ML17321A100

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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DRYFILMCOATINGTHICKNESSES OFTHERMO-LAG 330-1SUBLIMING MATERIALAPPLIEDTOSTEELHATCHCOVERSFORTHREEHOURFIRERATINGPreparedbyWessonandAssociates, Inc.P.0.Box1082Norman,Oklahoma730702iPDRADQCK05000315PDRWESSONANDASSOCIATES, INC.February15,1984

DRYFILMCOATINGTHICKNESSES OFTHERMO-LAG 330-1SUBLIMING MATERIALAPPLIEDTOSTEELHATCHCOVERSFORTHREEHOURFIRERATINGI..INTRODUCTION Thepurposeofthisreportistopresentthecalculated minimumdryfilmcoatingthicknesses of,THERMO-LAG 330-1Subliming Materialappliedtosteelhatchcoverswhichareprovidedinthefloorsofnuclearpowerfacilities.

Thesehatchcoversareusedtosealtheconnecting passageways betweentwofloorlevelsorbetweenafloorandavaultbeneaththefloorinthesenuclearfacilities.

Theminimumdryfilmcoatingthicknesses havebeencalculated toprovideathreehourfireratingwhensubjected tothefirecondition specified byASTME-ll9TestMethod.Inthistestprocedure, thetime-averaged incidentheatfluxforathree-hour exposureis42,000Btuperhourpersquarefoot.Thebasisforthedetermination oftheminimumdryfilmcoatingthicknesses fortheTHERMO-LAG 330-1Subliming Materialappliedtoflatplatesisanengineering correlation developed fromexperimental resultsfromfiretestsconducted onthematerial.

Theexperimental datausedinthecorrelation includetheresultsoffiretestscon-ductedby'everal independent organizations suchastheUnderwriter's Laboratory',

theU.S.'epartment ofTransportation (FederalRailrbadAdministration),

MobilOilCorporation andWessonandAssociates, Inc.Theminimumdryfilmcoatingthicknesses havebeencalculated forhatchcovershavingthicknesses of3/16,3/8and1/2inches,fireex-posurefromonesideonlyandsimultaneous fireexposureonbothsides0ofthehatchcover.Thetemperature risesusedincluded250FforLESSONANDASSOCIATES, INC.

0personnel considerations and930Fformaintaining thestructural integrity ofthesteel.II.ENGINEERING CORRELATION FORFLATSTEELPLATESThethermalperformance characteristics offireproofing materials suchasTHERMO-LAG 330-1Subliming

Material, THERMO-LAG 290Subliming

Material, CHARTEK59,KOROTHERM andPYROCRETE 102havebeenfoundtocorrelate as:wheret=afunctionof(T,QT,W,F)t=fireexposuretime,minutesT=dryfilmcoatingthickness offireproofing material,'

inches0QT=temperature riseoftheprotected metalsubstrate, FW=effective heatcapacityofprotected metalsubstrate, poundspersquarefootofexposedareaF=totalincidentheatflux,thousands ofBtuperhourpersquarefoot.Experimental firetestdataexpressing thefireexposuretimeasafunctionofthefireproofing materialcoatingthickness, thetemperature riseoftheprotected metalsubstrate, theweightoftheprotected metalsubstrate'nd thetotalincidentheatfluxhavebeenusedtodeveloprempirical engineering correlations fortheTHERMO-LAG 330-1Subliming Materialappliedtovarioussubstrates suchasflatsteelplates,pipesandstructural steelmembers(I-beams).

Therangeoftotalincidentheatfluxeshavevariedfromalowof10,000Btuperhourpersquarefoottoahighofabout95,000Btuperhourpersquarefoot.Thecoatingthicknesses havevariedfromalowof0.125inchestoahighofabout1.25inches.Theengineering correlation expressing theexposuretimeofaprotected steelplateasafunctionofthecoatingthickness, temperature riseofthemetalsubstrate, theeffective heatcapacityoftheprotected sub-strateandthetotalincidentheatfluxisWESSONANDASSOCIATES, INC.

1.3356t=23.002(T)(QT)(W)/(F)(2)whereWiFexpressed inpoundspersquarefootofprotected flatplateexposedtbtheincidentheatflux.Theengineering correlation ispresented inFigurel.Asnotedonthisfigure,iftheprotected sub-strateisexposedtoafirecondition onbothsides,theeffective heatcapacity, W,isbasedonone-halfthethickness oftheplate.4III.INCIDENTHEATFLUXESFROMFIRESTheincidentheatfluxesfromtheASTME-119TestMethodandfromflammable liquidspillfiresarewidelyusedforthedetermination oftherequiredfireproofing coatingthicknesses forvariousprotected steelsubstrates.

ASTME-119TestMethod:TheASTME-119TestMethodusesaspecifictime-temperature relation-sshipfortestingthefireresistive.

capabilities ofvariousfireproofing materials.

Therequiredtime-temperature relationship ispresented inFigure2.Asshowntheinternalairtemperature ofthethetestset-upstartsattheprevailing ambientairtemperature, reachesatemperature 0of1700Fattheendofthefirsthourofexposure, atemperature of1850Fattheendofthesecondhourofexposureandatemperature of0ofabout1950Fattheendofthethirdhourofexposure.

Thisspeci-0fiedtime-temperature profiledoesnotrepresent thetime-temperature profileforatypicalhydrocarbon spillfirewhereinthetemperature 0withintheflamezonemayreachatemperature ofabout2200Formorewithinaveryshortperiodoftime(onetothreeminutes).

Thus,theASTME-119TestMethoddoesnottrulyrepresent theenvironment ofaflammable hydrocarbon fire..Thetime-heat fluxrelationship corresponding tothetime-temperature profilespecified bytheASTME-119TestMethodispresented inFigure3.Asindicated onthisfigure,theintegrated time-averaged incidentheatfluxesare24,500Btuperhourpersquarefootforthefirsthourofexposure, 34,500BtuperhourpersquarefootfortwohoursofexposureWESSONANDASSOCIATES, INC.

4VFIGURE1:CORRELATION OFTHETHERtRLPERFORMANCE CHARACTERISTICS OFTHERMO-LAG 330-1SUBLIMING MATERIALAPPLIEDTOSTEELPLATESANDPIPESNOTE:Foranglesorplateexposedonbothsides,useW~@eightofmetalsub-strate,lbs/sq.ft ofexposedareabasedonone-halflegorplatethickness 200~Testpointsfor300Fmetalsubstrate 00~Testpointsfor500Fmetalsubstrate 0Testpointsfor800Fmetalsubstrate 100II'I~IIII~~~~~III~'~IsIo10~~~IE~~~~III~C'I'O'II'>>23o002(T)(QT)(W)/(F)T~THERMO-LAG 330-1Coatingthickness, inchesDT~Temperature RiseofMetalSubstrate, F0FsWeightofMetalSubstrate, lbs/sq.ft ofexposedsurfaceTotalIncidentHeatFlux,thousands ofBtu/hr-sq.ft 0.110(T)(DT)(W)/(F)10WZSSONANDASSOCXATES INC.4 FIGURE2:ASTME-119TESTMETHODTIME-TEMPERATURE PROFILE(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'IIIII i)'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(INCIDENTHEATFLUXLEVELOFFIRESPECIFIED BYASTME-119TESTMETHODASAFUNCTIONOFFIREDURATION/EXPOSURE TIMEII'(~: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-AVERAGED INCIDENTHEATFLUXES'!l:~~~~ONE-HOUREXPOSURE:

24,500Btu/hr-ft 2TWO-HOUREXPOSURE:

34,500Btu/hr-ft 2THREE-HOUR'EXPOSURE:

42,000Btu/hr-ft 2I!@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.

