nfpa 85 - شرکت همیار انرژیhamyarenergy.com/static/fckimages/files/nfpa/hamyar energy...

CopyrightNFPA

NFPA85BoilerandCombustionSystemsHazardsCode

2007Edition

Copyright2007NationalFireProtectionAssociation.AllRightsReserved.

ThiseditionofNFPA85,BoilerandCombustionSystemsHazardsCode,waspreparedbytheTechnicalCommitteesonFluidizedBedBoilers,FundamentalsofCombustionSystemsHazards,HeatRecoverySteamGeneratorsandOtherCombustionTurbineExhaustSystems,MultipleBurnerBoilers,PulverizedFuelSystems,SingleBurnerBoilers,andStokerOperationsandreleasedbytheTechnicalCorrelatingCommitteeonBoilerCombustionSystemHazards.ItwasissuedbytheStandardsCouncilonDecember1,2006,withaneffectivedateofDecember20,2006,andsupersedesallpreviouseditions.

ThiseditionofNFPA85wasapprovedasanAmericanNationalStandardonDecember20,2006.

OriginandDevelopmentofNFPA85

NFPA85hashadalonghistoryofdocumentsthathavebeencreatedandcombinedtoformthepresentdayNFPA85.(SeeAnnexM,OriginandDevelopmentofNFPA85,BoilerandCombustionSystemsHazardsCode,whichisaflowchartdepictingthecomplexdevelopmentovertheyears.)ThefirstofthesedocumentswasNBFU60,RegulationsoftheNationalBoardofFireUnderwritersfortheInstallationofPulverizedFuelSystemsasRecommendedbytheNationalFireProtectionAssociationfrom1924thatchangedfrom anNBFU/NFPAdocumenttoanNFPAcodein1946.

The2001editionofNFPA85wasacompilationofthefollowingsixstandards:

NFPA8501,StandardforSingleBurnerBoilerOperation

NFPA8502,StandardforthePreventionofFurnaceExplosions/ImplosionsinMultipleBurnerBoilers

NFPA8503,StandardforPulverizedFuelSystems

NFPA8504,StandardonAtmosphericFluidizedBedBoilerOperation

NFPA8505,StandardforStokerOperation

NFPA8506,StandardonHeatRecoverySteamGeneratorSystems

Inthe2001edition,significantnewmaterialwasaddedformultipleburnerboilers,including

CopyrightNFPA

requirementsforreburnsystems.Forheatrecoverysteamgenerators,theminimumpurgeflowrequirementspriortostartingthecombustionturbinewerereduced.

The2004editionwasorganizedtoprovideadministrativerequirementsinChapters1,2,and3andcommonrequirementsinChapter4,FundamentalsofBoilerCombustionSystems.Subsequentchapterscoveredthespecificrequirementsforeachoftheboilerandcombustionsystemscoveredbythisdocument.The2004editionalsoprovidednewrequirementsthataddressedselectivecatalyticreduction(SCR)systemsformultipleburnerboilers.

Inthe2001edition,AnnexMwasaddedtoassistuserstobetterunderstandthecomplexdevelopmentofwhatisnowknownasNFPA85.

The2007editionincludesthefollowingmajorchanges,bychapter:

Chapter4:

(1) ThespecificrequirementsforfurnacestructuraldesignhavebeenremovedfromChapter4andrelocatedasappropriatetotheindividualchapters.

(2) Requirementsforfluegaspathauxiliarysystemshavebeenaddedalongwithsupportingannexmaterial.

(3) ThesectionpreviouslytitledProgrammableLogicControllerswasmergedintothedesignrequirementsforthelogicsystem.

(4) Newflameprovingrequirementshavebeenadded.

(5) Commissioningandinstallationrequirementshavebeenconsolidatedintoasinglesection.

Chapter5:Theuseofvalveprovingsystemsinfuelgastrainshasbeenadded.

Chapter6:

(1) ThescopeofChapter6hasbeenclarifiedasapplyingfromtheforceddraftfaninletstothestackinlet.

(2) Requirementsforfluegaspathauxiliarysystemsspecifictomultipleburnerboilershavebeenadded.

(3) Purgerequirementshavebeenrewrittenandconsolidated.

(4) Furnacestructuraldesignrequirementsformultipleburnerboilershavebeenaddedandnowincludetheimpactofboosterfans.Implosionprotectionhasbeenclarifiedasnotbeingrequiredonunitsthathavenofaninthefluegasstreamdownstreamoftheboiler.Inconjunctionwiththesechanges,adefinitionof boosterfanhasbeenaddedtoChapter3.

(5) Requirementsforfuelgasandfueloilsafetyshutoffvalveswereadded.

(6) Sections6.6,6.7,and6.8havebeenmodifiedforconsistencyinnumberingandcontent.

Chapter7:

CopyrightNFPA

(1) Requirementsforlanceandburnersafetyshutoffvalveshavebeenadded.

(2) Requirementsforfluegaspathauxiliarysystemshavebeenadded.

Chapter8:

(1) ThescopeofChapter8hasbeenexpandedfromheatrecoverysteamgeneratorstoincludeothercombustionturbineexhaustsystemsthatpresentsimilarfireandexplosionhazards,includingthosewithnoheatrecovery.Adefinitionof combustionturbineexhaustsystemshasbeenaddedtoChapter3,andotherchangesweremadethroughoutthecodeasrequiredforconsistency.

(2) Additionalcombustionturbineinterlockshavebeenaddedtoensurefuelgasinleakageisnotoccurringduringthecombustionturbinepurgeandthatexcessivefuelisnotbeingintroducedduringcombustionturbinelightoff.

(3) Specificrequirementsforheatrecoverysteamgenerator(HRSG)implosionprotectionhavebeenadded.

Chapter9:ThefuelstowhichChapter9applieshavebeenrevised.

Chapter10:Transientdesignpressurerequirementsspecifictostokershavebeenadded.

TechnicalCorrelatingCommitteeonBoilerCombustionSystemHazards(BCSAAC)

MichaelC.Polagye, ChairFMGlobal,MA[I]

BillBass, ForneyCorporation,TX[M]

JamesR.Bostick, ABBAutomation,OH[M]

DaleE.Dressel, SolutiaIncorporated,MO[U]

DavidS.Eason, DetroitEdisonCompany,MI[U]

RonaldE.Fringeli, MarshUSAIncorporated,OH[I]

GordonG.Gaetke, TheDowChemicalCompany,TX[U]

MasaakiKinoshita, MitsubishiHeavyIndustriesLimited,Japan[M]

RobertMalanga, FireandRiskEngineering,NJ[SE]

JerryJ.Moskal, ALSTOMPowerIncorporated,CT[M]

NancyC.Polosky, Babcock&WilcoxCompany,OH[M]

PeterJ.Willse, GEInsuranceSolutions,CT[I]

CopyrightNFPA

HenryK.Wong, WashingtonGroupInternational,NJ[SE]

Alternates

RonaldJ.Fleming, ABBIncorporated,OH[M](Alt.toJ.R.Bostick)

RichardL.Haman, DTEEnergy/DetroitEdisonCompany,MI[U](Alt.toD.S.Eason)

Takayoshi(Ted)Isoda, MitsubishiPowerSystems,Incorporated,CA[M](Alt.toM.Kinoshita)

GeraldE.McCullion, Honeywell,Incorporated,GA[M](VotingAlt.toHoneywellRep.)

MichaelR.Mulherin, TheDowChemicalCompany,TX[U](Alt.toG.G.Gaetke)

JohnP.O'Rourke, ALSTOMPowerIncorporated,CT[M](Alt.toJ.J.Moskal)

CelsoG.Schmidt, ForneyCorporation,TX[M](Alt.toB.Bass)

Nonvoting

JohnC.deRuyter, TheDuPontCompany,Incorporated,DE[U]Rep.TConStokerOperations

MichaelB.Doherty, AmericanElectricPowerServiceCorporation,OH[U]Rep.TConPulverizedFuelSystems

JohnJ.Eibl, TheDuPontCompany,Incorporated,TN[U]Rep.TConSingleBurnerBoilers

DaleP.Evely, SouthernCompanyServices,Incorporated,AL[U]Rep.TConFundamentalsofCombustionSystemsHazards

BrianW.Moore, HartfordSteamBoilerInspection&InsuranceCompany,CT[I]Rep.TConFluidizedBedBoilers

JohnVanName, WashingtonGroupInternational,NY[SE]Rep.TConHeatRecoverySteamGenerators

HaroldR.Yates, HRY,Inc.,MI[SE]

CopyrightNFPA

Rep.TConMultipleBurnerBoilers

AmyB.Spencer, NFPAStaffLiaison

ThislistrepresentsthemembershipatthetimetheCommitteewasballotedonthefinaltextofthisedition.Sincethattime,changesinthemembershipmayhaveoccurred.Akeytoclassificationsisfoundatthebackofthedocument.

NOTE:MembershiponacommitteeshallnotinandofitselfconstituteanendorsementoftheAssociationoranydocumentdevelopedbythecommitteeonwhichthememberserves.

CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentsonthereductionofcombustionsystemhazardsinsingleandmultipleburnerboilerswithaheatinputrateof12,500,000Btu/hrandabove.Thisincludesallfuels.ThisCommitteealsoisresponsiblefordocumentsonthereductionofhazardsinpulverizedfuelsystems,fluidizedbedboilers,heatrecoverysteamgeneratorsandothercombustionturbineexhaustsystems,andstokerfiredboilers,atanyheatinputrate.

TechnicalCommitteeonFluidizedBedBoilers(BCSFBB)(Chapter7,andAnnexesHandL)

BrianW.Moore, ChairHartfordSteamBoilerInspection&InsuranceCompany,CT[I]

P.K.Chelian, FosterWheelerPowerGroup,Incorporated,NJ[M]

JosephN.Darguzas, EnviroPower,LLC,IL[IM]

SheltonEhrlich, PaloAlto,CA[SE]

WilliamBradleyGeorge, NovaScotiaPowerIncorporated,Canada[U]

DavidHabenicht, GlobalRiskConsultantsCorporation,IL[SE]

VicL.Jones, MerrickIndustriesIncorporated,FL[M]

DavidL.Kraft, Babcock&WilcoxCompany,OH[M]

DonaldL.Lueckenotte, Burns&McDonnellEngineeringCompany,MO[SE]

PaulH.Miller, SouthernCompanyServices,Incorporated,AL[U]

GaryE.Norman, ALSTOMPowerIncorporated,CT[M]

Alternates

KevinM.Estes, FosterWheelerPowerGroup,Incorporated,FL[M](Alt.toP.K.Chelian)

CopyrightNFPA

JohnP.O'Rourke, ALSTOMPowerIncorporated,CT[M](Alt.toG.E.Norman)

JamesM.Witt,Jr., SouthernCompanyServices,Incorporated,AL[U](Alt.toP.H.Miller)




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentsontheoperationandreductionofcombustionsystemhazardsandthepreventionofboilerfurnaceexplosionsoffluidizedbedboilers.Thisincludesallfuelsatanyheatinputrate.

TechnicalCommitteeonFundamentalsofCombustionSystemsHazards(BCSFUN)(Chapters14andAnnexesI,J,andK)

DaleP.Evely, ChairSouthernCompanyServices,Incorporated,AL[U]

KevinA.Alexeff, StockEquipmentCompany,OH[M]

CourtneyD.Alvey, Baltimore,MD[SE]

CarltonA.Bosfield, GrandBahamaPowerCompany,FL[U]

DavidA.Cowdrick, TampaElectricCompany,FL[U]

RichardA.Gallagher, ZurichServicesCorporation,DE[I]

ThomasB.George, MarshUSAIncorporated,MI[I]

TedJablkowski, NorthAmericanManufacturingCompany,CT[M]

RandyJ.Kleen, GeneralElectricCompany,TX[M]

RichardT.Long,Jr., Exponent,Incorporated,MD[SE]

PeterB.Matthews, HartfordSteamBoilerInspection&InsuranceCompany,CT[I]

FranciscoA.Palacios, BabcockPower,Incorporated,MA[M]

JohnR.Puskar, CECCombustionSafety,Incorporated,OH[SE]

CopyrightNFPA

CelsoG.Schmidt, ForneyCorporation,TX[M]

FranklinR.Switzer,Jr., Safe,Incorporated,IN[SE]

MichaelA.Walz, Burns&McDonnellEngineeringCompany,MO[SE]

HaroldR.Yates, HRY,Incorporated,MI[SE]

AllanJ.Zadiraka, TheBabcock&WilcoxCompany,OH[M]

Alternates

BryanR.Baesel, CECCombustionSafety,Incorporated,OH[SE](Alt.toJ.R.Puskar)

BarryJ.Basile, BabcockPower,Incorporated,MA[M](Alt.toF.A.Palacios)




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentsorportionsofdocumentsonfundamentals,maintenance,inspection,training,andsafetyforthereductionofcombustionsystemhazards.Fundamentalsshallspecificallyinclude definitions,furnaceexplosion/implosionprevention,manufacture,designandengineering,installation,coordinationofdesign,constructionandoperation,basicoperatingobjectives,equipmentrequirements,andcommissioning.

