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LaboratoryVentilationFlowRatesatCornell:RethinkingtheTraditionRalphStuart,CIHChemicalHygieneOfficerDept.ofEnvironmentalHealthandSafetyrstuart@cornell.eduNovember,2012Agenda1.LaboratoryVentilationaspartoftheLaboratorySafetySystem2.Cornellʼslabairreductionpractices3.Movingforward:theLaboratoryVentilationManagementPlanWhatisaLab?•Laboratoriesareworkplaceswherepeopledounusualthingswithhazardousmaterials•Genericstrategiesareusedtoprotecttheworkersandtheirscience:1.Hazardreplacementordownsizing2.Facilitydesignandoperation3.Workertrainingandoversight4.Personalprotectiveequipmentandemergencyresponseplans•ThisflexibleapproachtosafetymaximizesthekindsofworkthefacilitycanhostToday’sLabVentilationSystem•Fumehoods•GeneralLaboratoryVentilation•ChemicalStorageCabinetsGeneralLabVentilationSpecificationsforSafetyPurposes•AirQuality:use100%outsideairtoavoidrecirculatingcontaminantsoriginatinginthelab•AirQuantity:•Thelate20thcenturyapproach:
10-12ACH24/7inalllabs•The21stcenturyapproach:
ACHdependsonwhatʼshappeningintheroomandhoweffectivetheventilationis•Ventilationrequirementscanbedrivenby:•Controlofchemicalsandotherhazards•Localexhaustrequirements•Temperature(solarandplugload)EnergyConservationInitiativeProgram§Campuswidemulti-phaseplan(2002–2017)§Goalistoreduceyear-2000energyuse20%§Programincludesenergyconservationfocusedmaintenance,studies,andprojects–datadriven§ProgramsupportedbyNYSERDArebatesKeyenergyconservationopportunitiesinlaboratories§Re-commissioningcontrolsystemstoreduceoutsideairuse§Useoccupancysensorstocontroloccupied/unoccupiedairflowsandlighting§Relaxtemperaturesduringunoccupiedtimetoreducereheatrequirements§RetrofitenvironmentalchambersReducingGeneralAirFlow
usingCFDmodelling§Afull3DCFDmodelwasbuiltinFluentsoftwarefor3buildings(one1950ʼs,one1980ʼs,one1990ʼsrenovation)§Resultsshowedthatinthe1980ʼsbuilding(Bioteach),8/4wasnotclearingspillseffectively§ModelresultswereverifiedbyqualitativesmoketestsBiotechnologyexistingductworkExisting8”roundperforatedsupplyExistinggeneralFivefootVAVfumehoodexhaustgrilleBiotechnologynewductworkdesignBiotechnologybuildingresults•CFDmodelingfoundthat,afterredesign,spillswereclearedwellenoughat6/3toavoidOSHAPELs•90fumehoodzones=~$180,000renovationcost•Savings~$1200/labeachyear,lessthana2yearsimplepayback!•Buildingoperatingcostswentfrom$1.2million/yearto$900,000/yearLessonsLearned(2008)•Cornellʼshistoricbuildingstockmeansthatthegeneralventilationdecisionisnotassimpleas“justdoit”•Ventilationeffectivenessinalabmustbeevaluatedonaroombasis•CFDisacosteffectivetooltoevaluatecurrentandproposeddesignsTheNextPhase:ControlBandingLabs•Westartwithastandardminimumof8ACHwhenthelabisunoccupiedand4ACHwhenunoccupiedtocontrolchemicalconcentrations(temperatureandexhaustcanoverridetheseminimums)•Wereviewthecurrentchemistrytoidentifylabswhere6ACHand3ACHcanbeexpectedtocontrolchemicalhazards.•Therearespecialcasesoutsidethesegenericcategories(e.g.animalareas,BSLroomsandmachineshops(oncethroughairataround2ACH)).•Overthelast1.5years,wehavevisitedabout600laboratoriesatCornellandthemajoritycanrunat6/3,iffumeshoodsareusedandventilationiseffectiveEvaluatingthe
VentilationEffectivenessCaveat•WeusefireextinguisherstoreleaseCO2andmeasurechemicalconcentrationdecaypatternswithinalaboratoryAnotherVentilatio...