Hdrocarbon PoolFireTotalHeatFluxes:Itmustbeemphasized thatallliquidhydrocarbon firesdonotproducethesametotalheateffects.AsshownbyTable1,different liquidhydrocarbon flameshaveverydifferent heatingeffects.Forexample,afireinvolving methanolwillonlyproduceatotalincidentheatfluxofabout12,000Btuperhourpersquare.footwhereasafireinvolving LPGcouldproduceatotalheatfluxofabout40,000Btuperhourpersquarefootforarelatively largediameterspillfire(firediameters inexcessof30feet).Sincethetotalincidentheat,fluxappearsasalinearterminEquation(2),itisveryimportant tospecifyorknowthetypeoffireforthedetermination oftherequiredfireproofing coatingthickness.

IncidentHeatFluxUsedinDetermination ofCoatinThicknesses:

Thethreehourfireratingpresented hereinhasbeenbasedontheincidentheatfluxlevelassociated withathree-hour exposuretothefirespecified inASTME-119TestMethod.Thetotalincidentheatfluxusedtocalculate thecoatingthicknesses was42,000Btuperhourpersquarefoot.IV.REUIREDTHICKNESSES FORSTEELHATCHCOVERSAcompletelistingofthecalculated coatingthicknesses ofTHERMO-LAG 330-1Subliming Materialappliedtosteelhatchcoversispresented inTable2.Fourcasesarepresented tocovervariousaspectsoffireexposureandtemperature risesofthesteelhatchcovers.Thecoversareassumedtobeexposedtoafirefromonesideonlyandalsotoafirefrombothsidessimultaneously..

Thetemperature risesconsidered 00were250Finconsideration ofpersonnel safety'and 930Finconsidera-tionofstructural integrity ofthecovers.Itshouldbepointedoutthatthedryfilmcoatingthicknesses presented inTable2donotincludea10percentagingandweathering allowance WESSONANDASSOCIATES, INC.

TABLE1TYPEOFFUELMAXIMUMHEATTRANSFERFROMFLAMESTOCOLDTARGETRADIANT(BTU/HR-FT.SQ.)CONVECTIVE TOTALMethanolAcetoneHexaneCyclohexane JP-4:SmallSpillFireJP-4:LargeSpillFireBenzolLPG:SmallSpillFireLPG:LargeSpillFireLPG:Impinging FireLNG:SpillFireonLandLNG:SpillFireonWaterEthylMercaptan T"ButylMercaptan EthyleneButhylene Butadiene CarbonMonoxideVinylChloride5,00010,00022,50031,00023,70031,00039$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, represent theabsoluteminimumrequiredcoatingthick-nesstoprovidethespecifedfirerating.Thisallowance isbasedonlongtermenvironmental testingprogramsconducted byUnderwriters'aboratories, U.S.AnnyBallistics ResearchLaboratories andcommercial usersinthehydrocarbon processing industry.

Therefore, toprovideanallowance foragingandweathering oftheTHERMO-LAG 330-1Subliming

Material, thecoatingthicknesses presented hereinshouldbeincreased byatleast10percent.WESSONANDASSOCIATES, INC.

TABLE2MINIMUMDRYFILMTHICKNESSES FORTHERMO-LAG 330-1SUBLIMING MATERIALAPPLIEDTOSTEELHATCHCOVERSBasisforFireRatin:Three-hour exposuretofirecondition specified byASTME-119TestMethod2HeatFlux=42,000Btu/hr-ft HatchCoverThickness inchesExposure*

Condition DryFilmCoatingThickness inInches**250FDT930F~T0.18750.3750.500singlesinglesingle1.4951.0550.9150.5950.4200.3650.18750.3750.500doubledoubledouble1.4951.2950.5950.5152.1100.840*Denotesfirefromoneside(single)orfirefrombothsides(double).**Doesnotincludeanyallowance foragingandweathering ofmaterial.

WESSONANDASSOCIATES, INC.10 4~g~~~Sub...itted toButane-Propane News:April1976THERt'MEFFECTIVENESS OFVARIOUSFIRERESISTANT COATINGSAPPLIEDTOSTRUCTURAL ST"ELSEXPOSEDTODIRECTFLAYERSCONTACTAND/ORRADIATIVE HEATFLUXESH.R.WessonWesson6Associates, inc.P.0.Box1082Norman,OK73069INTRODUCTION Therapidlygrowingacceptance offireresistant coatingsforthermalprotection ofstructurals steels,flammable productstoragetanks,pressurevesselsupportstructure, amongotherapplications, hasplacedthisuniquefireproofing conceptinanapprovedposi-tionforextensive usageintheareaof"exposure control"forstructures thatcouldbeexposedtodirectflamesimpingement, freeburningpluspressuretorchingconditions, and/orprolonged periodsofhighintensity radiative heatfluxes.Theinherentreliability andlowmaintenance costsforthis"passiveconcept"ofexposureprotection, togetherwiththelowperformance levelofconventional watercoolingsystemsunderflameengulfment and/orhighpressureimpinging ortorchingtypefireconditions-,

havealsogiv..thesefireproofing coatingsaveryhighcost-effective, orcost-benefit, characteristic forhighheatintensity applications.

Thesetypecoatingsarealsofindingapplications wheresimultaneous lowtemperature (cryogenic liquidimpinging conditions) andhightemperature (flamescontactconditions) protection isrequiredforthestructural steelsinLPG,LNG,andSNGfacilities.

Thedifferent typesoffireproofing coatingsthatarecommonlyavailable, theresultsof.extensive firetestingonthesecoatings, andengineering correlations oftheexperimental datathatcanbeusedfordetermination oftherequiredcoatingthicknesses foradesiredperiodofprotection invariousheatingenviron-.mentsarepresented anddiscussed herein.GENERALTYPESOFFIREPROOFING COATINGS=Themostc'ommonly acceptedfireproofing coatingmaterials includethefollowing:

