Author:DennisMcCulloughCleanDesignPrinciples‘Do/Don’ts’forSurfaceFinishesMicro/CleanDesignDo-Don’tsareprimarilyreferencetrainingmaterials;forP&Gprojectexecution,alwaysrefertotheCleanDesignStandards.Micro/CleanDesignPrinciplesCleanDesignSpecsforSurfaceFinishesDesign:InertMaterials316LSSAvoidanceofthermoplasticsFRPselectionuseSurfacefinishRa<0.8microns(32micro-inches)SmoothsurfacesAvoidanceofbio-filmsPreventproduct/materialaccumulationWeldspolishedandgoodqualityProtectedagainstcontaminationfromoutsideenvironmentMINIMALRISK(=standardfornewequipment)MODERATERISKHIGHRISKSS316LSS316LowergradeSSFRPThermoplasticsMinimumRa0.8μm(32μinch)Ra0.8-1.0μm(32-42μinch)MuchhigherRaInternalweldsgroundsmoothandpolishedInternalweldsgroundsmoothInternalweldsnottreatedCheckyourMOCcompatibilitywithyourproduct&sanitizingagentwithCETL!Micro/CleanDesignPrinciplesSurfaceFinishes:MaterialsofConstructionMoredetails:SeeP&GCleanDesignStandardsoncGMPsiteMicro/CleanDesignPrinciplesInertMaterialsInerttoproduct,processconditionscleaning/sanitizingagentsNonreactive,additiveorabsorptiveStructuralconsiderationsProductdeterminesmaterialofchoiceStainlesssteel–316LSinglepolymerplastic-PE,PP,PTFESeals&gaskets-EPDM,PTFE,Viton,SiliconeAggressiveproducts/materials-highergradealloys;e.g.,TitaniumCostaconsiderationbutnottheconsiderationMicro/CleanDesignPrinciplesInertMaterials“Do”“Don’t”316L;SurfacefinishRa<0.8microns(32micro-inches)Poorsurfacefinishquality;leadstowatercollectionafterCIP/SIPGoodsurfacefinishqualityRA<0.8microns(32micro-inches);leadstohigherqualityCIP/SIPMicro/CleanDesignPrinciples“Do”“Don’t”316L;SurfacefinishRa<0.8microns(32micro-inches)InertMaterialsMicro/CleanDesignPrinciplesInertMaterials“Don’t”Avoidanceofthermoplastics;irregularsurfacesElastomeruseforPipingconnectiontoFillerUnloadinghoseribbed;OpentotheenvironmentFillercomponentthermoplasticsusceptibletocontaminatesMicro/CleanDesignPrinciples“Do”“Don’t”AvoidFRPTanksInertMaterialsNote:Unfilteredvent(“Don’t”)InsuspensionOnasurfaceBiofilms>90%MOsliveinbiofilmsoronsurfacesAdvantagescontinuoussupplyofnutrientsoxygenprotectionremovalofmetabolicwasteMicro/CleanDesignPrinciplesBiofilms=BacteriaManyspecies–oftenslimeformers,e.g.PseudomonasfluorescensColonisationprocess 1-initialattachment 2-irreversibleattachment 3-maturationI 4-maturationII 5-dispersion[Davis,2007,PLoSBiology5(11)e307Wikepedia]Micro/CleanDesignPrinciplesMicro/CleanDesignPrinciplesBiofilmsCollectionofmicrobesadheredtoasurfaceMicrobialcommunityGelorslimeproductionVariablethicknessResistantPhysiologicallydifferentProductAccumulationwhichhasledtotheFormationofaBiofilm“Don’t”12Biofilminsidewaterstoragevessel*BiofilmformationswithinmechanicallyfinishedstainlesssteelMicro/CleanDesignPrinciplesBiofilms“Don’t”O(jiān)rganiccontamination,andinseverecases“biofilm”,occurswhenbacteriaformprotectiveclustersonthemetalsurface.Surfaceroughnessandporositycausedbycorrosionpromotesbio-colonization.Electro-polishingandpassivationcancorrectdamaged316LSSsurfaces.