TechnicalCommitteeonHeatRecoverySteamGeneratorsandOtherCombustionTurbineExhaustSystems(BCSHRS)(Chapter8)

JohnVanName, ChairWashingtonGroupInternational,NY[SE]

HaroldHonath, SecretaryCoenCompanyIncorporated,CA[M]

DonaldW.Bairley, ALSTOMPowerIncorporated,CT[M]

RobertR.Balsbaugh, Burns&McDonnellEngineeringCompany,MO[SE]

RichardA.Brown, JohnZinkCompany,LLC,OK[M]

CopyrightNFPA

JohnH.Conroy, ForneyCorporation,TX[M]

DaleP.Evely, SouthernCompanyServices,Incorporated,AL[U]


GeorgeY.Keller, Burns&RoeEnterprises,Incorporated,NJ[SE]

StevenA.Lefton, AptechEngineeringServices,CA[SE]

BrianW.Moore, HartfordSteamBoilerInspection&InsuranceCompany,CT[I]

MartinC.Nygard, Nooter/Eriksen,MO[M]

MichaelC.Polagye, FMGlobal,MA[I]

JimmieJ.Schexnayder, EntergyCorporation,LA[U]

PhilipF.Souers, SiemensPowerCorporation,FL[M]

JosephM.Vavrek, Sargent&Lundy,LLC,IL[SE]

JamesP.Walawender, Black&VeatchCorporation,KS[SE]

Alternates

AlfredJ.Beaty, ForneyCorporation,TX[M](Alt.toJ.H.Conroy)

SandaBrumaru, Burns&RoeEnterprises,NJ[SE](Alt.toG.Y.Keller)

RodneyT.Crockett, JohnZinkCompany,LLC,OK[M](Alt.toR.A.Brown)

RickFiorenza, CoenCompanyIncorporated,CA[M](Alt.toH.Honath)

RobertP.Kaltenbach, Burns&McDonnellEngineeringCompany,MO[SE](Alt.toR.R.Balsbaugh)

ChristopherJ.Lech, ALSTOMPowerIncorporated,CT[M](Alt.toD.W.Bairley)


CopyrightNFPA

GeorgeN.Pyros, SiemensPowerGeneration,FL[M](Alt.toP.F.Souers)

RonaldRispoli, EntergyCorporation,AR[U](Alt.toJ.J.Schexnayder)




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentscoveringtheoperationofheatrecoverysteamgeneratorsandothercombustionturbineexhaustsystems,andtherelatedreductionofcombustionsystemhazardsandpreventionofexplosions.Thisincludesallfuelsatanyheatinputrate.

TechnicalCommitteeonMultipleBurnerBoilers(BCSMBB)(Chapter6andAnnexesB,C,andD)

HaroldR.Yates, ChairHRY,Incorporated,MI[SE]

BernardHrul, SecretaryAllenBradleyCompany,MI[U]


BillBass, ForneyCorporation,TX[M]

FrankJ.Bennett, MirantMidAtlantic,MD[U]


JohnJ.Eibl, TheDuPontCompany,TN[U]

DaleP.Evely, SouthernCompanyServices,Incorporated,AL[U]

KennethJoeFrazier, SaltRiverProject,AZ[U]


KrisA.Gamble, Black&VeatchCorporation,KS[SE]

GeorgeY.Keller, Burns&RoeEnterprises,Incorporated,NJ[SE]

CopyrightNFPA

RichardKimball, HFControlsCorporation,TX[M]

DanielJ.Lee, ABBIncorporated,OH[M]

W.ScottMatz, InvensysProcessSystems,TX[M]

PeterMcKenna, Stone&Webster,Incorporated,MA[SE]

LalitM.Mehta, CoenCompany,Incorporated,CA[M]

TerryA.Nelson, YokogawaCorporationofAmerica,TX[M]

JohnP.O'Rourke, ALSTOMPowerIncorporated,CT[M]

FranciscoA.Palacios, BabcockPower,Incorporated,MA[M]

MichaelC.Polagye, FMGlobal,MA[I]

GlennA.Raney, PremierConsultingServices,TX[SE]

ThomasD.Russell, Honeywell,Incorporated,TX[M]

JimmieJ.Schexnayder, EntergyCorporation,LA[U]


JosephM.Vavrek, Sargent&Lundy,LLC,IL[SE]

MichaelA.Walz, Burns&McDonnellEngineeringCompany,MO[SE]


HenryK.Wong, WashingtonGroupInternational,NJ[SE]

AllanJ.Zadiraka, TheBabcock&WilcoxCompany,OH[M]

Alternates

JohnE.Bollinger, TheBabcock&WilcoxCompany,OH[M](Alt.toA.J.Zadiraka)

JohnC.deRuyter, TheDuPontCompany,Incorporated,DE[U](Alt.toJ.J.Eibl)

RonaldJ.Fleming, ABBIncorporated,OH[M](Alt.toD.J.Lee)

CopyrightNFPA

StevenL.Hawkins, Black&VeatchCorporation,KS[SE](Alt.toK.A.Gamble)

KennethHurlburt, BabcockPower,Incorporated,MA[M](Alt.toF.A.Palacios)

RobertP.Kaltenbach, Burns&McDonnellEngineeringCompany,MO[SE](Alt.toM.A.Walz)


GaryE.Norman, ALSTOMPowerIncorporated,CT[M](Alt.toJ.P.O'Rourke)

MarkA.Ratcliffe, InvensysProcessSystems,TX[M](Alt.toW.S.Matz)

RonaldRispoli, EntergyCorporation,AR[U](Alt.toJ.J.Schexnayder)

WesleyJ.Schulze, CoenCompany,Incorporated,CA[M](Alt.toL.M.Mehta)

GeorgeP.Seroka, DTEEnergy/DetroitEdisonCompany,MI[U](VotingAlt.toDTEEnergyRep.)

JamesM.Witt,Jr., SouthernCompanyServices,Incorporated,AL[U](Alt.toD.P.Evely)

Nonvoting

S.Dharmalingam, BharatHeavyElectricalsLimited,India[M]




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentscoveringthereductionofcombustionsystemhazardsandthepreventionofboilerfurnaceexplosionsandimplosionsinmultipleburnerboilerswithaheatinputrateof12,500,000Btu/hrandabove.Thisincludesallfuels.

CopyrightNFPA

TechnicalCommitteeonPulverizedFuelSystems(BCSPFS)(Chapter9)

MichaelB.Doherty, ChairAmericanElectricPowerServiceCorporation,OH[U]


DavidA.Cowdrick, TampaElectricCompany,FL[U]

JohnC.deRuyter, TheDuPontCompany,Incorporated,DE[U]

RoryG.Eastman, ALSTOMPowerIncorporated,CT[M]

KennethL.Gardner, MetsoIndustries,PA[M]

RoderickJ.Hossfeld, Jenike&Johanson,Incorporated,MA[SE]

WalterE.Keiser, GeorgiaPowerCompany,GA[U]

KiranR.Patel, BabcockPower,Incorporated,MA[M]

JonathanR.Pranitis, FosterWheelerEnergyCorporation,NJ[M]

ClevelandB.Skinker, BechtelPowerCorporation,MD[SE]

WilliamA.(Andy)Smith, GlobalRiskConsultantsCorporation,GA[SE]

Alternates

AlanJ.Seibert, ALSTOMPowerIncorporated,CT[M](Alt.toR.G.Eastman)




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentsontheoperationanddesignrequirementsofpulverizedfuelsystemsandreductionofhazardsassociatedwiththosesystems.Thisincludesallcarbonaceoussolidfuelsatanyheatinputrate.

TechnicalCommitteeonSingleBurnerBoilers(BCSSBB)(Chapter5)

CopyrightNFPA

JohnJ.Eibl, ChairTheDuPontCompany,TN[U]


CarltonA.Bosfield, GrandBahamaPowerCompany,FL[U]

JohnT.Connor, Burns&McDonnellEngineeringCompany,MO[SE]


G.F.(Jerry)Gilman, SISTech,OH[SE]

TedJablkowski, NorthAmericanManufacturingCompany,CT[M]

RobertA.Koehler, LibertyMutualProperty,TX[I]Rep.PropertyCasualtyInsurersAssociationofAmerica

GlennA.Raney, PremierConsultingServices,TX[SE]

GaryJ.Shrider, Babcock&WilcoxCompany,OH[M]


JacquesVanHeijningen, SiemensBuildingTechnologies,Inc.,IL[M]

J.A.RedWagner, Fireye,NJ[M]

ChrisWille, CoenCompany,Incorporated,CA[M]


Alternates




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentsonthereductionofcombustionsystemhazardsandthepreventionofboilerfurnaceexplosionsinsingleburnerboilerswithaheatinputrateof12,500,000Btu/hrandabove.Thisincludesallfuels.

CopyrightNFPA

TechnicalCommitteeonStokerOperations(BCSSTO)(Chapter10andAnnexesFandG)

JohnC.deRuyter, ChairTheDuPontCompany,Incorporated,DE[U]

J.MikeCantrell, TheMcBurneyCorporation,GA[IM]

AndrewK.Dant, CogentrixEnergy,Incorporated,NC[U]

JohnHoh, NationalBoardofBoiler&PressureVesselInspectors,OH[E]

Alternates




CommitteeScope:ThisCommitteeshallhaveprimaryresponsibilityfordocumentscoveringtheoperationofstokersandrelatedfuelburningequipment.Thisincludesallfuelsatanyheatinputrate.

NFPA85BoilerandCombustionSystemsHazardsCode

2007Edition

IMPORTANTNOTE:ThisNFPAdocumentismadeavailableforusesubjecttoimportantnoticesandlegaldisclaimers.ThesenoticesanddisclaimersappearinallpublicationscontainingthisdocumentandmaybefoundundertheheadingImportantNoticesandDisclaimersConcerningNFPADocuments.TheycanalsobeobtainedonrequestfromNFPAorviewedatwww.nfpa.org/disclaimers.

NOTICE:Anasterisk(*)followingthenumberorletterdesignatingaparagraphindicatesthatexplanatorymaterialontheparagraphcanbefoundinAnnexA.

Changesotherthaneditorialareindicatedbyaverticalrulebesidetheparagraph,table,orfigureinwhichthechangeoccurred.Theserulesareincludedasanaidtotheuserinidentifyingchangesfromthepreviousedition.Whereoneormorecompleteparagraphshavebeendeleted,thedeletionisindicatedbyabullet()betweentheparagraphsthatremain.

Areferenceinbrackets[]followingasectionorparagraphindicatesmaterialthathasbeenextractedfromanotherNFPAdocument.Asanaidtotheuser,thecompletetitleandedition

CopyrightNFPA

ofthesourcedocumentsforextractsinmandatorysectionsofthedocumentaregiveninChapter2andthoseforextractsininformationalsectionsaregiveninAnnexN.Editorialchangestoextractedmaterialconsistofrevisingreferencestoanappropriatedivisioninthisdocumentortheinclusionofthedocumentnumberwiththedivisionnumberwhenthereferenceistotheoriginaldocument.Requestsforinterpretationsorrevisionsofextractedtextshallbesenttothetechnicalcommitteeresponsibleforthesourcedocument.

InformationonreferencedpublicationscanbefoundinChapter2andAnnexN.

Chapter1Administration

1.1*Scope.

Thiscodeshallapplytosingleburnerboilers,multipleburnerboilers,stokers,andatmosphericfluidizedbedboilerswithafuelinputratingof3.7MWt(12.5millionBtu/hr)orgreater,topulverizedfuelsystems,tofiredorunfiredsteamgeneratorsusedtorecoverheatfromcombustionturbines[heatrecoverysteamgenerators(HRSGs)],andtoothercombustionturbineexhaustsystems.

1.1.1 Thiscodeshallcoverdesign,installation,operation,maintenance,andtraining.

1.1.2 Thiscodeshallcoverstrengthofthestructure,operationandmaintenanceprocedures,combustionanddraftcontrolequipment,safetyinterlocks,alarms,trips,andotherrelatedcontrolsthatareessentialtosafeequipmentoperation.

1.1.3 CoordinationofthedesignandoperatingproceduresoftheboilerfurnaceorHRSGsystemandanyfluegascleanupsystemsdownstreamofthepostcombustiongaspassesshallberequired.Suchcoordinationshallincluderequirementsforensuringacontinuousflowpathfromthecombustionairinletthroughthestack.

1.1.4 Chapter5,SingleBurnerBoilers,coverssingleburnerboilersthatfirethefollowingfuels:

(1) Fuelgasasdefinedin 3.3.74.

(2)* Othergashavingacalorificvalueandcharacteristicssimilartonaturalgas

(3) Fueloilasdefinedin 3.3.73.3

(4) Fuelgasandfueloilthatarefiredsimultaneouslyforfueltransfer

(5) Fuelgasandfueloilthatarefiredsimultaneouslyandcontinuously

1.1.5 Chapter6,MultipleBurnerBoilers,coversmultipleburnerboilersfiringoneormoreofthefollowing:

(1) Fuelgas,asdefinedin 3.3.74

(2) Fueloil,asdefinedin 3.3.73.3

(3) Pulverizedcoal,asdefinedin 3.3.73.2.1

(4) Simultaneousfiringofmorethanoneofthefuelsstatedin1.1.5(1)through1.1.5(3)

CopyrightNFPA

1.1.6 Chapter7,AtmosphericFluidizedBedBoilers,coversatmosphericfluidizedbedboilers.

1.1.7* Chapter8,HeatRecoverySteamGeneratorsandOtherCombustionTurbineExhaustSystems,coversHRSGsystemsorothercombustionturbineexhaustsystems.