WESSONANDASSOCIATES, INC.

~~~~~I2.CementCompounds:

Concrete, gunite,andsimilarconcrete'asecompounds providegoodfireexposureprotection duringbothdirectflamescontactandhighintensity flamesradia-tioncond':ions forextendedperiodsoftime.Ingeneral,however,thecementcompounds arequiteheavy,areexpensive toinstall,insomeapplications arecorrosive, andingeneralexhibitpoormechanical bondingproperties betweenthesub-strateandthecementcompound.

AblativeCoatings:

Thesetypecoatingsprovideexcellent fireexposureprotection forstructural.

steels.Thefunda-mentalprinciple istoapplyacoatingthatgradually erodesduetotheabsorbedenergyinputfromafirecondition.

Tochangetnevirginsolidcoatingintoagascomposite requiresheatinputthatwouldotherwise beabsorbedbythestructure beingprotected.

Thetemperature riseoftheprotected struc-tureisretardedindirectproportion totheablativecoatingthickness anditsthermalproperties.

Theincorporation ofceramic-like intumescents

'haveresultedinatoughmicroporous charlayerwhichprovidesadditional insulating properties whilemostoftheheatinputisrequiredforthephysicaltransformation ofthebasematerial.

Themajordisadvantages ofthesetypeablativecoatingsappeartobethecomplexity oftheapplication processandthefinalinstalled coatingcosts.3.Subliming Compounds:

Thesubliming compounds provideapro-tectedsubstrate temperature basedonthetemperature ofsub-limationforeachparticular

compound, thethickness ofthecoatingmaterial, theheatcapacityofthesubstrate, thecoatingthermalproperties, andthedegreeandtimeofheatexposure.

Ingeneral,-

thesubliming compounds formaverytough,estheticcompoundthatisverytightlybonded(bondingstrengthof100psiandmore)totheprotected steelsurface.Anotherprimeadvantage ofthesubliming compounds isthattheyarenotadversely affectedbyprolonged exposuretolowtemperature liquidssuchasLNGandLPG,aswellassimultan-eousexposuretosuchlowtemperature flammable liquidsandresultant flamescontactheatingeffectsfromliquidspillfires.Theseadvantageous thermalproperties haveresultedintheuseofthesubliming compounds atsomeLNGFacilities fortheprotection ofcarbonsteelstructures, including theactualLNGstoragetank,.thatcouldbesubjecttoLNGsub-mergenceand/orLNGliquidsprayimpingement aswellasdirectLNGspillfireflamescontact.Thesecoatingsmustbeappliedtospecified typesofprimepaintedmetalsurfaceswithairlesssprayequipment duringrelatively warmanddryatmospheric conditions (above40Fandnotduringrains).LESSONANDASSOCIhTES, INC.

4.Department ofTransportation agingandenvironmental testsgivethesetypecoatingsa20-yearlifewhenproperlycuredandthetop-coatrenewedeveryfivetosevenyears.Inturnescent MasticCompositions:

Themostcommonofthesetypecoatingsareamodifiedvinyl,heavy-bodied masticcontaining inorganic fibersinanaromaticsolventblendandareinforced epoxy,twocomponent, 100percentsolids(nosolvent)spraysystem.Ingeneral,thesetypecoatingsreactbyabsorbing heatinachemicalreactionwhichgenerates afoam-char systemontheflamesexposedsideofthecoating.Additional heatinputisusedtodrivetheliberated gasesthroughthematrix.Thefoam-char isalsoaneffective thermalinsulator.

Alloftheseheatabsorbing and/orheatflowretarding mechanisms servetokeepthesubstrate belowitsallowable ratedmaximumoperating temperature.

Theperiodofsubstrate protection dependsonthecoating.thickness, theapplicable thermalpropertes,andtheperiodandintensity ofheatexposure.

Theheatcapacityoftheprotected sub-stratealsosignificantly affectstheperiodofprotection foragivencoatingthickness.

Likethesubliming compounds, thesemasticsdonotsufferanyadverseconsequences whensubjected toLPGandLNGcontact,andarebeingusedforthermalprotection ofsteelstructures associated withLNGstoragetanks.Onedisadvantage ofthesetypecoatingsappearstobethegreaterthickness.

requiredforthesameperiodofprotection xnagivenfiresituation.

Forexample,thepublished resultsoftestsusingtheASTM-K-119 TestMethodindicatethatusinga1000Ftemperature fora8';iF31beamasabasisforcomparison, aQ"thickcoatingofatypicalvinyl-base typeintumescent masticwillgivea"two-hour"firerating,.a5/8"thickcoatingoftheepoxy-based intumescent masticwillprovidea"two-hour" firerating,andaQ"thicksublimation compoundcoatingwillgiveafireratingof"twoandone-half" hours.Anotherdisadvantage ofsomeoftheintumescents appearstobethepropensity oft'eactiveingredients toleachoutoverprolonged periodsofexposuretooutdoorenvironmental conditions.

Oncesuchaleachinghasoccurred, theprotection timeintervalprovidedbysuchcoatingsissignificantly reducedovertheinitialratingperiod.Asindicated above,theheatcapacityoftheprotected sub-'stratesignificantly

'affectstheperi'odofprotection piovidedbyagivencoatingthickness.

Anexcellent exampleofthiseffectwasgivenbyO'ourke(1)inthe1973AnnualA.'I.Ch.E.

symposium onthefireproofing ofstructural steels.Foreaseofreference, Figure1presentsthiseffectforwideflangestructural steelbeams.WEssoNhNDAssocIhTEs, INc.

,1,)I1/2C~RIC3A4MO'UOMM7/Z63/8>/161/43/161/81/168WF31STRUCTURAL BEAM~10WF49r14MF228///REF.:O'ourke,J.F.,"TheUseofXntumescent CoatingsforFireProtection ofStructural Steel"20.406080100120140160180200TIMEFORPROTECTED BEAMTOREACH1000F-minutes FIGUREl:EFFECTOFINTUMESCENT MASTICCOATINGTHICKNESS ONTHEEXPOSURETIME)ICc"PII11I~

oUnfortunately therearealsoanumberofmaterials whicharefrequently KISUSiDasfireproofing systems.?'.aterials whicha'emisusedforoutdoor,fullyexposedenvironmental conditions include:2.3.StandardThermalInsulation Systems:Conventional, socalledstandardinsulation techniques, suchasmetallic-sheathcoveredcork,glass-wool, oraggregate systemssuchasvermiculite, perlite,orcalciteprovideexcellent heattransferprotection fortheflowing/stored media.However,suchsystemsarepoorfireproofing materials.

Eornallythethermalinsulation systemshaveverypoorbondingproperties tothebasestructure andareusuallycoveredwithathinmetallic-sheathing forprotection ofthethermalnsulation fromenvironmental effects.Underdirectflamecontact,and/orhighintensity radiative heatfluxes,thesethinmetalliccoverings willquicklyexperience largedeformations withanattendant lossofthermalprotection.

entrapped moisturebetweenthethermalinsulation andthesteelstruc-turecanprovideacorrosion problemaswellasgenerating sufficient steampressuretoactuallyblowlargesectionsoftheinsulation systemoffoftheprotected structure underhighheatfluxconditions.

Refractory Protection Systems:Yostrefractory materials provideexcellent hightemperature thermalprotection insuchapplications askilms,ovens,andhightemperature processlines.However,thesematerials areoftenmisapplied asfireproofing systemsforsteelstructures thatcouldbe-comeexposedto.flammable liquidspillfires.Hostflammable liquidsreachtheirmaximumburningintensity withinafewsecondsandimposeveryhighthermalgradients intheouterregionsoftherefractory protection systemsinashortexposureperiod.Underlargethermalgradients andtheresultant highthermalstresses, mostrefractory materials willcrackand/orspill,possiblyleavinglargestructural sectionsofthebasicstructure completely unprotected.

Ingeneral,therefractory materials aredesignedtobebroughtuptotheirnormaloperating temperature overanextendedtimeinterval, aswellasbeingcooleddownquiteslowly.Intumescent PaintCompounds:

Thesepaintingcompounds, whenunsubjected toflametemperatures, puff.upto,formanair-filledashwhichactslikeaninsulator material.

