2018-03_Presentation-Lab_Vent-Chem-Hoods.pdfVIP专享VIP免费原创优质

LaboratoryVentilationSafetyJ.ScottWardLabconcoSeniorTerritoryManagerLabconcoCorporationIn1925,LaboratoryConstructionCompanywasborn.ThefirstproductwasaKjeldahlNitrogenDeterminationApparatus.Wemayhaveshortenedourname,butwe’veexpandedourhorizons.Weoffer16differentproductlinestouniversities,researchcenters,hospitals,generallaboratoriesandgovernmentalagenciesaroundtheworld.Labconcohasbeenbuildingfumehoodsandotherventilationproductsforover80years.FirstLabconcoHood1936Fiberglass281960FiberglassWalk‐In1970sAnti‐VortexContainment2002VariableAirVolume1980CFMMinimization2012OurVentilationHistory8811ProspectKansasCity,MOFortScott,KansasLabconcoCorporation■Alchemistsin1800s■ThomasEdisonLaboratories1900•Fireplaceandchimney•Shelvesoutsidethewindow■UniversityofLeeds,England,1923•FumeCupboard■Commerciallyavailableinthe1930sUniversityofLeeds,England‐1923ThomasEdison1930shoodTheHistoryofFumeHoodsActualPhotoofaFumeCupboardinEdisonLaboratoriesAventilatedenclosurewhereharmfulortoxicfumesorvaporscanbesafelyhandledwhileprotectingthelaboratorytechnician.DefinitionofaFumeHoodTheprimaryfunctionofafumehoodistocapture,containandremoveairbornecontaminants.PurposeofaFumeHoodDefinition:Airflowintoahoodisachievedbyanexhaustblowerwhich“pulls”airfromthelaboratoryroomintoandthroughthehoodandexhaustsystem.This“pull”attheopeningofthehoodismeasuredasfacevelocity.RoomAirFaceVelocityExhaustAirAirvolumepassingthroughafumehoodisgenerallyequaltotheareaofthesashopeningmultipliedbytheaveragevelocitydesired.Forexample,if100feetperminute(fpm)isrequiredandthehoodhasasashopeningof7.5squarefeet,thenthehood’sairvolumeis750(7.5x100)cubicfeetperminute(CFM).AirVolumeAirFoilAerodynamicsashopeningdirectsairflowintohoodandacrossworksurfacewithminimumturbulencehelpingtoensurefumecontainment.DesignComponentsTheSASHcontrolstheareaofthefumehoodwhichisopen.Itprotectstheoperatorandcontrolshoodfacevelocities.Glassoptionsincludetemperedorlaminated.DesignComponentsSashVertical‐risingsashHorizontal‐slidingsashesCombination(verticalandhorizontalsashes)SafetySash:PhysicalBarrierTheBAFFLEcontrolsthepatternoftheairmovingintoandthroughthefumehoodBafflesareeitherfixed(leftphoto),oradjustable(rightphoto).FixedBaffleAdjustableBaffleDesignComponentsLinermaterialshouldbedeterminedbyapplicationandtypesandconcentrationofchemicalsbeinghandledwithinthehoodandexhaustsystem.LinerMaterialsEpoxy‐coatedsteelFiberglassreinforcedpolyester(FRP)Glassreinforcedcement(GRC)Stainlesssteel(Type316or304)PolypropylenePolyvinylchloride(PVC)Solidcompositepanel(polyresin)RestrictedBy‐PassWithSashOpenWithSashClosedReducedsashopeningCombinationSashReducedAirVolume(1950-1960s)VariableAirVolumehoodsmaintainthepre‐selectedfacevelocityproportionaltothesashopeningwhilemonitoringhoodconditionsforsafety.VariableAirVolumeFumeHoodDamperRestrictedBy‐PassOpeningDamperVariableAirVolume(1980s)WithSashOpenWithSashClosedFumehoodwithVAVcontrolsysteminstalledVariableAirVolumeValves(ordampers)locatedaroundroomsensedemandforincreasedsupplyairbasedonexhaustlevelsatfumehood.VariableAirVolumeBuildingLayout■SanDiegoGasandElectric,USDepartmentofEnergy■Push‐PullDesign■70%ReductioninCFM■DramaticContainmentIncreasedsafetyLBNLBerkeleyHood(Late1990s)■Operationatlowvelocities■Enhancedcontainment■UsedinconstantvolumeorvariableairvolumesystemsHighPerformance(...