1.1.8 Chapter9,PulverizedFuelSystems,coverspulverizedfuelsystems,beginningwiththerawfuelbunker,whichisupstreamofthepulverizer,andisthepointatwhichprimaryairentersthepulverizingsystem,andterminatingatthepointwherepressurecanberelievedbyfuelbeingburnedorcollectedinadevicethatisbuiltinaccordancewiththiscode.Thepulverizedfuelsystemshallincludetheprimaryairducts,whichareupstreamofthepulverizer,toapointwherepressurecanberelieved.

1.1.9 Chapter10,Stokers,coversboilersusingastokertofirethefollowingfuels:

(1) Coal

(2) Wood

(3) Refusederivedfuel(RDF)

(4) Municipalsolidwaste(MSW)

(5) Othersolidfuels

1.1.9.1 Wheresolidfuelisfiredsimultaneouslywithotherfuels(e.g.,asolidfuelstokerfiredincombinationwithfuelgas,fueloil,orpulverizedauxiliaryfuel),additionalcontrolsandinterlocksshallincludethosecoveredinChapters5,6,and9.

ExceptionNo.1:ThepurgerequirementsofChapters5and6shallnotberequiredwhenthestokerisfiringandtheboilerisonline.Inthosecases,ifnocoolingairisbeingprovidedtotheauxiliaryburners,apurgeoftheirassociatedairsupplyductsshallbeprovided.

ExceptionNo.2:WherefueloilorfuelgasisfiredinasupervisedmanualsysteminaccordancewithChapter5,theexcessivesteampressureinterlockshallnotberequired.

1.2*Purpose.

Thepurposeofthiscodeshallbetocontributetooperatingsafetyandtopreventuncontrolledfires,explosions,andimplosionsinequipmentdescribedinSection 1.1.

1.2.1 Thiscodeshallestablishminimumrequirementsforthedesign,installation,operation,training,andmaintenanceofpulverizedfuelsystems,boilers,HRSGs,combustionturbineexhaustsystems,andtheirsystemsforfuelburning,airsupply,andcombustionproductsremoval.

1.2.2 Thiscodeshallrequirethecoordinationofoperatingprocedures,controlsystems,interlocks,andstructuraldesign.

1.2.3 Thiscodeshallnotbeusedasadesignhandbook.

1.2.3.1 Adesignercapableofapplyingmorecompleteandrigorousanalysistospecialor

CopyrightNFPA

unusualproblemsshallhavelatitudeinthedevelopmentofsuchdesigns.

1.2.3.2 Insuchcases,thedesignershallberesponsiblefordemonstratinganddocumentingthevalidityoftheproposeddesign.

1.3Application.

1.3.1 Thiscodeshallapplytonewinstallationsandtomajoralterationsorextensionsthatarecontractedforsubsequenttotheeffectivedateofthiscode.

1.3.2 Processheatersusedinchemicalandpetroleummanufacture,whereinsteamgenerationisincidentaltotheoperationofaprocessingsystem,shallnotbecoveredbythiscode.

1.4*Retroactivity.

Theprovisionsinthiscodereflectaconsensusofwhatisnecessarytoprovideanacceptabledegreeofprotectionfromthehazardsaddressedinthiscode,atthetimethecodewasissued.

1.4.1 Unlessotherwisespecified,theprovisionsinthiscodeshallnotapplytofacilities,equipment,structures,orinstallationsthatexistedorwereapprovedforconstructionorinstallationpriortotheeffectivedateofthecode.Wherespecified,theprovisionsinthiscodeshallberetroactive.

1.4.2 Inthosecaseswheretheauthorityhavingjurisdictiondeterminesthattheexistingsituationpresentsanunacceptabledegreeofrisk,theauthorityhavingjurisdictionshallbepermittedtoapplyretroactivelyanyportionsofthiscodedeemedappropriate.

1.4.3 Theretroactiverequirementsofthiscodeshallbepermittedtobemodifiediftheirapplicationclearlywouldbeimpracticalinthejudgmentoftheauthorityhavingjurisdiction,andonlywhereitisclearlyevidentthatareasonabledegreeofsafetyisprovided.

1.5Equivalency.

Nothinginthiscodeisintendedtopreventtheuseofsystems,methods,ordevicesofequivalentorsuperiorquality,strength,fireresistance,effectiveness,durability,andsafetyoverthoseprescribedbythiscode.

1.5.1 Technicaldocumentationshallbesubmittedtotheauthorityhavingjurisdictiontodemonstrateequivalency.

1.5.2 Thesystem,method,ordeviceshallbeapprovedfortheintendedpurposebytheauthorityhavingjurisdiction.

1.6Enforcement.

Thiscodeshallbeadministeredandenforcedbytheauthorityhavingjurisdictiondesignatedbythegoverningauthority.(SeeAnnexIforsamplewordingforenablinglegislation.)

CopyrightNFPA

Chapter2ReferencedPublications

2.1General.

Thedocumentsorportionsthereoflistedinthischapterarereferencedwithinthiscodeandshallbeconsideredpartoftherequirementsofthisdocument.

2.2NFPAPublications.

NationalFireProtectionAssociation,1BatterymarchPark,Quincy,MA021697471.

NFPA30,FlammableandCombustibleLiquidsCode,2003edition.

NFPA31,StandardfortheInstallationofOilBurningEquipment,2006edition.

NFPA54,NationalFuelGasCode,2006edition.

NFPA69,StandardonExplosionPreventionSystems,2002edition.

NFPA70,NationalElectricalCode,2005edition.

2.3OtherPublications.

2.3.1AISCPublications.

AmericanInstituteofSteelConstruction,OneEastWackerDrive,Suite700,Chicago,IL60601.

AISCASD,SpecificationsforStructuralSteelBuildingsAllowableStressDesignandPlasticDesign,1989,includingsupplementNo.1,2001.

AISCLRFD,LoadandResistanceFactorDesignforStructuralSteelBuildings,1999.

2.3.2ANSIPublications.

AmericanNationalStandardsInstitute,Inc.,25West43rdStreet,4thFloor,NewYork,NY10036.

ANSIK61.1,SafetyRequirementsfortheStorageandHandlingofAnhydrousAmmonia,1999.

ANSI/FCI702,ControlValveSeatLeakage,2006.

2.3.3ASCEPublications.

AmericanSocietyofCivilEngineers,1801AlexanderBellDrive,Reston,VA201914400.

ASCE7,MinimumDesignLoadsforBuildingsandOtherStructures,2002.

2.3.4ASMEPublications.

AmericanSocietyofMechanicalEngineers,ThreeParkAvenue,NewYork,NY100165990.

CopyrightNFPA

ASMEB31.1,PowerPiping,1998.

ASMEB31.3,ProcessPiping,1999.

2.3.5ASTMPublications.

ASTMInternational,100BarrHarborDrive,P.O.BoxC700,WestConshohocken,PA194282959.

ASTMD388,StandardClassificationofCoalsbyRank,1999.

ASTMD396,StandardSpecificationforFuelOils,1998.

ASTMD409,StandardTestMethodforGrindabilityofCoalbytheHardgroveMachineMethod,1997.

ASTMD1655,StandardSpecificationforAviationTurbineFuels,1998.

ASTMD2880,StandardSpecificationforGasTurbineFuelOils,1998.

2.3.6MilitarySpecifications.

DepartmentofDefenseSingleStockPoint,DocumentAutomationandProductionService,Building4/D,700RobbinsAvenue,Philadelphia,PA191115094.

MILT5624,TurbineFuel,Aviation,GradeJP4,JP5,andJP5/JP8ST,1995.

2.3.7OtherPublications.

MerriamWebstersCollegiateDictionary,11thedition,MerriamWebster,Inc.,Springfield,MA,2003.

2.4ReferencesforExtractsinMandatorySections.

NFPA13D,StandardfortheInstallationofSprinklerSystemsinOneandTwoFamilyDwellingsandManufacturedHomes,2007edition.

NFPA40,StandardfortheStorageandHandlingofCelluloseNitrateFilm,2007edition.

NFPA69,StandardonExplosionPreventionSystems,2002edition.

NFPA72,NationalFireAlarmCode,2007edition.

NFPA850,RecommendedPracticeforFireProtectionforElectricGeneratingPlantsandHighVoltageDirectCurrentConverterStations,2005edition.

NFPA853,StandardfortheInstallationofStationaryFuelCellPowerSystems,2007edition.

Chapter3Definitions

3.1General.

Thedefinitionscontainedinthischaptershallapplytothetermsusedinthiscode.Where

CopyrightNFPA

termsarenotdefinedinthischapterorwithinanotherchapter,theyshallbedefinedusingtheirordinarilyacceptedmeaningswithinthecontextinwhichtheyareused.MerriamWebstersCollegiateDictionary,11thedition,shallbethesourcefortheordinarilyacceptedmeaning.

3.2NFPAOfficialDefinitions.

3.2.1*Approved.Acceptabletotheauthorityhavingjurisdiction.

3.2.2*AuthorityHavingJurisdiction(AHJ).Anorganization,office,orindividualresponsibleforenforcingtherequirementsofacodeorstandard,orforapprovingequipment,materials,aninstallation,oraprocedure.

3.2.3*Code.Astandardthatisanextensivecompilationofprovisionscoveringbroadsubjectmatterorthatissuitableforadoptionintolawindependentlyofothercodesandstandards.

3.2.4Labeled.Equipmentormaterialstowhichhasbeenattachedalabel,symbol,orotheridentifyingmarkofanorganizationthatisacceptabletotheauthorityhavingjurisdictionandconcernedwithproductevaluation,thatmaintainsperiodicinspection ofproductionoflabeledequipmentormaterials,andbywhoselabelingthemanufacturerindicatescompliancewithappropriatestandardsorperformanceinaspecifiedmanner.

3.2.5*Listed.Equipment,materials,orservicesincludedinalistpublishedbyanorganizationthatisacceptabletotheauthorityhavingjurisdictionandconcernedwithevaluationofproductsorservices,thatmaintainsperiodicinspectionofproduction oflistedequipmentormaterialsorperiodicevaluationofservices,andwhoselistingstatesthateithertheequipment,material,orservicemeetsappropriatedesignatedstandardsorhasbeentestedandfoundsuitableforaspecifiedpurpose.

3.2.6Shall.Indicatesamandatoryrequirement.

3.2.7Should.Indicatesarecommendationorthatwhichisadvisedbutnotrequired.

3.2.8Standard.Adocument,themaintextofwhichcontainsonlymandatoryprovisionsusingthewordshalltoindicaterequirementsandwhichisinaformgenerallysuitableformandatoryreferencebyanotherstandardorcodeorforadoptionintolaw.Nonmandatoryprovisionsshallbelocatedinanappendixorannex,footnote,orfineprintnoteandarenottobeconsideredapartoftherequirementsofastandard.

3.3GeneralDefinitions.

3.3.1Agglomerating.Acharacteristicofcoalthatcausescokingonthefuelbedduringvolatilization.

3.3.2Agglomeration.Alkalicompoundscanattachtobedmaterialparticles.Thesecompoundscanhavelowmeltingpointsandcausethebedparticlestosticktoeachothertoformagglomerates.

3.3.3Air.

3.3.3.1AuxiliaryAir.Airthatissuppliedfromanauxiliarysourcetomaintainaminimum

CopyrightNFPA

fuelmixturevelocityinburnerpiping.

3.3.3.2CombustionAir.Airusedtoreactwiththefuelinthecombustionprocess.Forductburners,thisgenerallyiscombustionturbineexhaust.

3.3.3.3DesignFullLoadMassAirflow.Theairflowrequiredtoachievenameplatefullload.ForthepurposesofChapter6,MultipleBurnerBoilers,itistheflowrequiredtoachievenameplatefullloadbasedontheoriginaldesignfuelasdefinedbytheboilerequipmentmanufacturer.

3.3.3.4*ExcessAir.Airsuppliedforcombustioninexcessoftheoreticalair.

3.3.3.5OverfireAir.Airsuppliedforcombustionthatisadmittedintothefurnaceatapointabovetheburnersorfuelbed.

3.3.3.6PrimaryAir.Airsuppliedforcombustionthatisadmittedintothefurnacethroughaburnerpremixedwiththefuel.

3.3.3.6.1PrimaryAir(inaBubblingFluidizedBed).Thatportionoftotalairusedtotransportorinjectfuelorsorbentandtorecyclematerialtothebed.

3.3.3.6.2PrimaryAir(inaCirculatingFluidizedBed).Thatportionoftotalairintroducedatthebaseofthecombustorthroughtheairdistributor.

3.3.3.6.3PrimaryAir(forthepurposesofequipmentwithinthescopeofChapter8,HeatRecoverySteamGeneratorsandOtherCombustionTurbineExhaustSystems).Theairthatiscontainedinthecombustionturbineexhaust.