Unfortun-atelytheirabilitytointumesce islostaftershortperiodsofexposuretooutdoorenvironmental conditions, usuallylessthantwoyears.Averyseriousprobleminusingtheintumescent paintingcompounds forthefireproofing ofexposedstructural steelsthatcouldbesubjected tohighvelocityWESSONANDASSOCiATESO INC. flamesimpingement istheextremefragility oftheair-filledashformedbytheexposureoftheintumesc0nt painttohightemperatures.

Experimental datahaveclearlyshownthatthegasvalocities associated withClassIflarmable liquidsunderdirectflamecontactconditions aresufficient tocompletely destroy,ordislodge, theinsulating air-filled ashlayers'~>laterofHydration Plasters:

Thesecoatingsaresimplyplastercompositions whichundergochemicalandphysicalchangeswhenexposedtohightemperatures toreleaswatervapor.Thetheoryisthatthetemperatures oftheprotected structure willbelimitedtothetemperature ofhydration processandthatthefireenergyisabsorbedbythehydration processandinthevaporiz'ation ofthewatervaporproducedbythevariousreactions.

Thematerials thathavebeentestedandreporteduponintheliterature haveexhibited ahighdegreeofhydroscopicity andaverylimitedabilitytowith-standexposuretooutdoorenvironmental conditions forevenshortexposureperiods,lessthanoneyear.heinherentpossibility ofcorrosion duetothewatercontentofthesecoatingsisaseriousdrawbacktotheuseofthesematerials forfireprotection ofsteelstructures.

DISCUSSION OFEXPERIMENTAL DATATheprincipal sourcesofexperimental dataonthefireprotection capabilities ofthevarioustypesoffireproofing materials, otherthantheindividual companyresearchanddevelop-mentprogramswhich'arenotnormallyavailable tothegeneralpublic,aretechnical papersthathavebeenpresented atengine-eringconferences suchasthe1973AnnualHeetingoftheA.I.Ch.E.

inPhiladelphia, PA(1,2),theFireproofing andSafetySymposium oftheVestemResearchApplication CenterofLosAnge1es,CA,in1971(3),independent testingprogramssuchastheDepartment ofTransportation-Federal RailroadAdministration LPGtorchingtestsoncoatedplatesandfull-scale fireengulfment testson33,000galloncapacityLPGtankcarsfilledwithLPGin1974-75(4),andFactoryHutualResearchtestingreportsmadeavailable totheauthorbyasublimation compoundtypecoatingmanufacturer (5,6,7;8).

Alloftheseseparatesourcesofexperimental data.havebeenutilizedtoformaslarge.a.databaseasispossible'oritechnical evaluation oft&iethermalperformance character-isticsandcapabilities ofthevariousfireproofing coatings.

Unfortunately, most,ifnotall,theavailable experimental datahavebeenobtainedunderdirectflamecontactconditions and/orEVESSONhNDASSOCIATES, INC.

iS~(~e7underrelatively highpressureimpinging, ortorching, fireconditions, andassucharenotdirectlyapplicable tothoseconditions whereinonlyprotection from"radiantheatfluxes"isdisired,or-required.

However,duetotheverywidevari-ationofthetypesofhydrocarbon fuelsinthevariousdirectflamecontacttests,andtheresultant.

widevariation incoatingsurfaceincidentheatfluxes(fromalowof12,000BTU/HRSQ-FTtoahighof67,200BTU/HRSQ-FT),ithasbeenpossibletocorrelate theexperimental datainaformthatitcanbeusedfortheprediction oftherequiredcoatingthickness forvarioustypesoffireconditions rangingfromhighpressureflamesimpingement toonlyincidentradiative heatfluxconsiderations.

TableIpresentsalistingofthedifferent typesofhydro-carbonfuelsthathavebeenusedinthevariousreportedtestingprogramsandtheradiative, convective, andtotalheattransferratesreportedintheresearchliterature foreachtypeoffuel.Alistingoftheliterature sourcesfortheseheattransferratesisalsonotedonTableI.AslistedinTableI,theradiative heatfluxesrangefor5,000to39,000BTU/HRSQ-FTdepending onthefuelandfiresize,andtheconvective heat'fluxes rangefromabout7,000to11,000BTU/HRSQ-FT,depending onthe.firesize.Atabulation oftheexperimental datausedintheengine-eringanalysesandevaluations reportedhereinispresented inTableII.Asshown,experimental dataforasublimation compoundcoating,anintumescent masticcoating,acomposite systemcom-posedofaninsulating typeconcretewithanexteriorcoatingofanintumescent mastic,andanablativetypecoatinghave'been utilizedastypicalexamplesofthevariousfireproofing coatingsapplicable fortheprotection ofoutdoorstructural steelsandLPGstoragetanks.ThefuelsusedintheTableIIexperimental resultsincludemethanol, hexane,JP-4andLPG.Thevariouscoatingthicknesses rangedfrom0.125inchesto0.750inches.Thestructural steelsubstrates include5/8inchplate(LPGstoragetankshellmaterial) and8$~r31,8VF39and104%49steelbeams.Theexposuretimesfortheparticular steelsubstretes toreach300oF,500F,800Fand/or1000F,asapplicable, arealsogiven.Thesourcesoftheexperimental dataarealsolistedonTableII.DATAANALYSES:

STRUCTURAL STEELBEAMSInordertogeneralize theavailable directflamescontactandimpinging firetestdataanddevelopageneralized engineering datacorrelation thatcanbeus'edforanytypeoffireheatingcondition, theTableIIexperimental datahavetobeexpressed asLESSONhNDASSOCIhTES,

?NC.

~~ft~~-8-.TABLEITOTALRADIANTSUMMARYOFTOTALCONTACTHEATFLUXESFORVARIOUSTYPEHYDROCARBON FLAMESMAXIMUMHEATTRANSFERTOACOLDTARGET(BTU/HRSQ-FT)CONVECTIVE MethanolAcetoneHexaneCyclohexane JP-4:SmallFiresJP-4:LargeFiresBenzolLPG:Impinging TypeFiresLPG: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.,"SafeSeparation Distances fromLiquidFuelFires",FireTechnolo,1,47(1971).Law,M.,"Structural FireProtection intheProcessIndustry",

Buildin,86-90(18July1969).Nei,D.T.,Welker,J.M.,andSliepcevich, C.M.,"DirectContactHeatTransferfromBuoyantDiffusion Flames",J.Fire6Flammabilit 1,289(1970).Rasbash,D.J.,Rogowski, Z.E.,andStark,G.W.V.,"Properties ofFiresandLiquids",

Fuel,35,(1956).Bader,B.E.,"HeatTransferinLiquidHydrocarbon FuelFires",Proceedings, International Symposium forPackaging andTrans-portation of.Radioactive Materials, SandiaCorporation andU.S.AtomicEnergyCommission, SC-RR-65-98, Albuquerque, NM(12-15January1965).Anderson, C.,Townsend, W.,Markland, R.,andZook,J.,"Comparison ofVariousThermalSystemsfortheProtection ofRailCarsTestedattheFRA/BRLTorchingFacility",

BRLInterimMemorandum ReportNo.459(December 1975),FundedunderFederalRailroadAdministration, DCNAR30026/Req.

731231WESSONhNDASSOCEhTES, INC.

TAbLEIISUMMARYOfEXPERIMENTAL DATAONTHERMALPROTECTION SYSTEMEXPOSEDTODIRECTFLAMESCONTACTTYPEOffUELTYPEOFIOFCOATING.~INCIDENTHEAT'."INCHESOFCOATINGSUBSTRATE THICKNESS FLUX"PKRTHOUDANDS Ol'in)(BTU/HRSQFT)BTU/HRSQ-FTTIMEFOlLSUBSTRATE TOREACHSPECIPIEDTE%'ERATURE Minutes300of500F800f1~000SUBLIMITATION COMPOUNDuII~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>COMPOSITE SYSTEM".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"Comparison ofVariousThermalSystemsfortheProtection ofRailCarsTested~ttheFRA/BRLTorchingFacility",

BRLInterimMemorandum RcportNo.4S9(Decembet 1975)~FundedUndettheFederalRailroadAdmin~istration, DCNAR30026/Rcq.

7312312~Concerning FireProtective

Coatings, ASvmssryof~Symposium Presented attheA.I.Ch.E.MeetinginPhiladelphia, PA(November 1973)~3~Fcldmsn>R.,"FireRetardsncy andHeatTransferTransmission ControlUsingAppliedMaterials"

~Presented totheFireproofing andSafetySymposium, WesternResearchApplication Center,LosAngeles>CA(May1971)~4,O'Rourl,c, J.F~~"TheUseofIntumcscent CoatingsforFireprotection ofStructural Steel",Presented atthe.AnnualMeetingoftheAI~ChE>Philadelphia

