WPC  JNbdMFj!pLeGKŽ^u(,ZTE$+,vl!/1Ma-A)7>7Mpዋlz.0Ӻd|^;_߭ Jqqe,Cc[z ?@bJCsw8"E/N]_=*m }M\G :MaB(z4B0!o%?8-gNOg!t!_*)pZAjMy̨s:%o#7@:8w4BB=v}\HiZeoXI?Ռ ;9ٝM9E2&>HL )=@$z#,]vqi7Qҟ87 =8,X ލ#r;IO$1w[1K̞j ` *" #w:HS̳k8lYU: %(. 0OE  0O5nE 04 B &CC w 4 <6X9`("Courier 10cpiX v '   X? ' xdE!?     EMCGD025  < EMCGUIDELINEDOCUMENT   L   PAGE  1    ? ' xdE!? ('2$  T!     )   X? ' xdE!?  Preparedby DanBivins ,EMC     D     EMCGD025   EMC,OAQPS,EPA  <      D     June21,1994  ? ' xdEr!?('2$  T!   3|x <6X9`("Courier 10cpiXx6X@;X@( T$   d  )   X? ' xdE!?  Preparedby DanBivins ,EMB     D     EMTICGD025   TechnicalSupportDivision,OAQPS,EPA D     June21,1994  ? ' xdEr!? z '   X? ' xdE!?     EMTICGD025  < EMTICGUIDELINEDOCUMENT   L   PAGE  1    ? ' xdE!? {$  T!   ,X    ? ' $xdE$!?  @..EMISSIONMEASUREMENTTECHNICALINFORMATIONCENTER@JJ"GUIDELINEDOCUMENT? ' $xdE$!?    DETERMINATIONOFTHEPRESENCEOFSTRATIFICATIONOFGASEOUSPOLLUTANTANDDILUENTEMISSIONSFORCONTINUOUSEMISSIONMONITORORREFERENCEMETHODRELATIVEACCURACYLOCATIONS  INTRODUCTION   F      TheCEMSlocationsinductworkclosetothegroundareusuallythemostaccessibleformaintenanceandrepairpurposes,butoftenprovideverydifficultsituationsintermsofrepresentativesampling.Becauseductworkisminimizedforefficiencyofspaceandcost,fewductlocationsprovideawellmixedconditiondesirableforCEMSinstallation.Frequently,bypassedgasismixedwithcleanedorscrubbedgasforreheatingpurposes,andtheresultissignificantstratificationofemissionswithintheductwork.Stratificationcanalsooccurduetopoorscrubberoperation,especiallythroughpluggingofgaspassagewaysandliquidslurryspraynozzles.Thislattertypeofstratificationismostdifficulttomeasureandisoftentemporallyvariable.Stratificationmaycauseapollutantordiluentmonitortofailtherelativeaccuracytestbecausethereferencemethodmaysamplebecollectedatanothernonstratifiedlocation. DISCUSSION  f   Ifstratificationissuspected,thefollowingproceduretolocateapointorpathofaverageemissionsformonitorlocationselectionissuggested.Forrectangularducts,locateatleastninesamplepointsinthecrosssectionsuchthatsamplepointsarethecentroidsofsimilarlyshaped,equalareadivisionsofthecrosssection.Measurethepollutantconcentrationand,ifapplicable,thediluentconcentrationateachpointusingappropriatereferencemethodsorotherappropriateinstrumentmethodsthatgiveresponsesrelativetopollutantconcentrations.Thencalculatethemeanvalueforallsamplepoints,andselectapoint,points,orpaththatprovidesavalueequivalenttothemean.Thesamplelocationshouldbewithintheinner50percentareaofthecrosssection.Forcircularducts,conducta12pointtraverse(i.e.,sixpointsoneachofthetwoperpendiculardiameters)locatingthesamplepointsasdescribedin40CFR60,AppendixA,Method1.Performthemeasurementsandcalculationsasdescribedabove,anddetermineapoint,points,orpaththatprovidesavalueequivalenttothemean.Thesamplelocationshouldbewithintheinner50percentareaofthecrosssection.Ifstratificationisexpectedatthereferencemethodlocationforrelativeaccuracytesting,performthemeasurementsasdescribedabove,anddetermineifthemeanpollutantconcentrationismorethan10%differentfromanysinglepoint.Ifso,thecrosssectionisconsideredtobestratified,andthetestermaynotusethealternativetraversepointlocationsasdescribedin40CFRPart60,AppendixB,Performance .&*4 Specification2,section3.2(...0.4,1.2,and2.0metersfromthestackorductwall.)butmustusethethreetraversepointsat16.7,50.0,and83.3percentoftheentiremeasurementline. REFERENCES   P 1.0  GaseousContinuousEmissionMonitoringSystemsPerformance z  SpecificationGuidelinesforSO2,CO2,O2,andTRS,EPA450/382026, N  October1982,page9. %% 2.0  APTICourse474,ContinuousEmissionsMonitoringSystems,Student T  Manual,450/291006a,May1992,RevisedDraft,pages5254. %% 3.0  TransportableContinuousEmissionMonitoringSystemOperational F  Protocol:InstrumentalMonitoringofSO2,NO2,CO2,O2,Effluent   Concentrations,July1982,page2. %%