3.3.3.6.4PrimaryAir(inaPulverizedFuelSystem).Inapulverizedfuelsystem,canbeeitherairorafluegas/airmixture,andcansimultaneouslyalsobepulverizerairand/ortransportair.

3.3.3.7PulverizerAir.Airorinertgasthatisintroducedintothepulverizertodrythefuel,aidinpulverizationandclassification,andconveythepulverizedfuelfromthepulverizer.

3.3.3.8SealAir.Airorinertgassuppliedtoanydeviceatsufficientpressureforthespecificpurposeofminimizingcontamination.

3.3.3.9SecondaryAir.Airforcombustionsuppliedtotheburnersorfuelbedinadditiontotheprimaryair.

3.3.3.9.1SecondaryAir(inaBubblingFluidizedBed).Thatportionoftheairintroducedthroughtheairdistributor.

3.3.3.9.2SecondaryAir(inaCirculatingFluidizedBed).Thatairthatentersthecombustoratlevelsabovetheairdistributor.

3.3.3.9.3SecondaryAir(inaSingleorMultipleBurnerBoiler).Thatportionoftheairenteringthroughtheairregisters.

3.3.3.10TemperingAir.Coolairaddedtothehotprimaryairorgastomodifyitstemperature.

3.3.3.11TheoreticalAir.Thechemicallycorrectquantityofairneededforcomplete

CopyrightNFPA

combustionofagivenquantityofaspecificfuel.

3.3.3.12TransportAir.Airorinertgasthatisusedtoconveypulverizedfuel.

3.3.3.12.1TransportAir(inaFluidizedBed).Theairusedtoconveyorinjectsolidfuelorsorbentortorecyclematerial.

3.3.3.13UndergrateAir.Combustionairintroducedbelowthegrate.

3.3.4AirChange.Aquantityofair,providedthroughafuelburner,equaltothevolumeoffurnaceandboilergaspasses.

3.3.5AirRich.Aratioofairtofuelsuppliedtoacombustionchamberthatprovidesmorethantheminimumexcessairneededforoptimumcombustionofthefuel.

3.3.6Alarm.Anaudibleorvisiblesignalindicatinganoffstandardorabnormalcondition.

3.3.7Alteration.Achangeormodificationthatresultsinadeviationfromtheoriginaldesignspecificationsorcriteria.

3.3.8Annunciator.Adeviceindicatinganoffstandardorabnormalconditionbybothvisualandaudiblesignals.

3.3.9AtmosphericFluidizedBedCombustion.Afuelfiringtechniqueusingafluidizedbedoperatingatnearatmosphericpressureonthefireside.

3.3.10Atomizer.Thedeviceinaburnerthatbreaksdownliquidfuelintoafinelydividedstate.

3.3.10.1MechanicalAtomizer.Thedeviceinaburnerthatbreaksdownliquidfuelintoafinelydividedstatewithoutusinganatomizingmedium.

3.3.11AtomizingMedium.Asupplementaryfluid,suchassteamorair,thatassistsinbreakingdownliquidfuelintoafinelydividedstate.

3.3.12AugmentedAirFiring.Supplementaryfiringwiththeadditionofairattheductburnerstosupportandstabilizecombustionortoreduceemissions.

3.3.13*AutoignitionTemperature(AIT).Theminimumtemperaturerequiredtoinitiateorcauseselfsustainedcombustionofasolid,liquid,orgasindependentlyoftheheatingorheatedelement.

3.3.14BedCompartment.Segmentsofafluidizedbed,whichmightbeindividuallycontrolledwithrespecttocombustionairflowandfuelfeed.

3.3.15BedDrain.Anopeningprovidedintheenclosureofafluidizedbedfortheremovalofspentbedmaterialandanytrampmaterial.

3.3.16BedMaterial.Granularparticlesthatcomposeafluidizedbed.

3.3.17BedTemperature.Theaveragetemperatureofafluidizedbed.

3.3.18Bin.Anenclosuretostorepulverizedfuel.

3.3.19BinSystem(StorageSystem).Asysteminwhichthefuelispulverizedandstoredin

CopyrightNFPA

binsfromwhichitiswithdrawnthroughfeeders,asneeded,forburning.

3.3.20Boiler.Aclosedvesselinwhichwaterisheated,steamisgenerated,steamissuperheated,oranycombinationthereofbytheapplicationofheatfromcombustiblefuelsinaselfcontainedorattachedfurnace.

3.3.21BoilerEnclosure.Thephysicalboundaryforallboilerpressurepartsandforthecombustionprocess.

3.3.22BottomAirAdmission.Amethodofintroducingairtoachainortravelinggratestokerunderthestoker.

3.3.23BubblingFluidizedBed(BFB).Afluidizedbedinwhichthefluidizingvelocityislessthantheterminalvelocityofindividualbedparticlesandinwhichpartofthefluidizinggaspassesthroughthebedasbubbles.

3.3.24Bunker.Anenclosuretostorerawfuel.

3.3.25Burner.Adeviceorgroupofdevicesfortheintroductionoffuelandairintoacombustionchamberatthevelocity,turbulence,andconcentrationrequiredtomaintainignitionandcombustionoffuel.

3.3.25.1AuxiliaryLoadCarryingBurner.Inafluidizedbedboiler,aburnerwhoseprimarypurposeisloadcarrying,locatedoverthebedandhavingitsownairsupply.

3.3.25.2*DuctBurner.Aburner,mountedinaductordischargingintoaduct,usedtoheattheair,fluegas,orcombustionturbineexhaustgasintheduct.

3.3.25.3OverBedBurner.Inafluidizedbedboiler,awarmupburnerlocatedabovethebedandfiringoverorintothebed.

3.3.25.4WarmUpBurner(WarmUpGun).Aburner,usuallysmallerthanthemainburner,thatisignitedbyanotherignitionsourceandisusedtowarmuptheboiler.Incaseswhereitisusedasanigniter,itsclassificationshallbeverifiedbytest.

3.3.25.4.1WarmUpBurner(inaFluidizedBedBoiler).Aburnerhavingitsownairsupplyusedtowarmupthebedtotheignitiontemperatureofthemainfuel.Thewarmupburneralsocanbeusedforlimitedloadcarrying.

3.3.26*BurnerManagementSystem.Thecontrolsystemdedicatedtocombustionsafetyandoperatorassistanceinthestartingandstoppingoffuelpreparationandburningequipmentandforpreventingmisoperationofanddamagetofuelpreparationandburningequipment.

3.3.26.1AutomaticBurnerManagementSystemNonrecycling.Aburnermanagementsystembywhichafurnaceispurgedandaburnerisstarted,ignited,andstoppedautomaticallybutdoesnotrecycleautomatically.

3.3.26.2AutomaticBurnerManagementSystemRecycling.Aburnermanagementsystembywhichafurnaceispurgedandaburnerisstarted,ignited,andstoppedautomaticallyandrecyclesonapresetpressurerange.

3.3.26.3ManualBurnerManagementSystem.Aburnermanagementsystembywhichafurnaceispurgedandaburnerisstarted,ignited,andstoppedmanually.

CopyrightNFPA

3.3.26.4Manual,SupervisedBurnerManagementSystem.Aburnermanagementsystembywhichafurnaceispurgedandaburnerisstarted,ignited,andstoppedmanually.Interlocksareincludedtoensurethattheoperationfollowsestablished,properprocedures.

3.3.27BypassStack.AstackappliedinadditiontoandseparatefromthenormalHRSGexhauststackthatallowscombustionturbineexhaustgastoflowindependentlytotheatmosphere.

3.3.28Calcination.Theendothermicchemicalreactionthattakesplacewhenconvertingcalciumcarbonateorcalciumhydroxidetocalciumoxide.

3.3.29CalciumtoSulfurMolarRatio(Ca/S).Theratioofthetotalmolesofcalciuminthesorbentfedtotheboilertothetotalmolesofsulfurinthefuelfedtotheboiler.

3.3.30Char.Theunburnedcombustiblesinsolidformcombinedwithaportionofthefuelashandsorbent.

3.3.31CinderReturn.Inastokerfiredboiler,anapparatusforthereturnofcollectedcinderstothefurnace,eitherdirectlyorwiththefuel.

3.3.32CirculatingFluidizedBed(CFB).Afluidizedbedinwhichthefluidizingvelocitiesexceedtheterminalvelocityofindividualbedparticles.

3.3.33Classifier.Adevicetocontrolpulverizedfuelparticlesizedistribution.

3.3.34Coal.See3.3.73.2.

3.3.35CokingPlate.Aplateadjacenttoagratethroughwhichnoairpassesandonwhichcoalisplacedfordistillingthecoalvolatilesbeforethecoalismovedontothegrate.

3.3.36CombustionChamber.TheportionoftheboilerorHRSGenclosureintowhichthefuelisfed,ignited,andburned.

3.3.37CombustionTurbine.Aturbineinwhichtherotatingelementisactuatedbythepressureofcombustiongasesoncurvedvanes.

3.3.38CombustionTurbineExhaustSystems.Allductworkfromthecombustionturbineexhausttothestack,includinganyemissioncontrolsystemscontainedwithintheexhaustflowpath.

3.3.39CombustionTurbineRunback.ThecontrolledunloadingofacombustionturbinetoalevelrequiredbyHRSGorotherequipmentcontroldemands.

3.3.40CommercialOperation.Thedatethatthefullplantcapacityisformallyaddedtothepowergrid.

3.3.41Commissioning.Thetimeperiodofplanttestingandoperationbetweeninitialoperationandcommercialoperation.

3.3.42ConfinedSpace.Anyworklocationorenclosureinwhicheitherofthefollowingexists:(1)thedimensionsaresuchthatapersonwhois1.8m(6ft)tallcannotstandupinthemiddleofthespaceorextendhisorherarmsinalldirectionswithouthittingtheenclosure,(2)accesstoorfromtheenclosureisbymanhole,hatch,port,orotherrelatively

CopyrightNFPA

smallopeningthatlimitsingressandegresstoonepersonatatime.Confinedspacesincludebutarenotlimitedtothefollowing:pulverizers,ducts,heaters,windboxes,cyclones,coaldustcollectors,furnaces,bunkers,binsandHRSGs.

3.3.43ContinuousTrendDisplay.Adedicatedvisualdisplayofanoperatingtrend(s)byanyinstrumentsuchasacathoderaytube(CRT),chartrecorder,orotherdevicetoquantifychangesinthemeasuredvariable(s).

3.3.44ControlSystem.

3.3.44.1BoilerControlSystem.Thegroupofcontrolsystemsthatregulatestheboilerprocess,includingthecombustioncontrolsystembutnottheburnermanagementsystem.

3.3.44.2CombustionControlSystem.Thecontrolsystemthatregulatesthefurnacefuelandairinputstomaintaintheairfuelratiowithinthelimitsthatarerequiredforcontinuouscombustionandstableflamethroughouttheoperatingrangeoftheboilerinaccordancewithdemand.

3.3.44.2.1CombustionControlSysteminaFluidizedBed.Inafluidizedbed,thecontrolsystemthatregulatesthefurnacefuelinput,furnaceairinput,bedinventory,andotherbedheattransfermechanismstomaintainthebedtemperatureandtheairfuel ratiowithinthelimitsnecessaryforcontinuouscombustionandstablebedoperationthroughouttheoperatingrangeoftheboilerinaccordancewithdemand.

3.3.44.2.2CombustionControlSysteminHRSGSystems.InHRSGsystems,thecontrolsystemthatregulatesthefuelinputandair,whereapplicable,tomaintaincontinuouscombustionandstableflame.

3.3.44.3HRSGControlSystem.ThegroupofcontrolsystemsthatregulatetheHRSGprocess,includingthecombustioncontrolsystembutnottheburnermanagementsystem.

3.3.44.4StartUpCombustionControlSystem.Acontrolsystemusedtoregulateandmaintainproperairfuelratioduringthestartupperiodwherethecustomaryindexes,suchaspressure,temperature,load,orflow,thatmotivatethenormalautomaticcombustioncontrolsystemarenotavailableorsuitable.

3.3.45Crusher.Adeviceforreducingthesizeofsolidfuels.

3.3.46Damper.Avalveorplateforcontrollingdraftortheflowofgases,includingair.[853,2007]

3.3.46.1ShutoffDamper.Aclosefittingdampertopreventflowandminimizeleakageofairorfluegasintoanysystemcomponent.

3.3.47DesignFullLoadMassAirflow.See3.3.3.3.

3.3.48DirectFiredSystem(UnitSystem).Asysteminwhichthefuelispulverizedanddeliveredinsuspensiondirectlytotheburner(s).

3.3.49DirectionalBlocking.Aninterlockthat,upondetectionofasignificanterrorinfurnacepressureorHRSGprocessvariables,actstoinhibitthemovementofallappropriatefinalcontrolelementsinthedirectionthatwouldincreasetheerror.

CopyrightNFPA

3.3.50Distributor/Divider.Adevicethatsplitsasinglestreamofpulverizedcoalandprimaryairintotwoormorestreams.

3.3.51DragSeal.Inachaingratestoker,thehingedplaterestingagainstthereturningchainandusedtosealtheaircompartments.

3.3.52DripLeg.Achamberofamplevolume,withsuitablecleanoutanddrainconnections,overwhichfuelgasispassedsothatliquidsandsolidsaretrapped.