>PA(November 1973)~5>TSI>INC.>Tcchnical NoteNo.75120>"Thermo-Lag Subliming SystemforExtendedFitcResistance ofLPCStotadeTanks"~Januar<197S~ theexposuretimerequiredtoreachapreselected temperature

-levelasafunctionofthecoatingthickness, incidentheatfluxandsubstrate heatcapacityforeachparticular typeof'coatihgandmetallicsubstrate.

Figure2presentsacorrelation oftheFiguredataforanintumescent coatingappliedtoavarietyofstructural beamssizes.Asshown,thetimerequired~forstructural steelbeamstoreachthedesignlimitingtempera-tureof1000Fcanbeexpressed asafunctionof(T)(W)'(F),where:0.5TFireproofing coatingthickness ininchesWWeightofthestructural steelbeamsinlbs/ftF=Totalincidentheatfluxinthousands ofBTU/hrsq-ftTheFigure2correlations haveconsderedafireproofing coatingthickness rangeof0.125inchesto0.500inches,structural beamsizesfrom8WF31to14WF228,andatotalincidentheatfluxof29,500BTU/hrsq-ftasbeingapplicable totheASTM-E-119 flamesexposuretestmethod.Thedifferent datacorrelations shownfortheintumescent

.masticcoatingsandthesublimation compoundcoatingsadequately illustrate theverysignificant effectofthecoatingthermalproperties onageneralized engineering correlation.

If,orwhen,sufficient dataonthe"energyabsorption rates"ofthevarioustypecoatingsbecomeavailable, itshouldbepossibletoexpresstheindividual datacorrelations asasinglegeneralized correlation ofthetype:afunctionof(T,AT,F,W,E)abcdewhere,tT=AT=FWFlamesexposuretimeFireproofing coatingthickness Temperature riseofstructural beamsubstrate TotalincidntheatfluxWeightofbeamperlinearfootexposedtoflamesheatingCoatingenergyabsorption rate.DATAANALYSES:

LPGSTORAGETANKSDuetothelargescaleengulfment firetestsandplatetorchingtestsconducted bytheDepartment of.ransportation-Federal Rail-roadAdministration onfullscale33,000galloncapacityLPGrail-carsfilledwithLPGproduct,andthepossibleapplication ofthesedataforfireproofing ofothertypeflammable productstoragetanks,particular attention hasbeengiventotheTableIIexperi-AVESSONANDASSOCIhTES, INC.

~IQlVO~s,p~r~~~'EGEND~..-.":"-'...

08WF31BeamsCoveredwithIntumescent Mastic(1)010WF49BeamsCoveredwithIntumescent Mastic(1)~14WF228BeamsCoveredwithIntumescent Mastic(1)O8WF39BeamsCoveredwithSubliming Compound(5)10WF49BeamsCoveredwithSubliming Compound(6)~,~~CTimeforBeamstoreach-."300F:Subliming Compound~.Coatings40~~~~eI~~(~:--:':::.-"--

'::.~~~~I20P~~~~I'I'I'~~~~A~t:I~~I~~~~~~~I~~~~~~II~~~~~~~~~~~~~I~~el~02'405'"lo.40.(T)(W)'FFIGURE2:CORRELATION OFTHETHERHALCKARACTERISTICS OFDIFFERENT TYPEFIREPROOF COATINGFORSTRUCTURAL STEELBEPJ'iS.2001Ie~.el~I~ill<<'.'I'.<~tw~I'-'T.~Fireproof coatingthickness inches-'.:-:'::'..!:.-':-

F~Incidentheatflux,thousands ofBTU/hrsq-ftWeightperfootoflengthforSteelBeams,1bs/ft00~<:.::TimeforBeamsto8:.:reach1000oF:Subliming "A---,-Coating,....I.'"."Timefor'eamstoreachi.'::-':-j:;.1000F:Intumescent 1the80OI60AC/1 mentaldatarelatingtothisDOT/FRAtestingprogram(4).~~~~~~~However,beforepresenting theresultsofthedata.analysesoftheDOT/FRALPGrailcartestprograms, itmaybeofinteresttonoteafewofthecharacteristics associated withLPGstoragetankfirehazards.Itisimportant torealizethatpastfireexperience showsthatwatercoolingofLPGtanksisnottotallyeffective fortheprotection ofsuchtankswhenthetanksareexposedtofullengulfment and/ortorchingfireconditions, especially whentheimpinging fireisontheLPGtankvaporspace.Itisequallyimportant torealizethatthenewlvdeveloped "passivefireproofing" cannotdelayLPGtankBLEVE(BoilingLiquidExpanding VaporEx-plosion)foranindefinite timeperiod.conomicconsiderations, aswellasdesignandsystemapplications considerations, dictatethatpractical tineexposurelimitsmustbeestablished forthese"passive",

orfireproofing, protection systems.Theseexposurelimitsareinfluenced bythefollowing considerations:

1.2.3.4.The"credible" amountoffuelavailable tobeburned.A"credible" rateoffuelreleaseifaspillfireisinvolved.

Typeoffirecondition(s) tobeconsidered.

Forexample,iXthedownwinddistanceofflammable vapor-air mixtureistobelimited,thentheLPGspillsurfaceareamustbecontrolled.

Thismayrequireimpounding ofthespilledLPGattheLPGtankarea,orcloseby,witharesultant possibility ofspillfireflamesimpingement, orhighintensity radiantheatfluxes,directlyupontheLPGtank.Theavailability and/orresponsetimeforemergency counter-actionssuchasmanualshut-offofflowcontrolvalves,timeforsettingupremotecoolingwatermonitors, timeforlocalFireDepartments torespond,etc.ThefailureofanLPGtankexposedtoafiresituation isdirectlyrelatedtothetank'ssteelstructural strengthchar-acteristics asafunctionoftankshelltemperature.

Ingeneral,thestrengthofLPGtanksteelmaterials increases asthesteel0temperature increases toatemperature rangeoffrom600to800F.Somewhere intherangeof650to850F,depending ontheparticular.

steelbeingconsidered, thestrengthstartstodecrease.

Atasteeltemperature ofabout1000F,theburststrengthofanLPGtankwillbereducedtoabout300psiginternaltankpressure.

'Atabout1100F,theburststrengthcan'b'easlowas.200p'sig.Thus,prolonged exposuretofireheatingconditions canreducetheburstpressurecapabilities ofanLPGtankfromthenormalrangeofaboutlOCOto1250psigatanbienttemperature conditions to200psig,orlower,duringafiresituation.

Then,depending ontheexposuretine,thesteeltemperature, thereliefvalvesetting'and capacities, andtheamountofLPGinthetank,aBLEVEcondition couldresult.WESSONhNDASSOCIATES, INC.

~~-13-Th'eenergystoredinanLPGtank,oranypressurevesselforthatmatter,duetointernalpressurization isproportional

'-tothevolumeavailable forproductvaporsandtheamountof.:energyavailable forreleaseperunittime.Agenerally acceptedmethodforcalculation ofthenetamountofenergyavailable istoequatethereliefvalvesetpressuretoacalculated equivalent o8TNTpercubicfootoftankvolume.Thiscanbedoneusingtherelationship:

FLbsofTNT=0.00135VPPPln-Pawhere,VVolumeofLPGtank,cubicfeetP=LPGtankpressurereliefvalvesetpoint,psiaPAmbientpressure, psia.Theval'uethusderived'foraparticular tank'sTNTequivalent isusefulinestimating theover-pressures resulting fromaBLEVEcondition.

Thedamagepotential ofaTNTexplosion asafunctionoftheseparation distancefromtheexplosion sourcepointcanbeestimated fromthemaximumoverpressure atthepointofinterest.

Assumingacylindrical chargeofTNT,themaximumoverpressure canbeestimated fromtherelationship, Pm=Po11.34185.9Z219210Z3.where,P=maximumoverpressure, psiP=Ambientpressure, psiaZ~3.967R/(TJ)RDistancefromexplosion source,feeth'TNTequivalent weight,lbs.Theassumption ofacylindrical chargeofTNTinEquation2givesaconservative valuefortheoverpressures ascomparedtothoseforarectangular chargeofTNT.However,thenormalconfiguration ofanLPGstoragetankdictatestheuseofthecylindrical shapecharge.~Thevariation'f maximumoverpressure

.withdistanceforseveralTNTequivalent weightshasbeengenerated fromtheEquation2andtheseresultsarepresented inFigure3.Across-plot ofFigure3ispresented inFigure4andissomewhatmoreconvenient tousefortheestimation ofthedamagepotential duetoanLPGtankBLEVE.Forreference

purposes, themaximumoverpressure froma250psigLPGtankBLEVEcondition isindicated LESSONhNDASSOCIhTES~

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!da a~e-'Xxa~~lI~me.l&.concrete

~It.'oitIpood3Qock-'-~II~~i'~I!I~~I~I.er-:.+.a ss-.window III-~i'i~~.--~-'-':~ll~~~~~~~~~~~~~~~~)it-,~~I<<Cncl~VIVIrnIVOlioteVI<<WCIIISaVI/dODistancefromExplosion Source,feetFIGURE3:DPJ'!AGEPOTENTIAL'S FRO~!TNTEXPLOSIONS