*PicturecourtesyofAstroPakMicro/CleanDesignPrinciples*PicturecourtesyofAstroPakBiofilms“Do”“Don’t”Goalistominimizebio-filmformationMicro/CleanDesignPrinciplesSmoothSurfacesFacilitatescleaning;aidsremovalofbiofilmsduringcleaningMaintainedthroughjoints,welds,pumps,valves,mixersandancillaryequipmentSpecifiedinoriginaldesign--Minimumspecification0.8μmRaProductaccumulation：InhibitscleaninginplaceIdealMicrobiologicalhabitatComplicatesCleaning&SanitizationPreventionispartofthebasicdesignResidues,interruptedflowofmaterialStratificationofmaterialsDeadlegsincirculatingsystemsMicro/CleanDesignPrinciplesSmoothSurfaces“Do”“Don’t”RoughnessAverageNormalStainlessSteelPolishedStainlessSteelMicro/CleanDesignPrinciples“Do”“Don’t”SmoothSurfacesEssentialtominimizebio-filmformationMicro/CleanDesignPrinciplesSmoothSurfacesEssentialtominimizebio-filmformationIssue:PassivationQualityNewconstruction;3monthsservice*WeldmentareaofelectropolishedtubingIronoxidecrystalsattachedonweldarea“Don’t”*PicturecourtesyofAstroPakMicro/CleanDesignPrinciplesSmoothSurfacesEssentialtominimizebio-filmformationIssue:PassivationFrequency6yearsservice*IroncrystalsandoxideparticulatesonsurfacePittingrevealedafterde-rougingandpassivation“Don’t”*PicturecourtesyofAstroPakMicro/CleanDesignPrinciplesSmoothSurfacesEssentialtominimizebio-filmformationIssue:PassivationFrequency4yearsservice/ozonatedROservice*MechanicallypolishedsurfacewithClassIIrougeIronparticulatesonsurface“Don’t”*PicturecourtesyofAstroPakMicro/CleanDesignPrinciplesSmoothSurfacesEssentialtominimizebio-filmformationIssue:PassivationFrequency10yearsPureSteamservice*6yearssincelastpassivationMechanicallypolishedsurfacewithClassIIIrougeMagnetiteandhematiteoxidecrystals/particles“Don’t”*PicturecourtesyofAstroPakMicro/CleanDesignPrinciples“Do”“Don’t”TankDesign:MOCcorrect;surfacefinishRa<0.8microns(32micro-inches)/weldspolishedandgoodqualitySurfaceFinishesTankRougeMicro/CleanDesignPrinciplesSurfaceFinishes“Do”“Don’t”TankDesign:MOCcorrect;surfacefinishRa<0.8microns(32micro-inches)/weldspolishedandgoodqualityAvoiduseofflattoptanksMicro/CleanDesignPrinciplesSurfaceFinishes“Do”&Don’tExampleisaSanitaryBevelSeatAcmeThreadedConnection(Externalthreaddesign)Forlow-pressureapplicationsthereisnogasketrequiredwiththisfitting.Thethreadedsectionscanbequicklydisassembledwhererequiredforcleaning.Forhigherpressureapplications,agasketisrequired.Afactoristoconsiderwhatiscalled“coldflow”or“gasketmemory”.Manyofthematerialsusedforthesegasketswillnotreturntotheiroriginalshapeoncecompressedbetweentwoferrules/clamp(especiallyiftheclamphasbeenovertorqued).Consequently,whenthegasketisre-installeditwillnotcompressasitdidbeforeresultinginverysmallgapsthatwillimpact“surfaceflow”thatwilleventuallyleak.Gasketmaterialwithcoldflowproperties(likeunfilledTeflon?)maybeusedifreplacedwithanewgasketeachtimetheclampisremovedandreplaced.Boththemaleandfemalesectionsshouldberelativelyeasytocleaninplace.

Ifdisassemblyrequiredtoclean,the

femalesection(left)mayrequiredfocusedcleaningduetotheconnectedexternalthreads..Also,thegasketmaterialshoulde