3.3.53DumpPlate.Inastokerfiredfurnace,anashsupportingplatefromwhichashescanbedischargedfromonesideoftheplatebyrotationoftheplate.

3.3.54DustCollector.Anauxiliaryseparatorthatisusedtoseparatethefueldustfromtheairorinertgaspriortodischargeofthelatterfromthesystem.

3.3.55Elutriation.Theselectiveremovaloffinesolidsfromafluidizedbedbyentrainmentintheupwardflowingproductsofcombustion.

3.3.56Exhauster.See3.3.60.2,ExhausterFan.

3.3.57ExplosionVent.Aventtorelieveexplosionpressuresresultingfromignitionofamixtureofdecompositiongasesandair.[40,2007]

3.3.58ExplosiveMixture.Aflammableorcombustiblemixtureinaconfinedspace.

3.3.59FalseStart.Aconditionwherethecombustionturbinefailstocompleteitsignitionsequence(failuretostart)andcanresultinunburnedfuelsenteringtheHRSGenclosureorothercombustionturbineexhaustsystems.

3.3.60Fan.

3.3.60.1BoosterFan.Adeviceusedtoassistinthesupplyofairto,ortheremovaloffluegasproductsfrom,thecombustionchamberortosupplementdraftcapabilitytoachieverequiredflowthroughthecombustionairorfluegasflowpath.

3.3.60.2ExhausterFan.Afanlocatedatthepulverizeroutletusedtodrawtheprimaryairthroughthepulverizerandtodelivertheprimaryairfuelmixturetotheburner(s)orotherapparatus.

3.3.60.3ForcedDraft(FD)Fan.Adeviceusedtopressurizeandsupplyambientairtothecombustionchambertosupportcombustion.Inafluidizedbedboiler,FDfansgenerallyincludebothprimaryairandsecondaryairfans.

3.3.60.4InducedDraft(ID)Fan.AdeviceusedtoremovetheproductsofcombustionfromtheboilerorHRSGbyintroducinganegativepressuredifferential.

3.3.60.5PrimaryAirFan.Afanusedtosupplycoaltransportairtothepulverizerortotheburnerlinesofastoragesystem.

3.3.60.6SealAirFan.Afanusedtosupplysealingair.

3.3.61FanOverrideAction.Acontrolthat,upondetectionofsignificanterrorincombustionchamberpressure,actstorepositiontheinduceddraftfancontroldevice(s)inadirectionto

CopyrightNFPA

reducetheerror.

3.3.62FanTestBlockCapability.Thepointonthefanheadversusflowcharacteristiccurveatwhichthefanisselected.ThisisthecalculatedoperatingpointassociatedwiththemaximumcontinuousratingoftheboilerorHRSG,plustheheadandflowmargins.

3.3.63FeedForwardSignal.Asignalusedtoanticipateachangeinthemeasuredvariable.

3.3.64Flame.Abodyorstreamofgaseousmaterialinvolvedinthecombustionprocessandemittingradiantenergyatspecificwavelengthbandsdeterminedbythecombustionchemistryofthefuel.Inmostcases,someportionoftheemittedradiantenergyisvisibletothehumaneye.[72,2007]

3.3.65FlameDetector.Adevicethatsensesthepresenceorabsenceofflameandprovidesausablesignal.

3.3.65.1SelfCheckingFlameDetector.Aflamedetectorthatautomatically,andatregularintervals,teststheentiresensingandsignalprocessingsystemoftheflamedetector.

3.3.66FlameEnvelope.Theconfines(notnecessarilyvisible)ofanindependentprocessthatconvertsfuelandairintoproductsofcombustion.

3.3.67Fluidize.Tomaintainabedoffinelydividedsolidparticlesinamobilesuspensionbyblowingairorgasthroughthebedatsuchavelocitythattheparticlesseparateandbehavemuchlikeafluid.

3.3.68FluidizedBed.Abedofgranularparticlesmaintainedinamobilesuspensionbythevelocityofanupwardflowofairorgas.

3.3.69FlyCarbonReinjection.Inastokerfiredboiler,theprocessofremovingthecoarsecarbonbearingparticlesfromtheparticulatemattercarriedoverfromthefurnaceandreturningthecarbonaceousmaterialtothefurnacetobecombusted.

3.3.70Freeboard.Inafluidizedbedboiler,thespaceorvolumeabovetheuppersurfaceofthebubblingbedandbelowtheentrancetotheconvectionpass.

3.3.71FreshAirFiring.TheoperationofanHRSGwithairinsteadofcombustionturbineexhaust.

3.3.72Friability.Thetendencyofcoaltocrumbleorbreakintosmallpieces.

3.3.73Fuel.

3.3.73.1AuxiliaryFuel.Inafluidizedbedboiler,generallyagaseousorliquidfuelusedtowarmthebedmaterialsufficientlytoallowignitionofthemainfueluponinjectionintotheheatedbedmaterial.

3.3.73.2Coal.Asolidfuelclassifiedaslignite,subbituminous,bituminous,oranthraciteasdefinedbyASTMD388,StandardClassificationofCoalsbyRank.

3.3.73.2.1PulverizedCoal.Coalthatisreducedtoasizesuchthatatleast50percentcanpassthrougha200mesh(74microns)sieve.

3.3.73.3FuelOil(OilFuel).LiquidfuelsdefinedasGrades2,4,5,or6inASTMD396,

CopyrightNFPA

StandardSpecificationforFuelOils,orasGrade2GTinASTMD2880,StandardSpecificationforGasTurbineFuelOils.

3.3.73.4HoggedFuel.Woodrefusethathasbeenchippedorshreddedbyamachineknownasahog.

3.3.73.5JP4.Alight,volatilefuelwithaboilingpointbetweengasolineandlightdistillate.ItspropertiesaredefinedinMILT5624,TurbineFuel,Aviation,GradeJP4,JP5,andJP5/JP8ST,andaresimilartoASTMD1655,StandardSpecificationforAviationTurbineFuels(JetB),andASTMD2880,StandardSpecificationforGasTurbineFuelOils.

3.3.73.6Kerosene.Alight,highlyrefinedfuelthatisslightlymorevolatilethanNo.2fueloil.ItspropertiesaredefinedinASTMD396,StandardSpecificationforFuelOilsASTMD1655,StandardSpecificationforAviationTurbineFuelsorASTMD2880,StandardSpecificationforGasTurbineFuelOils.

3.3.73.7LPGas.Amaterialthatiscomposedpredominantlyofanyofthefollowinghydrocarbonsormixturesofthem:propane,propylene,nbutane,isobutane,andbutylenes.

3.3.73.8MainFuel.Inafluidizedbedboiler,gaseous,liquid,orsolidfuelintroducedintothebedafterthebedtemperaturehasreachedavaluesufficienttosupportitscombustionandthatisusedduringthenormaloperationoftheboiler.Mainfuelsnecessitatetheuseofthefluidizedhotbedastheirignitionsource.

3.3.73.9MunicipalSolidWaste(MSW).Solidwastematerialsconsistingofcommonlyoccurringresidentialandlightcommercialwaste.[850,2005]

3.3.73.10NaturalGas.Agaseousfueloccurringinnatureandconsistingmostlyofamixtureoforganiccompounds,normallymethane,ethane,propane,andbutane.Thecalorificvalueofnaturalgasesvariesbetweenabout26.1MJ/m3and55.9MJ/m3(700Btuperft3and1500Btuperft3),themajorityaveraging37.3MJ/m3(1000Btuperft3).

3.3.73.11PulverizedFuel.Solidfuelthatisreducedtoasizesuchthatatleast50percentwillpassthrougha200mesh(74microns)sieve.

3.3.73.12RefuseDerivedFuel(RDF).Asolidfuelpreparedfrommunicipalsolidwaste.Thewastematerialisusuallyrefinedbyshredding,airclassification,magneticseparation,orothermeans.Thefuelcanbepacked,chopped,pelletized,pulverized,orsubjecttoothermechanicaltreatment.

3.3.73.13SupplementaryFuel.Fuelburnedtosupplyadditionalheattothesteamgeneratorortosupportcombustion.

3.3.74FuelGas(GasFuel).GaseousfuelsdefinedasNaturalGas(see3.3.73.10)orLPGas(see3.3.73.7).

3.3.75FuelRich.Indicatesaratioofairtofuelsuppliedtoafurnacethatprovideslessthantheminimumexcessairneededforoptimumcombustionofthefuel.

3.3.76FuelTrip.Theautomaticshutoffofaspecificfuelastheresultofaninterlockoroperatoraction.

CopyrightNFPA

3.3.77Furnace.Theportionoftheboilerenclosurewithinwhichthecombustionprocesstakesplaceandwhereinheattransferoccurspredominantlybyradiation.

3.3.78Gate(forRawFuel)(SiloGateBunkerGate).Ashutoffgatebetweentherawfuelbunkerandtherawfuelfeeder.

3.3.79Grate.Thesurfaceonwhichfuelissupportedandburnedandthroughwhichairispassedforcombustion.

3.3.79.1BarsorKeysGrate.Thosepartsofthefuelsupportingsurfacearrangedtoadmitairforcombustion.

3.3.79.2HandFiredGrate.Agrateonwhichfuelisplacedmanually,usuallybymeansofashovel.

3.3.80Grindability.Thecharacteristicofsolidfuelthatindicatesitsrelativeeaseofpulverization,asdefinedbyASTMD409,StandardTestMethodforGrindabilityofCoalbytheHardgroveMachineMethod.

3.3.81Header.Apipeorductthroughwhichliquidorgasisconveyedandsuppliedtoorreceivedfrommultiplebranches.

3.3.82HeatRecoverySteamGenerator(HRSG).Aheatexchangerthatusesaseriesofheattransfersections(e.g.,superheater,evaporator,andeconomizer)positionedintheexhaustgasflowofacombustionturbinetorecoverheatandsupplyaratedsteamflowatarequiredtemperatureandpressure.

3.3.82.1HRSGEnclosure.Allductworkfromthecombustionturbineexhaustthroughthesteamgeneratortothestack,includinganybypassductconnection.

3.3.82.2HRSGPurge.See3.3.117.1,CombustionTurbinePurge 3.3.117.2,DuctBurner(HRSG)Purgeand3.3.118,PurgeRate.

3.3.82.3HRSGSystem.Theunitassemblyfromthecombustionturbineinlettothefluegasoutlettotheatmosphere.

3.3.83HoggedFuel.See3.3.73.4.

3.3.84Igniter.Apermanentlyinstalleddevicethatprovidesprovenignitionenergytolightoffthemainburner.

3.3.84.1Class1Igniter.Anigniterthatisappliedtoignitethefuelinputthroughtheburnerandtosupportignitionunderanyburnerlightofforoperatingconditions.Itslocationandcapacityaresuchthatitwillprovidesufficientignitionenergy,generallyinexcessof10percentoffullloadburnerinput,atitsassociatedburnertoraiseanycrediblecombinationofburnerinputsofbothfuelandairabovetheminimumignitiontemperature.

3.3.84.2Class2Igniter.Anigniterthatisappliedtoignitethefuelinputthroughtheburnerunderprescribedlightoffconditions.Itisalsousedtosupportignitionunderlowloadorcertainadverseoperatingconditions.Therangeofcapacityofsuchignitersisgenerally4percentto10percentoffullloadburnerfuelinput.

3.3.84.3Class3Igniter.Asmalligniterappliedparticularlytofuelgasandfueloilburnersto

CopyrightNFPA

ignitethefuelinputtotheburnerunderprescribedlightoffconditions.Thecapacityofsuchignitersgenerallydoesnotexceed4percentofthefullloadburnerfuelinput.

3.3.84.4Class3SpecialIgniter.AspecialClass3highenergyelectricalignitercapableofdirectlyignitingthemainburnerfuel.

3.3.85InertGas.Anygasthatisnonflammable,chemicallyinactive,noncontaminatingfortheuseintended,andoxygendeficienttotheextentrequired.[69,2002]

3.3.86InitialOperation.Thefirstcoordinatedoperationoftheunit.

3.3.87Interlock.Adevice,oranarrangementofdevices,inwhichtheoperationofonepartoronemechanismofthedeviceorarrangementcontrolstheoperationofanotherpartofanothermechanism.

3.3.88JP4.See3.3.73.5.

3.3.89Kerosene.See3.3.73.6.

3.3.90Lance.Adevice,withoutitsownairsupply,thatprovidesfuelinputdirectlyintoafluidizedbed.

3.3.91LedgePlate.Aformofplatethatisadjacentto,andoverlaps,theedgeofastoker.

3.3.92LightOffTimeLimitTimer.Adevicethatisusedonsupervisedmanualburnermanagementsystemsandlimitstheallowabletimebetweencompletionofpurgeandlightoff.

3.3.93LockHopper.Afeedingdevicethatincorporatesadoublepressureseal,thusenablingsolidstobefedintoasystemwithahigherpressurethanthepressureexistinginthesolid'sstoragearea.Also,aletdowndevicethatincorporatesadoublepressureseal,thusenablingsolidstobewithdrawnfromasystemwithahigherpressurethanthatexistingdownstreamofthelockhopper.