~~~~~~0g%g!ssaaraPwal I%%ll5,$88%5'WSII,~d~kgHIIM~SE ggli~%%gSEHS~MlgWISltllllWgH~~INISMIIW~INIMWWRRsaaalMN~~WW gggplFglSICIllBlBRII1W~FiI'l)IIIII'I8,goal~tglill-~s~.i.htIIIII~0 onFigure4.ItshouldbenotedthattheFigure4damage"potentials donotaccountfor"projectile" damagethatmightresultfromanLPGtankBLEVEcondition.

Thereare,numerousexamplesintheliterature ofthecon-sequences ofLPGtankfiresandBLEVEconditions.

However,themostcommonandfrequentcauseofmajortankfailuresappearstobefromsafetyreliefflarefiresburningforprolonged periodsoftimeabovethetank'svaporspaceand/orimpingement onthevaporspaceofadjacenttankage.Areviewoftheliterature, available testreportsandpublished articlesindicatethefollowing facts:l.Mostengulfment firesexhaustthetankcontentswithinonehouroffireexposure.

2.Thermalcoatingsthatareapprovedbynationally recognized andindependent testingand/orfireratingagenciesare~available forfireratingunderdirectflamescontactcon-ditionsforinexcessofatwo-hourexposureperiod.3.AgoodmediumresponsetimeforaCityFireDepartment andset-upforapplication ofcoolingwaterforLPGstoragetanksisabout15to20minutes.4.ThemediumtimetoBLEVEforanunprotected tankisabout14minutes(somewhat lessthanthemediumresponsetimefortheCityFireDepartment).

5.Safetyreliefvalvefirescanbeextinguished bycoolingof:thetankcontentstobelowthatpressurelevelatwhichthesafetyreliefvalvewillopen.6.Noneoftheconventional standardinsulation systemsnowavailable willwithstand alldesignrequirementg andkeeptheLPGtankvaporspacetemperature below120Ftemperature isaboutthatfor250/225psigreliefvalvesetting.7.Excessflowvalvescannotbedependeduponalonetostoptheflowoffuelduetopossiblerestrictions inthesupplylinesandleakrateswellbelowthatnecessary forexcess.flowvalveoperation.

8'.A"passive" thermalprotection system(asystemthatdoesnotrequiretheactuation ofprotective equipment ormanpowerresponse) isjustasimportant atankdesignfeatureasthesafetyreliefvalve.-LESSONhNDASSOCIhTES, INC.

9.A"passive" thermalcoatingthataffordsatleastone-hourofprotection shouldbeappliedtoallLPGtankagetoallowfirementoinitiateapplication ofsupplemental coolingwater.10.Automatic fire,orheatactuated, valvesarecommercially available

'andarehighlyreliable.

Suchvalvesshouldbeinstalled inallliquidtransferlinesandshouldbeofthefullinternaltype.AsaresultofthelargenumberofLPGtankfiresand/orBLEVE'sthathaveoccurredandarestilloccurring inthiscountry,andperhapsdueinparttosomeidentification ofthetypesoffiresthatcausesuchincidents, theDOT/FRAsponsored aresearchandfullscalefiretestingprogramonfullsize,andfilled,33,000galloncapacityLPGrailroadtankcars.Thistestingincludedenvironmental tests,one-fifth scalepreliminary firetests,fullscalespillfreengulfment testson33,000gallontankcars,andhighpressureflameimpinging (torching) firetestsonsamplesizeLPGtankmaterialplatesprotected withmost,ifnotallavailable, thermalprotection systems.Someoftheprotection systemsfailedduringenvironmental tests,othersfailedduringtheone-fifth scaletests,andotherssuccessfully completed alltherequiredtests.SincethehighpressureLPGimpinging firetestsr'esulted inthemostsevere,butrealistic andpossible, fireheatingrates(upto67,200BTU/hrsq-ftincidentheatfluxes),coatingerosionconditions, andcoatingthermalstressratesandlevels,theremainder ofthispaperwillbedevotedtothegeneralanalysisofthetwohighestperformance levelsystemsresulting fromtheDOT/FRA~(4)experimental testingprograms, anablativetypecoatingandasublimation compoundcoating.Fromtheformeran'alyses discussed forstructural steelbeams,itappearedthatthedataobtainedfromthesampleplatetorchingtestsshouldcorrelate intheformof,t=afunctionof(T,F,BT,M)abc,dwhere,t=Plateexposuretime,minutes'T=Thermalcoatingthickness, inches04T=Steelplatesubstrate temperature rise,FFITotalincidentheatflux,thousands ofBTU/hrsq-ftW=Steelplateweightperunitareaexposedtoflamesheating,lb's/sq-ft a,b,c,d=Correlating coefficients.

Figure5presentsthecorrelating resultsfortheablativecoatingandthesublimation compoundcoatingexperimental resultsobtainedfromtheDOT/FRAtorchingtestson5/8"thicksteelplatesamplesLESSONhNDASSOClATES)

INC.

JS.LEGEND'TIMEFOR5/8"PLATETOREACH800F":8TDKFOR5/8"PLATETOREACH500OF&TINEFOR5/8"PLATETOREACH300FOPENPOINTS,SUBLDfATION COaiPOUND COATING~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/THOUSANDS OFBTU/HRSQ-FTINCIDENTHEATFLUX7FIGURE5:CORRELATION OFDOT/FRALPGTORCHINGTESTSRESULTSON5/8"THICKLPGTAhKPLATEl'fATERIAL intheformofplateexposuretimeexpressed asafunctionofthe'oatingthickness dividedbythetotalincidentheat,fluxwighthemetalplatesubstrate temperatures of300,500,and800F.'sacorrelating parameter.

ThefivetestpointsshowninTableIIforthesubt.imation compoundtypecoatingresultedinanex-cellentlinearcorrelation fortheFigure5log-logtypeofpresentation.

Thetwoexperimental testpoints(ateachofthethreenotedplatetemperatures) fortheablativetypecoatingshowninTableIIandtherelativelocations withrespecttothesublimation compoundcoatingcorrelations foreachtemper-ature,indicatealinearcorrelation fortheablativetypecoatingthathasthesameslopeasthatofthesublimation com-poundtypecoating'.

Youmightrecallthatthischaracteristic wasnottrueforacomparison ofthesublimation compoundcoatingandtheintumescent masticcoatingsforsteelstructural beams,whereintheslopeswerequitedifferent.

Acloseexamination oftheFigure5datacorrelations indicates twoimportant features; one,theparallelism ofthelinearlines.shownforthe300,500,and800oFplatetemperatures indicated thatitshouldbepossibletocollapsethethreelinestoasinglelinecorrelation incorporating platetemperature riseasageneralcorrelating parameter and,two,thesublimation compoundcoating,takingagivenplatetemperature riseatagivenperiodofexposure, hasahigherthermalperformance capability thandoestheablativecoating,usingtherequiredcoatingthickness asameasureofthecoatingthermalperformance capabilities.

Forexample,foratwo-hourexposureatanincidentheatfluxof30,000BTU/hrsq-ft(thisheatfluxcouldcomefromanytypeoffiresituation:

directflamescontact,flamesimpingement underpressure, oronlyrad-iativeheatloads)andalimitingplatesubstrate temperature of800oF,thesublimation.

compoundcoatingrequiresonly66/.ofthethickness requiredbytheablativecoating(0.180inchesversus0.273inches).Ifwemakeanassumption similartothatutilizedfortheFigure2generalcorrelation forstructural steelbeamswhereinitisassumedthatthemetalsubstrate heatcapacitycanbecorrelated asthebeamweightperlinearfoot,itshouldbepossibletoobtainacompletely generalized correlation forthesublimation compoundcoati-.gwhenappliedtometalplatesubstrates.

