortocarryanUnderwriters"A"label.'RehavecontactedbothUnderwritersLaboratoriesandFactoryMutualEngineeringDivisionwithrequestsforcoststofiretestoneofoursingleleafJ-3doors,size2'6"x3'0",andalsooneofourJ<<4doors,size5'0"x5'0",indoubleleafdesign.JustassoonasIreceivesomeinformationfromthemIhopeIwillbebetterabletoansweryourletterandIwillbeintouchwithyouatthattimeYourstruly,THEM.ANY\ipRobert:QonRJL:wfgRECEfVFDMAR231984ArcRtechu.dS~tt~'lANIANDMAIHOCFCc07wasecacvaccgwc'avcurnklklcl'TilIITIhh'IQ'1e%t'1 eI:*4

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