3.3.94LogicSystem.Thedecisionmakingandtranslationelementsoftheburnermanagementsystem.Alogicsystemprovidesoutputsinaparticularsequenceinresponsetoexternalinputsandinternallogic.Logicsystemsarecomprisedofthefollowing:(1)hardwiredsystemsindividualdevicesandinterconnectingwiringand(2)microprocessorbasedsystems(a)computerhardware,powersupplies,I/Odevices,andtheinterconnectionsamongthemand(b)operatingsystemandlogicsoftware.

3.3.95LowFire.Theminimumfireratethatresultsinstablecombustion.

3.3.96LPGas.See3.3.73.7.

3.3.97MainFuelTemperaturePermit.Theminimumfluidizedbedtemperatureatwhichthemainfuelcanbeintroducedwithresultingstablecombustion.

3.3.98*MasterFuelTrip.Aneventresultingintherapidshutoffofallfuel,includingignitersforHRSGs,aneventresultingintherapidshutoffofallfueltotheductburners,includingigniters.

3.3.99MasterFuelTripRelay.Anelectromechanicalrelay(s)utilizedtotripallrequired

CopyrightNFPA

equipmentsimultaneouslywhenamasterfueltripisinitiated.

3.3.100MinimumFluidizationVelocity.Inafluidizedbed,thelowestvelocitysufficienttocauseincipientfluidization.

3.3.101Monitor.Tosenseandindicateaconditionwithoutinitiatingautomaticcorrectiveaction.

3.3.102NaturalGas.See3.3.73.10.

3.3.103Oil.See3.3.73.3,FuelOil(OilFuel).

3.3.104OpenFlowPath.AcontinuouspathformovementofanairstreamfromtheforceddraftfaninlettothestackinanHRSGorothercombustionturbineexhaustsystem,acontinuouspathformovementofanairstreamthroughtheHRSGsystemorothercombustionturbineexhaustsystems.

3.3.105OpenRegisterLightOffProcedure.Aprocedureforpurgingandlightingoffaboilerunderspecified,controlledconditions.

3.3.106OperatingRange.Therangebetweenthemaximumfuelinputandminimumfuelinputwithinwhichtheburnerflamecanbemaintainedinacontinuousandstablemanner.

3.3.107OverfireAirPort.Anopeninginafurnacewalltoenabletheintroductionofanoverfireairstream.

3.3.108PartialLossofFlame.Lossofflameatanyoftheseparateflameenvelopesorburnerswhileflameismaintainedatanyoftheotherflameenvelopesorburners.

3.3.109PositiveMeans.Thephysicalmethodsofsatisfyingarequirement.

3.3.110Postpurge.Apurgeperformedaftertheburner(s)isshutdown.

3.3.111Pressure/AirLock.Adevicefortransferringpulverizedfuelbetweenzonesofdifferentpressurewithoutpermittingappreciableflowofairorgasineitherdirection.

3.3.112PrimaryAirFan(PulverizerAirFan).See3.3.60.5,PrimaryAirFan.

3.3.113Prove.Toestablishbymeasurementortesttheexistenceofaspecifiedconditionsuchasflame,level,flow,pressure,orposition.

3.3.114PulverizedFuel.See3.3.73.11.

3.3.115PulverizedFuelPump.Adeviceorsystemfortransportingfuelmechanicallyorpneumaticallybyutilizingminimumairflow.

3.3.116Pulverizer.Amachineforreducingtheparticlesizeofasolidfuelsothatitburnsinsuspension.

3.3.117Purge.Aflowofairoraninertmediumataratethatwilleffectivelyremoveanygaseousorsuspendedcombustiblesandreplacethemwiththepurgingmedium.

3.3.117.1CombustionTurbinePurge.AflowofairatpurgeratethroughthecombustionturbineandtheappropriateportionoftheHRSGenclosureorothercombustionturbineexhaustsystemsforanumberofvolumechangessufficienttoeffectivelyremoveany gaseous

CopyrightNFPA

orsuspendedcombustiblesandreplacethemwiththeair.

3.3.117.2DuctBurner(HRSG)Purge.AflowofcombustionturbineexhaustgasorairatpurgeratethroughtheHRSGenclosureforanumberofvolumechangessufficienttoeffectivelyremoveanygaseousorsuspendedcombustiblesandreplacethemwiththepurgingmedium.

3.3.118PurgeRate.Aconstantflowofpurgingmediumatvelocitysufficienttoachieveapurge.

3.3.119RawFuelFeeder.Adeviceforsupplyingacontrolledamountofrawfuel.

3.3.120Reburn.TheprocessofadmittingfueldownstreamofthemainburnerstocreateafuelrichzonewherechemicalreactionsreduceNOxtomolecularnitrogen.

3.3.121ReburnInjector.AdevicethatintroducesfuelwithoutcombustionairintoafurnaceforthepurposeofreducingNOxemissionsfromthefurnace.

3.3.122Recirculation(SolidsorRecycle).Thereintroductionofsolidmaterialextractedfromtheproductsofcombustionintoafluidizedbed.

3.3.123Recycle.Asingleburnerboilerstartupthatisinitiatedbysteampressureorwatertemperaturefollowinganormalshutdown.

3.3.124RecycleRate.Inafluidizedbed,therateatwhichamassofmaterialisreinjectedintothebed.Thisvalueisoftenexpressedastheratiooftheamountbeingreinjectedtothetotalamountbeingelutriatedfromthefluidizedbed.

3.3.125RecycleRatio.Inafluidizedbed,themassofmaterialbeingreinjectedintothebeddividedbythemassoffuelbeingfedintothebed.

3.3.126RefuseDerivedFuel(RDF).See3.3.73.12.

3.3.127Register(BurnerAir).Asetofdampersforaburner,orairsupplysystemtoaparticularburner,usedtodistributethecombustionairadmittedtothecombustionchamber.Frequentlycontrolsthedirectionandvelocityoftheairstreamforefficientmixingwiththeincomingfuel.

3.3.128Reinjection.Inafluidizedbedboiler,thereturnorrecyclingofmaterialremovedorcarriedfromthefurnacebacktothefurnace.Alsoreferstoflyashcollectedandreturnedtothefurnaceorcombustionchamber,sometimesexpressedasapercentofthetotalcollected.

3.3.129RemoteOperation.Controlfromalocationremovedfromthecombustionarea.

3.3.130Repair.Aprocessthatreturnsthecombustionsystemorsubsystemtoitsoriginaldesignspecificationsorcriteria.

3.3.131Repeatability.Theabilityofadevicetomaintainaconstantsetpointcharacteristic.

3.3.132Restart.Amanuallyinitiatedstartup.

3.3.133Retort.Atroughorchannelinanunderfeedstoker,extendingwithinthefurnace,throughwhichfuelisforcedupwardintothefuelbed.

CopyrightNFPA

3.3.134SafetyShutdownTripRelay.See3.3.99,MasterFuelTripRelay.

3.3.135Scavenging.Theprocedurebywhichliquidfuelleftinaburnerorigniterafterashutdownisclearedbyadmittingsteamorairthroughtheburnerpassages,typicallythroughadedicatedscavengingmediumvalve.

3.3.136SelectiveCatalyticReduction(SCR).AmethodofreducingNOxinfluegas.

3.3.137Semifluidized.Inafluidizedbedboiler,thestateinwhichauniformflowofairthatislessthanthatnecessarytofluidizethebedisadmittedandisfoundtobesufficienttoadequatelyremovegaseouscombustibles.

3.3.138ServiceConnection.Apointatwhichfuel,anatomizingmedium,orpowerisconnectedtothefiringequipmentorcontrolleddevices.

3.3.139SetPoint.Apredeterminedvaluetowhichadeviceorsystemisadjustedandatwhichitperformsitsintendedfunction.

3.3.140Shutdown.

3.3.140.1EmergencyShutdown(HRSGorothercombustionturbineexhaustsystems).Aneventresultingintherapidshutoffofallfueltothecombustionturbinealongwithamasterfueltrip.

3.3.140.2NormalShutdown.Stoppingburneroperationbyshuttingoffallfuelandignitionenergytothecombustionequipment.

3.3.140.3SafetyShutdown(SingleBurnerBoiler).Stoppingburneroperationbyshuttingoffallfuelandignitionenergytothefurnace.

3.3.141SideAirAdmission.Admissionofairtotheundersideofagratefromthesidesofachainortravelinggratestoker.

3.3.142SootBlower.Amechanicaldeviceforintroducingsteam,air,orwatertocleanheatabsorbingsurfaces.

3.3.143Sorbent.Inafluidizedbedboiler,aconstituentthatreactswithandcapturesapollutantor,moregenerally,aconstituentthatreactswithandcapturesanotherconstituent.

3.3.144SpentBedMaterial.Inafluidizedbedboiler,materialremovedfromthebedgenerallycomprisedofreactedsorbent,calcinedlimestone,ash,andsolid,unburnedcombustibles.Forsomeapplications,thespentbedmaterialmightalsocontainsomeinertmaterial,suchassand.

3.3.145StableBed.Inafluidizedbedboiler,abedofgranularmaterialthatmaintainssustainedcombustionatadesiredtemperature.

3.3.146StableFlame.Aflameenvelopethatretainsitscontinuitythroughoutthemaximumrateofchangewithintheoperatingrangeoftheboiler,burner,orHRSG.

3.3.147SteamGenerator.Apressurevesselinwhichwaterisconvertedtosteamorsteamissuperheated,orinwhichanycombinationthereoftakesplace.

CopyrightNFPA

3.3.148SteamGeneratorCapacity.Themanufacturer'sstatedsteamoutputrateoveraperiodoftimeforwhichthesteamgeneratorisdesignedtooperate.

3.3.149SteamGeneratorEnclosure.Thephysicalboundaryforallsteamgeneratorpressurepartsandthecombustionprocess.

3.3.150Stoker.

3.3.150.1ChainGrateStoker.Astokerthathasamovingendlesschainasagratesurface,ontowhichcoalisfeddirectlyfromahopper.

3.3.150.2DumpGrateStoker.Astokerequippedwithmovableashtrays,orgrates,bymeansofwhichtheashisdischargedatanydesirableinterval.

3.3.150.3ForcedDraftStoker.Astokerinwhichtheflowofairthroughthegrateiscausedbyapressureproducedbymechanicalmeans.

3.3.150.4FrontDischargeStoker.Astokersoarrangedthatrefuseisdischargedfromthegratesurfaceatthesameendasthecoalfeed.

3.3.150.5MechanicalStoker.Adeviceconsistingofamechanicallyoperatedfuelfeedingmechanismandagrate,usedforthepurposeoffeedingsolidfuelintoafurnace,distributingitoveragrate,admittingairtothefuelforthepurposeofcombustion,andprovidingameansforremovalordischargeofrefuse.

3.3.150.6MultipleRetortStoker.Anunderfeedstokerconsistingoftwoormoreretorts,parallelandadjacenttoeachother,butseparatedbyalineoftuyeres,andarrangedsothattherefuseisdischargedattheendsoftheretorts.

3.3.150.7OverfeedStoker.Astokerinwhichfuelisfedontogratesabovethepointofairadmissiontothefuelbed.Overfeedstokergratesincludethefollowing:(1)FrontFeed,InclinedGrateFuelisfedfromthefrontontoagrateinclineddownwardtowardtherearofthestoker(2)ChainorTravelingGrateAmovingendlessgratethatconveysfuelintoandthroughthefurnacewhereitisburned,afterwhichitdischargestherefuse(3)VibratingGrateAninclinedvibratinggrateinwhichfuelisconveyedintoandthroughthefurnacewhereitisburned,afterwhichitdischargestherefuse.

3.3.150.8RearDischargeStoker.Astokersoarrangedthatashisdischargedfromthegratesurfaceattheendoppositethesolidfuel.

3.3.150.9ReciprocatingGrateStoker.Agrateelementthathasreciprocatingmotion,usuallyforthepurposeoffuelagitationorashremoval.

3.3.150.10SideDumpStoker.Astokersoarrangedthatrefuseisdischargedfromadumpplateatthesideofthestoker.

3.3.150.11SingleRetortStoker.Anunderfeedstokerusingoneretortonlyintheassemblyofacompletestoker.

3.3.150.12SpreaderStoker.Astokerthatdistributesfuelintothefurnacefromalocationabovethefuelbedwithaportionofthefuelburnedinsuspensionandaportiononthegrates.Spreaderstokergratesincludethefollowing:(1)StationaryGrateAgratein

CopyrightNFPA

whichfuelisfedontoafixedpositiongrate(2)DumpGrateAgrateinwhichfuelisfedontoanonmovinggratethatisarrangedtoallowintermittentdischargeofrefusethroughtiltingactionofthegratebars(3)ContinuousDischargeorTravelingGrateAgratethatcontinuouslydischargestherefusefromtheendafterburningthefuel.

3.3.150.13TravelingGrateStoker.Astokersimilartoachaingratestokerwiththeexceptionthatthegrateisseparatefrombutissupportedonanddrivenbychains.

3.3.150.14UnderfeedStoker.Astokerinwhichfuelisintroducedthroughretortsatalevelbelowthelocationofairadmissiontothefuelbed.Underfeedstokersaredividedintothreegeneralclasses.