AsisshomxbyFigure6,suchacorrelation ispossible, andcorrelates alltheTable.II'test datafor5/8".thick steelplatequitewell.Asshown,theexposuretimecanbeexpressed asageneralfunctionofthesublimation compoundccatingthickness timesthosubstrate te-...perature risetoanexponentof0.70,timesthemetalplatesubstrate weightinlbspersq-ftofexposedsurfaceareatoan0.50exponentdividedbythetotalincidentheatfluxinthousands ofBTU/hrsq-ft.Thus,theFigure6LESSONANDASSOCLAYES%

INC.

loto~-20-~~I~~I'I~~~~~II00,~,Ir0TEST~-.-OTEST~':..'.4TESTI'~~~I~~~~.~.~.o~0~~~~)~~POINTSFOR300FMETALSUBSTRATE POIXi'TSFOR500F~iiETALSUBSTRATE POINTSFOR800FiiIETALSUBSTRATE

~~~~~~~~~~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, inchesTemperature RiseofMetalSubstrate, OFXncident.Heat Flux,Thousands ofBTU/HRSQ-FTWeightofMetalSubstrate Plate,abs/sq-ft ofplatesurfaceareaexposedtoheatflux~I~,l~~~~1~I~)~~~~2o~~~~I~o~~~~~~~~~0.5j(F)~t~~o~o0.11.01020XGURE6:GENERALIZED CORRELATION FORTHETHERK%LEFFECTIVENESS OFTIIESUBLI1ITATIONCO.PO&i'D COATINGAPPLIEDTOASUBSTRATE OFCARBON.STEELPIXTE~~o~~~~;.o~~IiI correlation canbeusedforengineering designpurposesforthedetermination oftherequiredsublimation compoundcoatingthick-nessforanygivenfiresituation, givenmetalplatesubstrate "thickness',

andspecified allowable substrate temperature.

Theparallelism oftheFigure5correlations forthesub-limationcompoundcoatingandtheablativecoatingalsosuggeststhataparameter expressing the"energyabsorption rate"ofthetwotypecoatingcouldbeusedtomaketheFigure6generalized

'orrelation applicable for.bothtypecoating.However,thishasnotbeendoneasyetduetoalackofknowledge ontheexactenergyabsorption characteristics ofthetwocoatings, butcanbedoneoncethischaracteristic isdefined.Toillustrate thepotential usagefortheFigure6datacorrelation, letusassumethatwewishtothermally protecttheroofofaparticular productstoragetankfromthethermalradiation dueofanadjoining tankfiresituation foraperiodofone-hour.

Typicalnumbersapplicable tosuchasituation

.wouldbeasfollows:l.Incidentradiantheatflux:12,500BTU/hrsq-ft2.Roofthickness:

0.250inchesofcarbonsteelplate(10.2lbs/sq-ft) 3.Designallowable rooftemperature:

350F(70Fambient)4.Protectwithsublimation compound.

coating.FromFigure6at60-minutes ElapsedExposureTime,wereadafigureof2.0.Thus,or2.0~(T)(4T)(W)'(F)T=2.0(12.5)/(280)

'10.2)T~0.152inchesofsublimation compoundcoating.Basedonthepreceeding discussions andengineering datacorrelations, itcanbeconcluded thatLPGtankagecanbethermally protected witha"passive" fireproofing coatingsystemthatexhibits'he following performance capabilities:

l.The'assiv'e thermalcoatingmustkeeptheLPGtanksteeltemp-.eraturetobelow800oF,foraperiodof..two-hours when;,the tankisnotmorethan807.fullofliquidproduct,andthetankis'exposed todirectflamesimpingement fromaspillfirebelowtheLPGtankhavingthefollowing characteristics:

a.Incidentheatfluxoffrom40,000to50,000BTU/hrsq-ftWESSONhNDASSOCIATES, INC.

~~j-22-b.Flamevelocityontheorderof100ft/sec-"--"-c.DistancefromspillsurfacetoLPGtankbottomis3-ftorless.2.Thethermalprotective coatingshouldbedurableintheintendedexposedenvironmental serviceconditions foraperiodof20years,withthetopcoatrenewalbeingatleastfivetosevenyears.Duringthisserviceperioditshouldnotdust,flake,chip,crack,orspalloffduringnormalserviceconditions.

3.4.Duringfireconditions, theresidualcoatingshouldnotspallfromthethermalshockduetosupplemental waterstreamcooling.Thethermalcoatingmaterials shouldbenon-toxic andentirelynon-flammable.

5.6.Thematerialshouldnotcontainanyasbestos.

Thematerialshouldnotbecorrosive tostructural steels.7.9.10.Thematerials shouldberesistant tochemicalspillsandfumesfromthosechemicals normallyassociated withpetro-leumandpetrochemical processing andstorageplants.Thematerials shouldbeapplicable withairlesssprayequip-mentandthecoatingshouldcurewithinamaximumtimeperiodofthreedays,at75oFand50%relativehumidity.

Thematerialshouldhaveabondingstrengthofnotlessthan100psi.Whenusedforprotection oflowtemperature flammable liquidstorageortransferlinesl,'suchasLPGorLNG),submergence and/orliquidspraycontactwiththestoredproductshouldnotresultinanyadverseconsequences onthefireproofing capabilities ofthecoating.Further,thecoatingshouldbeabletowithstand simultaneous exposuretothelowtemp-eratureliquidsanddirectflamescontactconditions withoutlossofprotective capabilities.

CONCLUSIONS Easedupontheexperimental data,dataanalyses, anddis-cussionspresented herein,itcanbeconcluded that:Itispossibletogeneralize theexperimental dataobtainedfromspecificratingtestsonspecified structural substrates withspecified coatingthicknesses exposedtodirectflameWVEssoNAM)AssocIhTEsi INc.

contactfireconditions intogeneralized engineering cor-----'elations foreachtypeofsteelsubstrate andcoatingwhichexpresstheprotection timeasadirectfunctionofthe....-':-"'coating thickness, substrate temperature rise,substrate heatcapacity, andtotalincidentheatfluxes.Theseengineering correlations canthenbeusedforthedetermin-ationoftherequiredtypeofcoatingthickness foragivensubstrate, givensubstrate designtemperature andgivensub-strateheatcapacityunderanytypeoffireheatingcondition (flamecontact,impinging flames,and/orflamesradiation).

Basedontheexperimental datapresented in'thispaper,andnowavailable intheresearchliterature, thesublimation'ompound typecoatinggivesasuperiorfireproofing performance, asmeasuredbythethickness ofcoatingrequiredwithallotherapplicable parameters heldconstant, thananyotherfireproofing coatinganalyzedinthispaper.REFERENCES 4.8.2.O'ourke,J.F.,"TheUseofIntumescent CoatingsforFireProtection ofStructural Steel",Presented atthe1973AnnualMeetingoftheA.I.Ch.E.

inPhiladelphia, PA(November 14,1973).Kayser,J.N.,"TestsofFireproofing Materials forStructural SteelforRefineries andChemicalPlants",Presented atthe.1973AnnualMeetingoftheA.I.Ch.E.

