Testing Results of KN 95 Respirators.docx

Testing Results of KN 95 Respirators.docx

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TestingResultsofKN95Respirators

TestingResultsofKN95RespiratorsAccordingtoGB2626-2006

FinalReport

Submittedto:

TheOfficeofAttorneyGeneralofCanada（AGC）

Submittedby:

ShawnChen

VirginiaCommonwealthUniversity

February14,2022

1ExecutiveSummary

ThisreportprovidestheparticleremovalefficienciesoftestedKN95respiratorsfromall23lotsreceivedfromtheOfficeofAttorneyGeneralofCanada,including202004BF（Bag22A）,20200412（Bag2）,202004NW（Bag22B）,20200422（Bag14）,20200408（Bag1）,20042015A03（Bag5）,20042015A07（Bag7）,20200420（Bag10）,20200420（Bag11）,20200423X（Bag17）,20200424（Bag18）,20200424X（Bag19）,20200429X（Bag20）,CY-20200421-1（Bag23）,T202004（Bag25）,20200420（Bag12）,20200422（Bag15）,20200423（Bag16）,20200430X（Bag21）,20042015A01（Bag3）,20042015A02（Bag4）,20042015A05（Bag6）and20200420（Bag9）.ThetestingprocedureswerevigorouslybasedontheStandardOperatingProcedure（SOP）pursuanttotheChinesestandardGB2626-2006（Respiratoryprotectiveequipment-Non-poweredair-purifyingparticlerespirator）.Amongstthe345randomlypickedandtestedKN95respirators（15respirators×23lots）,122ofthempassedthe95%efficiencyrequirement.Onlylot20200423Xoutof23havingall15respiratorspassed95%efficiencyrequirement.

2Objective

ThistechnicalreportaimstoprovidethefiltrationefficiencymeasurementresultsofKN95masksprovidedbytheAttorneyGeneralofCanada,AGC.

3Procedures

ToobtainreliableandrepresentativeresultsfortheparticleremovalefficiencyoftestedKN95respirators,theSOPwasfollowed.

3.1Visualappearanceinspection

Allthetestedrespiratorswerecheckedintermsoftheirappearance.AppendixA（Visualinspectionform）attachedtothisdocumentsummarizestheinspectionresultsofallthetestedsamples.

3.2Respiratorsamplelabelingandstorage

Therespiratorslabelledwith1-5arereferredtopretreatedsamplesforeachLot,andtherespiratorslabelledwith6-15arenon-pretreatedsamples.

∙LabellinginformationofallrespiratorsprovidedbyAGCwasfollowedandappliedthroughwholetestingprocesses.

∙Everyrespiratorwasstoredinanindividualzipperbagwithairtightandhaditslabelwrittenoutsidethebagwithapermanentmarker.

∙Alllabelledrespiratorswerestoredinanenvironment-controlledcabinetwithatemperatureof20±2℃andrelativehumidity（RH）of40±10%beforethepretreatment（refertoSOP3.1-3.6）andefficiencytest（refertoSOP4.1-4.3）.

3.3Pretreatmentbeforefiltrationefficiencytesting

Respirators1-5fromeachLotwerepretreatedwiththeproceduresaccordingtoSOP3.1-3.5.AppendixB（Pretreatmentform）oftheSOPwasusedtorecordthetimeandconditionforallthepretreatedsamples.

∙Briefly,5randomlyselectedsampleswerefirstlypretreatedwithtemperatureandRHat38±2.5℃and85±5%,respectively,for24±1hours.Thenthetreatedsampleswererecoveredtoroomtemperaturefor4hoursbeforeconductingthesecondpretreatment.

∙Thesecondpretreatmentwastoplacethe5samplesunderRH<30%and70±3℃intheVWRforcedairovenforanother24±1hours.Thetreatedsampleswererecoveredtoroomtemperatureagainfor4hoursbeforeconductingthethirdpretreatment.

∙Thethirdpretreatmentwastoconditionthe5samplesunder-30±3℃intheSummitVT65freezerforanother24±1hours.Thetreatedsampleswererecoveredtoroomtemperatureagainfor4hoursbeforeconductingtheefficiencytests.

3.4Filtrationefficiencytesting

TheefficiencytestingwasconductedaccordingtotheSOP4.1–4.4.Beforethetest,theproceduresasfollowswerecarriedout:

∙Thescanningmobilityparticlesizer（SMPS,model3936,TSIInc.,Shoreview,MN）formonitoringthesizedistributionofchallengingparticlesandtheDusttrak（model8530,TSIInc.,Shoreview,MN）fordeterminingthefiltrationefficiencywerefirstcalibratedaccordingtothemanualsfromTSI.

∙1~3wt.%NaClsolutionwerepreparedfortheatomizertogenerateNaClparticleswithacountmediandiameter（CMD）of0.075±0.020μmandageometricstandarddeviation（σg）lessthan1.86.TheCMDandσgwasmonitoredbytheSMPSeverydaybeforetesting.

∙TheleaktestswereperformedbyusingsecondmethodprovidedbySOP4.4.5,i.e.,theCPCmeasurement,beforeeachsample’sefficiencytest.

∙Beforedeterminingthefiltrationefficiencyoftherespirator,thefiltrationefficiencytestwithoutplacingtherespirator（i.e.,ηwithout,namedlossefficiency）wasalsoconductedtoensuretherewasnegligibleparticletransportlossandleakinthefilterholder.

4ResultsandDiscussions

4.1Instrumentationcalibration

4.1.1SMPScalibration

TheSMPSwascalibratedbyutilizingstandardsize3070A（70±3nm）nanospheresfromFisherScientifictoconfirmtheSMPSbeingabletomeasureaccuratesizedistributionofthechallengingparticles.ArepresentativecalibrationresultsareshowninFig.1.TheCMDandσgofthedistributionis71.8nmand1.09,respectively,indicatingthesizingaccuracyoftheSMPSisreliable.