3.3.150.14.1ContinuousAshDischargeUnderfeedStoker.Astokerinwhichtherefuseisdischargedcontinuouslyfromthenormallystationarystokerashtraytotheashpit,withouttheuseofmechanicalmeansotherthanthenormalactionofthecoalfeedingandagitatingmechanism.

3.3.150.14.2RearDischargeUnderfeedStoker.Astokerhavingagratecomposedoftransverselyspacedunderfeedretortsthatfeedanddistributesolidfueltointermediaterowsoftuyeresthroughwhichairisadmittedforcombustion.Theashisdischargedfromthestokeracrosstherearend.

3.3.150.14.3SideAshDischargeUnderfeedStoker.Astokerhavingoneormoreretortsthatfeedanddistributefuelontosidetuyeresoragratethroughwhichairisadmittedforcombustionandoverwhichtheashisdischargedatthesideparalleltotheretorts.

3.3.150.15WaterCooledStoker.Astokerhavingtubesinornearthegratesurfacethroughwhichwaterispassedforcoolingthegrates.

3.3.151StokerGate.Anelementofastokerplacedatthepointofentranceoffuelintothefurnaceandbymeansofwhichthedepthoffuelonthestokergrateiscontrolled.Itisgenerallyusedinconnectionwithchainortravelinggratestokersandhastheformofaguillotine.

3.3.152Sulfation.Theexothermicchemicalreactionthattakesplacewhencalciumoxideuniteswithoxygenandsulfurdioxidetoformcalciumsulfate.

3.3.153SulfurCapture.Themolarfractionofsulfurinthefuelinputthatiscapturedbycalciumoxidetoformcalciumsulfate.

3.3.154SulfurReacted.Inafluidizedbed,thefractionofthetotalsulfurinthefuelfedtothebedthatisconvertedtosulfurdioxideorcalciumsulfate.

3.3.155SulfurRetention.Themolarratioofthetotalsulfurinthefuelminusthesulfurleavingtheunitassulfurdioxidetothetotalsulfurinthefuel.

3.3.156Supervise.Tosenseandindicateaconditionrequiringattentionandtoautomaticallyinitiatecorrectiveaction.

3.3.157SupplementaryFiring.TheprovisionofductburnersinanHRSGtoincreasethetemperatureofthecombustionturbineexhaustgases.

CopyrightNFPA

3.3.158Switch.

3.3.158.1NormalShutdown,HighSteamPressureSwitch.Apressureactuateddevicethatisarrangedtoeffectanormalburnershutdownwhenthesteampressureexceedsapresetpressure.

3.3.158.2NormalShutdown,HighWaterTemperatureSwitch.Atemperatureactuateddevicethatisarrangedtoeffectanormalburnershutdownwhenthewatertemperatureexceedsapresettemperature.

3.3.158.3ProcessMonitoring,HighOilTemperatureSwitch.Atemperatureactuateddevicethatinitiatesasignalwhenoiltemperaturerisesabovethelimitsthatarerequiredtomaintaintheviscosityrangerecommendedbytheburnermanufacturer.

3.3.158.4ProcessMonitoring,LowOilTemperatureSwitch.Atemperatureactuateddevicethatinitiatesasignalwhentheoiltemperaturefallsbelowthelimitsthatarerequiredtomaintaintheviscosityrangerecommendedbytheburnermanufacturer.

3.3.158.5ProofofClosureSwitch.Adevicethatprovidesfeedbackthatapieceofequipmentisintheclosedposition.ForChapter5,SingleBurnerBoilers,whenreferringtosafetyshutoffvalves,itisanonfieldadjustableswitchinstalledbythevalvemanufacturerandthatactivatesonlyafterthevalveisfullyclosed.

3.3.158.6SafetyShutdown,ExcessiveSteamPressureSwitch.Apressureactuateddevicethatisarrangedtoeffectasafetyshutdownoftheburnerwhenthesteampressureexceedsapresetpressure.

3.3.158.7SafetyShutdown,ExcessiveWaterTemperatureSwitch.Atemperatureactuateddevicethatisarrangedtoeffectasafetyshutdownoftheburnerwhenthewatertemperatureexceedsapresettemperature.

3.3.158.8SafetyShutdown,HighGasPressureSwitch.Apressureactuateddevicethatisarrangedtoeffectasafetyshutdownortopreventstartingwhenthegaspressureexceedsthepresetvalue.

3.3.158.9SafetyShutdown,LowGasPressureSwitch.Apressureactuateddevicethatisarrangedtoeffectasafetyshutdownortopreventstartingwhenthegaspressurefallsbelowthepresetvalue.

3.3.158.10SafetyShutdown,LowOilPressureSwitch.Apressureactuateddevicethatisarrangedtoeffectasafetyshutdownortopreventstartingwhentheoilpressurefallsbelowthepresetvalue.

3.3.158.11SafetyShutdown,LowWaterCutoutAuxiliarySwitch.Onsingleburnerboilers,adevicethatisarrangedtoeffectasafetyshutdownoftheburnerwhenthewaterlevelintheboilerfallstoapredeterminedlowlevel.

3.3.158.12SafetyShutdown,LowWaterCutoutSwitch.AdevicethatisarrangedtoeffectasafetyshutdownormasterfueltripwhenthewaterlevelintheboilerorHRSGfallstoapredeterminedlowlevel.

3.3.159TrialforIgnitionPeriod(Igniter).Theintervaloftimeduringlightoffinwhicha

CopyrightNFPA

safetycontrolcircuitpermitstheigniterfuelsafetyshutoffvalve(s)tobeopenedbeforetheflamedetectionsystemisrequiredtosupervisetheigniterflame.

3.3.160TrialforIgnitionPeriod(MainBurner).Theintervaloftimeduringlightoffinwhichasafetycontrolcircuitpermitsthemainburnerfuelsafetyshutoffvalve(s)tobeopenedbeforetheflamedetectionsystemisrequiredtosupervisethemainburnerflameonly.

3.3.161Tuyeres.Formsofgrates,locatedadjacenttoaretort,feeders,orgratesealsthroughwhichairisintroduced.

3.3.162UnattendedOperation.Ameansofoperationwheretheoperatorisnotinviewofoperatinginstrumentation(localorremote),norinapositiontooperatecontrolsystems.

3.3.163Unit.Thecombinedspacesofthefurnaceandtheassociatedboilerpasses,ducts,andfansthatconveythegasesofcombustiontothestackforHRSGs,thecombinedspacesofthecombustionturbine,theHRSG,andtheassociatedductsthatconveytheairandcombustiongasesfromtheairintaketothestackforothercombustionturbineexhaustsystems,thecombinedspacesofthecombustionturbine,andtheassociatedductsthatconveytheairandcombustiongasesfromtheairintaketothestack.

3.3.164Valve.

3.3.164.1BarrierValve.Avalve,notnecessarilydusttight,usedtoinhibithotgasesfromtravelingbackintoanysystemcomponentopenforinspectionormaintenance.

3.3.164.2BurnerShutoffValve.Inapulverizedfuelsystem,avalvethatisinstalledinthefuellinebetweenthepulverizerandtheburner.

3.3.164.3ChargingValve.Inagaseousorliquidfuelsystem,asmallvalvebypassingthemainsafetyshutoffvalveusedforpurgingandchargingthefuelheadersandpipingandfortestingforleaks.

3.3.164.4CheckValve.Avalvethatallowsflowinonedirectiononly.[13D,2007]

3.3.164.5DusttightValve.Inapulverizedfuelsystem,atightseatingvalveinstalledinthefuelsupplypipetotheburnertoalloworstopflow.

3.3.164.6FlowControlValve.Avalvecapableofregulatingquantityofthroughputtoacontrolledrange.

3.3.164.7SafetyShutoffValve(SafetyTripValve).Afastclosingvalvethatautomaticallyshutsoffthegaseousorliquidfuelsupplyinresponsetoanormal,emergency,orsafetyshutdownsignal.

3.3.164.8SupervisoryShutoffValve.Inagaseousorliquidfuelsystem,amanuallyoperatedshutoffvalvewithameanstoprovideavalveclosedpositionsignal.

3.3.164.9VentControlValve.Acontrollablevalveforregulatingtheflowofventedairorgasfromthesystem.

3.3.164.10VentValve.Avalveusedtoallowventingofairorgasfromthesystemtotheatmosphere.

CopyrightNFPA

3.3.165ValveProvingSystem.Inagaseousorliquidfuelsystem,asystemthatprovestheleaktightnessofallsafetyshutoffvalvesandpreventsmainburnerorigniterlightoffifthetestisnotsatisfied.

3.3.166VolatileMatter.Theportionofmass,exceptwatervapor,thatisdrivenoffinagaseousformwhensolidfuelsareheated.

3.3.167WatchDogTimer.Atimerexternaltoamicroprocessorbasedcontrolthatisusedtocomparethemicroprocessorcycletimingagainstitselfandthatfailssafelyifthemicroprocessortimingstopsorexceedsthewatchdogtimeinterval.

Chapter4FundamentalsofBoilerCombustionSystems

4.1*Manufacture,Design,andEngineering.

4.1.1 Theownerortheowner'srepresentativeshall,incooperationwiththemanufacturer,ensurethattheunitisnotdeficientinapparatusthatisnecessaryforoperationwithrespecttopressureparts,fuelburningequipment,airandfuelmetering,lightoff,andmaintenanceofstableflame.

4.1.2 Allfuelsystemsshallincludeprovisionstopreventforeignsubstancesfrominterferingwiththefuelsupply.

4.1.3* Anevaluationshallbemadetodeterminetheoptimumintegrationofmanualandautomaticsafetyfeatures.

4.1.4 Althoughthiscoderequiresaminimumdegreeofautomation,morecomplexplants,plantswithincreasedautomation,andplantsdesignedforremoteoperationshallrequireadditionalprovisionsforthefollowing:

(1) Informationregardingsignificantoperatingeventsthatallowtheoperatortomakearapidevaluationoftheoperatingsituation

(2) Continuousandusabledisplaysofvariablesthatallowtheoperatortoavoidhazardousconditions

(3) Inservicemaintenanceandcheckingofsystemfunctionswithoutimpairmentofthereliabilityoftheoverallcontrolsystem

(4) Anenvironmentconducivetotimelyandcorrectdecisionsandactions

4.1.5 Theburnerorfuelfeedpipingandequipmentshallbedesignedandconstructedtopreventtheformationofhazardousconcentrationsofcombustiblegasesthatexistundernormaloperatingconditions.

4.2InstallationandCommissioning.

4.2.1 Theboiler,heatrecoverysteamgenerator(HRSG),combustionturbineexhaustsystem,orpulverizedfuelsystemshallnotbereleasedforoperationbeforetheinstallationandcheckoutoftherequiredsafeguardsandinstrumentationsystemhavebeensuccessfully

CopyrightNFPA

completed.

4.2.2 Thepartyresponsiblefortheerectionandinstallationoftheequipmentshallensurethatallpertinentapparatusisinstalledandconnectedinaccordancewiththesystemdesign.

4.2.3 Theownerorowner'srepresentative,theengineeringconsultant,theequipmentmanufacturer,andtheoperatingcompanyshallprohibitoperationuntilthesafeguardshavebeentestedforcorrectoperationasasystem.

4.2.3.1 Iftemporaryinterlocksandinstrumentationarenecessarytomeettheserequirements,anysuchtemporarysystemshallbereviewedbythepurchaser,theengineeringconsultant,theequipmentmanufacturer,andtheoperatingcompany,andagreementshallbereachedonthesystem'sabilitytoprotectequipmentandpersonnelinadvanceofstartup.

4.2.3.2 Alltemporarymodificationsshallbedocumented,andpermanentresolutionsshallbeaccomplishedpriortocommercialoperation.

4.2.4 Thesafetyinterlocksystemandprotectivedevicesshallbetestedjointlybytheorganizationresponsibleforthesystemdesignandbythosewhooperateandmaintainsuchasystemanddevices.

4.2.5 Afterinstallationbutbeforeinitialoperation,coordinatedtestsofallsystemsshallbeaccomplished.

4.2.6 Documentationoftheplantequipment,thesystem,andmaintenanceactivitiesshallbeupdatedtoreflectchangesinthestatusofequipmentandoperatingprocedures.

4.3CoordinationofDesign,Construction,andOperation.

4.3.1* Duringtheplanningandengineeringphasesofplantconstruction,thedesignshallbecoordinatedwithoperatingpersonnel.

4.3.2* Theintegrationofthevariouscomponents,includingboilerorHRSG,burner,fuelandairsupplyequipment,controls,interlocksandsafetydevices,operatorandmaintenancefunctions,andcommunicationandtraining,shallbetheresponsibilityof theownerandtheoperatingcompany.

4.4Maintenance,Inspection,Training,andSafety.

4.4.1MaintenanceandEquipmentInspection.SeealsoAnnex J.

4.4.1.1* Aprogramshallbeprovidedforinspectionandmaintenanceofequipmentatintervalsconsistentwiththetypeofequipmentused,servicerequirements,andmanufacturers'recommendations.