inPhiladelphia, PA(November 14,1973).Feldman,R.,"FireRetardancy andHeatTransmission ControlUsingAppliedMaterials",

Presented totheFireproofing andSafetySymposium,

>lesternResearchApplication Center,LowAngeles,CA(May27,1971).Ballistic ResearchLaboratories, AberdeenProvingGround,YD(Anderson, C.,Townsend, V.,Markland, R.,andZook,J.),"Comparison ofVariousThermalSystemsfortheProtection ofRailcarsTestedattheFRA/BRLTorchingFacility",

InterimReportNo.459totheDepartment ofTransportation, FederalRailroadAdministration, Uashington, DC{December 1975).FactoryMutualResearch, "FireEndurance TestonSteelColumnsProtected withThermo-Lag 330-1Coating",

ReporttoTSI,Inc.,St.Louis,MO(November 6,1972).FactoryMutualResearch, "ASTME119FireEndurance Test(Modified)

Structural'Steel ColureProtected byThermo-Lag 330-1Coa'ting-DesignCT-36",ReporttoTSI,Inc.,St.Louis,MO(April1974).FactoryMutualResearch, "Exploratory FireEndurance FireTestonStructural SteelColumnwithThermo-Lag 330-1Coating".

ReporttoTSI,Inc.,St.Louis,YO(November 30,1973).FactoryMutualResearch, "Exploratory FireEndurance TestonStructural SteelColumnwithThermo-Lag 330-1Coating",

ReporttoTSI,Inc.,St.Louis,MO(November 30,1973).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"-naoroHDDIPf IKt625'-IoIii8)2C'ARgXqSTALZe(IWAIIHOLg5ONKRAc>wslX)QSE.CTlo(46-I:.lilt1BCSPLlkRl.~F-FIPazotlE 4-ll8LTIPIRE~Kg-llNI'IRPEVALL5-4 SIZE(WIDTH)III'EDVINYLGRIP'2SINGLELEAFSTEELDIAMONDPATTERNPLATEReinforced for150lbs.persquarefootliveload.JJKIJ0II-6ZIJJIJNA.III'FLUSHLIFTHANDLEISTEELSTRAPANCHORIIIIIIIYES"DIAMONDPLATECOVERIIIIId~J'sGrII'I(IIIIIIItujIRCOVINYLGRIPA.AUTOMATIC NOLO.OPENARMIIIORSION/BARSHINOCTORSI~BARSSTAINLESS STEEL4--)SLAMLOCKWITHU---BRASSHANDLEaIIGeneralContractor, PleaseNote:Becarefulnottorackortwistframe~e~settingunit.Blockupandshimtheframeifnecessary tobesuredoorrestsevenlyonframeallaround.FaCtOQFiniSh:Steel-redoxideprimerHardware-cadmiumplatedsteelPLAN.VIEWSECTIONB-B(CoverinOpenPosition)

Manufacturers ofDoorsforSpecialServicesP~THEBILCOCOMPANYHcwHaven,Connecticut 06505NREMOVABLE KEYWRENCHI/4"STEELDIAMONDPLATECOVER0-<SLAMLOCKGII~SIZE(WIDTH)HNGEMASONRYOPENINGFQl/4"XS"XS" STEELANGLEFRAMEfIIEltilTlTGRSIGN5g7i5ilITggQiiST:iI'2.8IJ-alilt'TEEL g53.ilialTiANCHORaeftuufTITT ARCH'T.ORENG'RHFEIIITIILEICTIQl2'4"x2'4" Q22'4"x2W'galx3J+I3'4"x3'4"KHlH6650HaOOP&l~<4BLED,AlAW~~s~%aERARThisdrawingisthepropertyofTheBilcoCompanyandincorporates specifications andpatenteddesignsinwhichTheBilcoCompanyhasproprietary rightsand,accordingly, isnottobcreproduced withouttheexpresswrittenconsentofTheBilcoCompany.PURCHASEORDERPROJECTGEN'L.CONTRACTOR PURCHASER BILCOREPRESEHTATIV DWG.NO.ATEDATE i)'L~};p%S

+plCANELfciAMERICANELECTRICPO'WERSERVICECORPORATION OHERSystswMay15,1984suszEcTiD.C.CookNuclearPlantFireRatedFloorHatchesRFC's01-2676and02-2692V.DelFaveroF.S.VanPeltgJI.InresponsetoItem4,"Provideanyalternatives totheinsulation orcompensatory measuresthatmaybeavailable",

oftheNRClettertoMr.DolandatedApril4,1984,thefollowing measureswereconsidered:

Provideaverticalfireratedenclosure abovethehatch.Thisisnotpossibleduetothelimitedspaceandcloseproximity ofelectrical cabinetswhichrequireaccessformaintenance andoperation.

2.3~Layingafireratedblanketabovedoor.Thisimpedestheoperation ofthehatch,andcreatesapersonnel safetyproblem.Provideaverticalfireratedenclosure belowhatch.Thisisnotpossibleduetomanyinterferences withcables,conduit,troughs,andcabinets.

4~5.Addahorizontal fireratedpanelbelowhatch.Thereisaninterference withtheaccessladderandapersonnel safetyproblemofaccesstothehatch.Replacehatchwithafireratedhatch.Noprefabricated fireratedfloorhatchisavailable.

Wehavecontacted TheBilcoCompanyaboutdesignandtestingofafireratedfloorhatch.(See.attachedcommunications)

V.DelFaveroVDF:bcc::STFoxWQ<~~useaCVCVraa AMERICANELECTRICPOWERServiceCorporation AEP1Riverside Plaza$614)223-1000P.O.Box16631Columbus, Ohio43216-6631 March131984RobertLyons,President TheBilcoCompanyP0Box1203NewHaven,Connecticut 06505RE:D.C.CookNuclearPlantbc=0-4aeo

DearMr.Lyons:

Inarecenttelephone conversation youmayrecallourrequestthatTheBilcoCompanysubmitaquotation forfurnishing a2'-6"x3'-0"floorhatchbearinganUnderwriters "A"label.Itisunderstood thatyoudonotmanufacture aU.L.ratedfloorhatch,however,asAEPanticipates thelikelihood thatretro-fittingofseveralBilcoinstallations inthesubjectplantmayberequired, weneedtomakeallowance forsuchacontingency.

Ifthisrequestisagreeable toyoumaywesuggestthatyourquotation alsoincludethecostofonesubmission toU.L.fortestingandlabelingandaseparatepriceforeachsuccessive U.L.application asmaybenecessary.

Atafuturedate,ifAEPbecomescommitted tothereplacement ofhatchesasreferredtoabove,theprogramwillprobablybeindustrywideandtheseratedhatcheswillbeindemand.Asalongstandingpurchaser ofmanyofyourproducts, wehopethatyouwillbeabletofurnishuswiththedesiredpricingdata.Ifyourequireanyfurtherinformation, pleasedon'thesitatetocontactus.Yourearlyresponsewill"begreatlyappreciated.

Verytrulyyours,A.C.MacksoudChiefArchitect ACM:b THEBILCOCOMPANYP.O.BOX1203NEWHAVEN,CT065O5March21~1984Mr.h.C.MacksoudChiefArchitect AmericanElectricPowerServiceCorporation 1Riveraide PlazaP~0~Box16631Columbus, Ohio43216%631 RE:D.C~CookNuclearPlanttg-0-4200A

DearMr~Macksoud:

ThankyouforyourletterofMarch13,1984concerning yourrequire-mentsforafloordoortocarryanUnderwriters "A"label.'Rehavecontacted bothUnderwriters Laboratories andFactoryMutualEngineering DivisionwithrequestsforcoststofiretestoneofoursingleleafJ-3doors,size2'6"x3'0",andalsooneofourJ<<4doors,size5'0"x5'0",indoubleleafdesign.JustassoonasIreceivesomeinformation fromthemIhopeIwillbebetterabletoansweryourletterandIwillbeintouchwithyouatthattimeYourstruly,THEM.ANY\ipRobert:QonRJL:wfgRECEfVFDMAR231984ArcRtechu.d S~tt~'lANI ANDMAIHOCFCc07wasecacvaccgwc'avcurnklklcl'TilIITIhh'IQ'1e%t'1 eI:*4