Figure1.Sizedistributionof70nmnanospheresmeasuredbytheSMPS.

4.1.2Dusttrakcalibration

TheDusttrakcalibrationhereinvolveszerocalibration,flowcalibrationandphotometriccalibrationfactor（PCF）calibration.ZerocalibrationwasperformedbyplacingaHEPAfilterattheinletwhentheinstrumentwasfirstused.Flowcalibrationwasconductedusingaprimarybubbleflowmetertoconfirmtheflowrateofthepump（3L/min）.Photometriccalibrationfactor（PCF）calibrationwasdeterminedwithNaClparticleswithaCMDof0.075±0.020μmandaσglessthan1.86.Fig.2showsthesizedistributionoftheaerosolizedNaClparticlesusedtochallengetheafterfilterinDusttrak.TheflowcalibrationresultsshowedthattheflowrateoftheDusttrakwas3.0±0.03L/min.Thephotometriccalibrationfactorwasfoundtobe0.15.

Figure2.SizedistributionofNaClparticlesusedtocalibratetheDusttrak.

4.2Sizedistributionoftheaerosolforchallengingtherespirators

AccordingtoSOP4.3.1,thesizedistributionoftheaerosolforchallengingtherespiratorsshouldbemonitoredeverydaybeforetheefficiencytesttomakesurethegeneratedNaClparticlesarewithaCMDof0.075±0.020μmandaσglessthan1.86.Herein,arepresentativesizedistributionforthechallengingparticlesisshowninFig.3forreference.

Figure3.SizedistributionofNaClparticlesusedtochallengetheKN95respirators.

4.3Leaktestresults

AsdescribedinSection3.4inthisreport,theleaktestswereconductedbyusingCPCtoconfirmnoleakoccurringwhenperformingtheefficiencytest.ArepresentativeresultofleaktestisshowninFig.4forreference.Asseen,thereisalmostnoparticledetectedforbothupstreamanddownstreammeasurement,whichdemonstratesthatthereisanegligibleleakbeforeconductingthefollowingefficiencytests.Theexistingparticleswithverylowconcentrationmaybefromtheductwallofthesetupbuttheywillnotaffecttheefficiencymeasurementastheconcentrationofchallengeparticleisintheorderof1x106.

Figure4.UpstreamanddownstreamnumberconcentrationofparticlesmeasuredbytheCPC.

4.4Lossefficiencytestresults

ThelossefficiencytestresultswereobtainedbyfollowingtheSOP4.5.Allthelossefficiencieswerecontrolledaslowaspossible,suchaswith<1%.Fig.5showsarepresentativelossefficiency（ηwithout）resultforthereference.Thelossefficiencyshownherewas0.96%.Thissmallamountofdifferenceofparticleconcentrationintheupstreamanddownstreamofthesamplingprobe（lossefficiency）shouldbeduethetransportlossofsmallparticleslessthan20nm.Tobenoted,thereallossforthemajorchallengeparticles,i.e.,75nm,shouldbemuchlowerandnegligible.

Figure5.UpstreamanddownstreamnumberconcentrationofparticlesmeasuredbytheCPC.

4.5Filtrationefficiencytestresults

TheefficiencytestresultswereobtainedbyfollowingtheSOP4.5.Table1summarizesthepassrateoftestedrespiratorsfromdifferentlots（total23lots）.Itisobservedtherewasnoclearinfluenceofpretreatmentontheefficiencytestresult.Thedetailedefficiency,pressuredrop,andotherrelateddataoftestedrespiratorsaresummarizedinAppendixC1~C23:

Lot202004BF（Bag22A）inC1;Lot20200412（Bag2）inC2;Lot202004NW（Bag22B）inC3;Lot20200422（Bag14）inC4;Lot20200408（Bag1）inC5;Lot20042015A03（Bag5）inC6;Lot20042015A07（Bag7）inC7;Lot20200420（Bag10）inC8;Lot20200420（Bag11）inC9;Lot20200423X（Bag17）inC10;Lot20200424（Bag18）inC11;Lot20200424X（Bag19）inC12;Lot20200429X（Bag20）inC13;LotCY-20200421-1（Bag23）inC14;LotT202004（Bag25）inC15;Lot20200420（Bag12）inC16,Lot20200422（Bag15）inC17,Lot20200423（Bag16）inC18,Lot20200430X（Bag21）inC19,Lot20042015A01（Bag3）inC20,Lot20042015A02（Bag4）inC21,Lot20042015A05（Bag6）inC22andLot20200420（Bag9）inC23.

Table1.Summaryofthepassratioofrespiratorsfromdifferentlots.

BagNo.

Lot

Passratio

Datain

22A

202004BF

3/15

AppendixA1

2

20200412

3/15

AppendixA2

22B

202004NW

3/15

AppendixA3

14

20200422

6/15

AppendixA4

1

20200408

6/15

AppendixA5

5

20042015A03

0/15

AppendixA6

7

20042015A07

0/15

AppendixA7

10

20200420

11/15

AppendixA8

11

20200420

0/15

AppendixA9

17

20200423X

15/15

AppendixA10

18

20200424

9/15

AppendixA11

19

20200424X

14/15

AppendixA12

20

20200429X

8/15

AppendixA13

23

CY-20200421-1

0/15

AppendixA14

25

T202004

9/15

AppendixA15

12

20200420

10/15

AppendixA16

15

20200422

9/15

AppendixA17

16

20200423

8/15

AppendixA18

21

20200430X

7/15

AppendixA19

3

20042015A01