4.4.1.2 Asaminimum,themaintenanceprogramshallincludethefollowing:

(1) Inserviceinspectionstoidentifyconditionsthatneedcorrectiveaction

(2) Welldefinedplanningformakingrepairsormodificationsusingqualifiedpersonnelandtoolsandinstrumentsdesignedforthework

(3) Equipmenthistoryandrecordofdatesofservice,conditionsfound,maintenance

CopyrightNFPA

performed,andchangesmade

(4) Writtencomprehensivemaintenanceproceduresincorporatingthemanufacturer'sinstructionstodefinethetasksandskillsrequired

(5) Nondestructiveexaminationrequirementstasksneedingspecialtoolsspecialenvironmentalfactorssuchastemperaturelimitations,dusts,contaminatedoroxygendeficientatmospheres,andlimitedaccessorconfinedspacerestrictions

(6) Equipmentconditionassessmentbeforeandaftermaintenance

(7) Supplyofwellmaintainedsparepartstoperformrequiredmaintenance

(8) Housekeepingessentialforsafeoperationandpreventionoffiresorexplosionsthatincludesthefollowing:

(a) Provisionsforcleaningofhorizontalledgesorsurfacesofbuildingsandequipmenttopreventtheaccumulationofdustdepositsgreaterthantheminimumrequiredtocreateanexplosionhazard

(b) Waterwashingorvacuumcleaningmethodstoreducethepossibilityofcreatingdustclouds

(c) Prohibitionoftheuseofcompressedairforcleaning

4.4.1.3* Operation,setpoints,andadjustmentsshallbeverifiedbytestingatspecifiedintervals,andtheresultsshallbedocumented.

4.4.1.4 Defectsshallbereportedandcorrected,andthechangesorrepairsdocumented.

4.4.1.5 Systemconfiguration,includinglogic,setpoints,andsensinghardware,shallnotbechangedwithoutdetailedengineeringreviewanddocumentation.

4.4.1.6 Systemoperationshallbetestedandverifiedforcompliancewiththedesigncriteriawheneveracontrollerisreplaced,repaired,reprogrammed,orupdatedbeforereturningittoservice.

4.4.1.7 Whenaunitthatfiresliquidfuelisoutofserviceandavailableforinspection,personnelshallcheckforanyaccumulationofunburnedfuelintheboilerorHRSGenclosure,especiallyinthefintubeareaofanHRSG.

4.4.2Training.

4.4.2.1OperatorTraining.

4.4.2.1.1* Theownerortheowner'srepresentativeshallberesponsibleforestablishingaformaltrainingprogramthatisconsistentwiththetypeofequipmentandhazardsinvolvedtopreparepersonneltooperateequipment.

4.4.2.1.2 Operatingproceduresshallbeestablishedthatcovernormalandemergencyconditions.

4.4.2.1.2.1 Startup,shutdown,andlockoutproceduresshallallbecoveredindetail.

4.4.2.1.2.2 Wheredifferentmodesofoperationarepossible,proceduresshallbeprepared

CopyrightNFPA

foreachoperatingmode.

4.4.2.1.2.3 Proceduresalsoshallbepreparedforswitchingfromonemodetoanother.

4.4.2.1.3 Theownerorowner'srepresentativeshallverifythatoperatorsaretrainedandcompetenttooperatetheequipmentunderallconditionspriortotheiroperationofsuchequipment.

4.4.2.1.4 Theownerorowner'srepresentativeshallberesponsibleforretrainingoperators,includingreviewingtheircompetence,atintervalsdeterminedbytheowner.

4.4.2.1.5 Thetrainingprogramandoperatingandmaintenancemanualsshallbekeptcurrentwithchangesinequipmentandoperatingproceduresandshallbeavailableforreferenceanduseatalltimes.

4.4.2.1.6 Operatingproceduresshallbedirectlyapplicabletotheequipmentinvolvedandshallbeconsistentwithsafetyrequirementsandthemanufacturer'srecommendations.

4.4.2.2MaintenanceTraining.

4.4.2.2.1* Theownerorowner'srepresentativeshallberesponsibleforestablishingaformalandongoingprogramthatisconsistentwiththeequipmentandhazardsinvolved,fortrainingmaintenancepersonneltoperformallrequiredmaintenancetasks.

4.4.2.2.2 Maintenanceproceduresandtheirassociatedtrainingprogramsshallbeestablishedtocoverroutineandspecialtechniques.

4.4.2.2.3 Environmentalfactorssuchastemperature,dusts,contaminatedoroxygendeficientatmospheres,internalpressures,andlimitedaccessorconfinedspacerequirementsshallbeincludedinthemaintenanceprocedures.

4.4.2.2.4 Maintenanceproceduresshallbeconsistentwithsafetyrequirementsandthemanufacturer'srecommendationsandshallbekeptcurrentwithchangesinequipmentandpersonnel.

4.5BasicOperatingRequirements.

4.5.1 Operatingprocedureswithaminimumnumberofmanualoperationsshallbeestablished.

4.5.2 Standardoperatingproceduresthatresultinwelldefinedandcontrolledoperationsshallbeestablished.

4.5.3 Interlocksshallbeprovidedtoensurecorrectoperatingsequencesandtointerruptsequenceswhenconditionsarenotcorrectforcontinuation.

4.5.4 Nointerlocksshallbebypassedduringstartuporoperationoftheunitunlessthebypassistaggedandisgovernedbyoperatingprocedures.

4.5.5 Purgeandstartupprocedureswithnecessaryinterlocksshallbeestablished.

4.5.6 Writtenoperatingproceduresanddetailedchecklistsforoperatorguidanceshallbeprovidedforachievingallautomaticandmanualoperatingfunctions.

CopyrightNFPA

4.6EquipmentRequirements.

4.6.1*StructuralDesign.Thefurnaceshallbecapableofwithstandingtransientdesignpressuresandnormaloperatingpressureswithoutpermanentdeformationduetoyieldorbucklingofanysupportmember.Transientpressurestobeconsideredshallincludebutshallnotnecessarilybelimitedtomisoperationoffansordampersandamasterfueltripwhileoperatingatmaximumdesignload.Refertoindividualchaptersforadditionalguidance.

4.6.2FunctionalRequirementsofFuelBurningSystem.SeealsoAnnex K.

4.6.2.1Function.Thefuelburningsystemshallfunctiontoconvertcontinuouslyanyignitibleinputintounreactiveproductsofcombustionatthesameratethatthefuel(s)andairreactantsenterthecombustionchamber.

4.6.2.2Compatibility.Thefuelburningsystemshallbesizedtomeettheoperatingrequirementsoftheunit,compatiblewithothercomponentsystems,andcapableofbeingcontrolledforthefulloperatingrangeoftheunit.

4.6.2.3SystemRequirements.

4.6.2.3.1 Thefuelburningsystemshallprovidemeansforstartup,operation,andshutdownofthecombustionprocess,includingopeningsandconfigurationsinthecomponentassembliestoallowobservation,measurement,andcontrolofthecombustionprocess.

4.6.2.3.2 ThefuelburningsystemshallconsistoftheboilerorHRSGenclosureandthefollowingsubsystems,asapplicable:airsupplies,fuelsupplies,mainfuelburning,ignition,andcombustionproductsremovalandreinjection.Eachshallbesizedandinterconnectedtomeettherequirementsin 4.6.2.3.2.1through 4.6.2.3.2.5.

4.6.2.3.2.1 TheboilerenclosureorHRSGenclosureshallmeettherequirementsin4.6.2.3.2.1(A)through 4.6.2.3.2.1(C).

(A) Theenclosureshallbesizedandarrangedwithrespecttothemainfuelburningsubsystemsothatstableflameismaintained.

(B) Theenclosureshallbefreefromdeadpocketswhenprescribedpurgeproceduresarefollowed.

(C) Observationportsshallbeprovidedtoallowvisualinspectionofthecombustionchamber,igniterandburnerflames(includingtheignitionzone),overfireairports,reburninjectors,andstokergrates.

4.6.2.3.2.2 Theairsupplysubsystemshallmeettherequirementsin 4.6.2.3.2.2(A)through4.6.2.3.2.2(D).

(A) Theairsupplyequipmentshallbesizedandarrangedtoensureacontinuousairflowforalloperatingconditionsontheunit.

(B)* Thearrangementofairinlets,ductwork,andairpreheatersshallbedesignedtominimizecontaminationoftheairsupplybyfluegas,water,fuel(s),andothermaterialsasaresultofeitherintentionaloraccidentaldischarges.

CopyrightNFPA

(C) Drainandaccessopeningsshallbeprovidedandshallbeaccessible.

(D) Theairsupplyequipmentshallbecapableofcontinuingtherequiredairflowduringanticipatedcombustionchamberpressurepulsations.

4.6.2.3.2.3 FuelsuppliesandmainfuelburningsubsystemsshallmeettheapplicablerequirementsinChapters5through 10forspecificsystems.

4.6.2.3.2.4* Theignitionsubsystemshallmeettherequirementsof 4.6.2.3.2.4(A)through4.6.2.3.2.4(M).

(A) Theignitionsubsystemshallbesizedandarrangedtoignitethemainburnerinputwithinthelimitationoftheigniterclassificationasfollows:

(1) Itshallbeverifiedthroughtestingthattheignitersfurnishedmeettherequirementsoftheclassspecifiedinthedesign.

(2) IgnitersshallbedesignatedasClass1,Class2,orClass3asdefinedin 3.3.84.1,3.3.84.2,and3.3.84.3andasverifiedbytest.

(B) Class1ignitersshallbepermittedtobeusedasClass2orClass3igniters.Class2ignitersshallbepermittedtobeusedasClass3igniters.

(C) WhereClass2ignitersareused,theburnershallbeoperatedundercontrolledconditionstolimitthepotentialforabnormaloperation,aswellastolimitthechargeoffuelintheeventthatignitiondoesnotoccurduringlightoff.

(D) Class2ignitersshallnotbeusedtoignitethemainfuelunderuncontrolledorabnormalconditions.

(E) WhereClass3ignitersareused,theignitershallbeturnedoffasapartoftheburnerlightoffprocedurewhenthetimetrialforignitionofthemainburnerhasexpired,toensurethatthemainflameisnotdependentonignitionsupportfromtheigniter.

(F) Class2ignitersshallnotbeusedtoextendtheturndownrangebutshallbepermittedtobeusedtosupportignitionunderlowloadoradverseoperatingconditions.

(G) Class3ignitersshallnotbeusedtosupportignitionortoextendtheburnerturndownrange.

(H) Class3specialignitersshallnotbeusedunlesssupervisionoftheindividualmainburnerflameisprovided.Class3specialignitersshallbepermittedtobeusedwithoutsupervisionoftheindividualmainburnerflamewhilethemainburnerisbeingscavenged.

(I)* WhereClass1andClass2ignitersareused,thetestsdescribedin 6.6.3.2.2,6.7.3.2.2,and6.8.3.2.2shallalsobeperformedwiththeignitionsubsysteminservicetoverifythattheignitersfurnishedmeettherequirementsoftheclassspecifiedinthedesign.

(J) Testsshallbeperformedtodeterminetransientlimitsintheignitionairandfuelsuppliesorinthemainairandfuelsuppliesthatdonotextinguishtheigniterflameorreducetheigniter'sabilitytoperformitsintendedfunctionoradverselyaffectotherburnersandignitersinoperation.

CopyrightNFPA

(K) Ignitersshallbepermanentlyinstalledunderthefollowingconditions:

(1) Theyshallbesupervisedtoverifythattherequirementsof 4.6.2.3.2.4(A)and4.6.2.3.2.4(B)aremet.

(2) Thissupervisionshallincludeignitercapacityandindividualigniterflamemonitoring.

(3) Thecapacityshallbemeasuredbyigniterheaderpressureasaminimum.

(4) Onsingleburnerboilers,ignitersshallnotrequiresupervisionofignitercapacity.

(L) Theignitionequipmentshallbelocatedinanenvironmentfreeofexcessiveheatandaccessibleformaintenance.

(M) Allignitersafetyshutoffvalvesshallbelocatedtominimizethevolumeoffuelthatisdownstreamofthevalveintheindividualigniterfuellinesorthatcouldflowbygravityintothecombustionchamberafteranemergencyshutdownoraburnershutdown.

4.6.2.3.2.5 Thecombustionproductsremovalsubsystemshallmeetthefollowingrequirements:

(1) Thefluegasducts,fans,andstackshallbesizedandarrangedtoremovetheproductsofcombustionatthesamerateatwhichtheyaregeneratedbythefuelburningprocessduringoperationoftheunit.

(2) Drainandaccessopeningsshallbeprovidedandshallbeaccessible.

(3) Thefluegasductsshallbedesignedsothattheydonotcontributetocombustionchamberpulsations.

(4) ComponentscommontomorethanoneboilerorHRSGshallnotlimittherateofremovalofproductsofcombustiongeneratedduringtheoperationofallboilersorHRSGs.

(5) Boilersthatshareacommoncomponentbetweenthefurnaceoutletandthestackshallhaveprovisionstobypassthecommoncomponentforunitpurge.

(6) Wherethecommoncomponentdoesnotcontainapossibleignitionsource,abypassshallnotberequired.

4.6.2.3.3MultipleBoilers.

4.6.2.3.3.1 Wheremultipleboilersaresu