1、Designation: F2638 121Standard Test Method forUsing Aerosol Filtration for Measuring the Performance ofPorous Packaging Materials as a Surrogate MicrobialBarrier1This standard is issued under the fixed designation F2638; the number immediately following the designation indicates the year oforiginal
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThe research report designation was added editorially in November 2016.1. S
3、cope1.1 This test method measures the aerosol filtration perfor-mance of porous packaging materials by creating a definedaerosol of 1.0 m particles and assessing the filtration effi-ciency of the material using either single or dual particlecounters.1.2 This test method is applicable to porous mater
4、ials usedto package terminally sterilized medical devices.1.3 The intent of this test method is to determine the flowrate through a material at which maximum penetration occurs.The porous nature of some materials used in sterile packagingapplications might preclude evaluation by means of this testme
5、thod. The maximum penetration point of a particular mate-rial could occur at a flow rate that exceeds the flow capacity ofthe test apparatus. As such, this test method may not be usefulfor evaluating the maximum penetration point of materials witha Bendtsen flow rate above 4000 mL/min as measured by
6、ISO 56363.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to est
7、ablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermin
8、e the Precision of a Test Method2.2 ISO Standard:3ISO 56363 Paper and BoardDetermination of Air Per-meance (Medium Range)Part 3: Bendtsen Method3. Terminology3.1 Definitions:3.1.1 challenge aerosola sufficient quantity of aerosolized1.0 m particles that enable effective particle counting in thefiltr
9、ate aerosol.3.1.2 filtrate aerosolparticles that remain aerosolized afterpassage through the test specimen.3.1.3 maximum penetrationthe highest percent concentra-tion of particles in the filtrate aerosol when a specimen is testedover a range of pressure differentials or air flow rates.3.2 Abbreviati
10、ons and Symbols:Symbol Unit DescriptionCSn Average particle count of the challenge aerosolwhen using a single particle counter (Method A).CFn Average particle count of the filtrate aerosol.CCn Average particle count of the challenge aerosol.CLRN Average particle count of the filtrate aerosol prior t
11、ocorrection for dilution.1This test method is under the jurisdiction of ASTM Committee F02 on PrimaryBarrier Packaging and is the direct responsibility of Subcommittee F02.15 onChemical/Safety Properties.Current edition approved May 1, 2012. Published June 2012. Originallyapproved in 2007. Last prev
12、ious edition approved in 2007 as F2638 07. DOI:10.1520/F2638-12E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM we
13、bsite.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Symbol Unit DescriptionR % Percentage of particles fr
14、om the challenge aerosolthat remain in the filtrate aerosol.RM% The calculated maximum of R.P1cm WC Pressure differential across a test specimen due tothe air flow required by the particle counter.P cm WC Pressure differential across a test specimen.F L/m/cm2Air flow rate through the test specimen.F
15、1L/m/cm2Air flow rate required by the particle counter whenmeasuring the filtrate aerosol.FML/m/cm2Air flow rate at which maximum penetration occurs.4. Safety4.1 The waste and the vacuum venturi vents for the testequipment described in this test method emit an aerosol ofpolystyrene particles and sal
16、t residues. These aerosols shouldbe exhausted from any enclosed environment or collected andfiltered to remove all particles.5. Summary of Test Method5.1 A porous packaging material test specimen is placed ina sample holder in such a way as to create a filter between thechallenge and filtrate aeroso
17、ls. On the challenge side of thesample holder, an aerosol of particles is presented to thesurface of the test specimen. An air flow is generated throughthe test specimen. A laser particle counter is used to monitorthe particle concentrations in the challenge and filtrate aero-sols. Particle concentr
18、ations will be measured over a range offlow rates in order to measure the percent penetration over therange of flow rates and determine the point of maximumpenetration.5.2 This test uses an aerosol of polystyrene latex particles(PSL) with a geometric mean particle diameter of 1.0 m anda standard dev
19、iation of less than 0.05 m.5.2.1 A single particle counter may be used to sequentiallymeasure the challenge and filtrate aerosols or two particlecounters may be used to measure them continuously. Whenusing a single particle counter the challenge and filtrateaerosols will be sequentially measured for
20、 each test flow rate.The filtrate aerosol concentration is reported as the averageconcentration of the filtrate aerosol over a time period of 45 to60 s, beginning no sooner than 1 min from the start of thefiltrate aerosol measurement. The challenge aerosol concentra-tion is reported as the average c
21、oncentration of the challengeaerosol over a time period of not less than 45 s, beginning nosooner than 1 min from the start of the challenge measurement.Challenge concentrations measured immediately before andafter each filtrate concentration measurement are averaged todetermine the challenge concen
22、tration for a given flow rate.5.2.2 When using two particle counters, the challenge andfiltrate aerosols are counted continuously by dedicated particlecounters. The challenge and filtrate aerosol concentrations arereported as the average concentration of the challenge orfiltrate aerosol over a time
23、period of not less than 45 s,beginning no sooner than 1 min after a change in flow rate.5.3 At the pressures used in this test, pressure differentialacross the sample and flow rate through the material aredirectly proportional. Pressure will be varied over a range thatwill ideally have at least two
24、measurements at flow rates thatare higher and lower than the flow rate that demonstrates themaximum penetration.5.4 The reported results are the maximum penetration andthe flow rate at which it occurs.6. Significance and Use6.1 This test method has been developed as a result ofresearch performed by
25、Air Dispersion Limited (Manchester,UK) and funded by the Barrier Test Consortium Limited. Theresults of this research have been published in a peer-reviewedjournal.4This research demonstrated that testing the barrierperformance of porous packaging materials using microorgan-isms correlates with meas
26、uring the filtration efficiency of thematerials.6.2 This test method does not require the use of microbio-logical method; in addition, the test method can be conductedin a rapid and timely manner.6.3 When measuring the filtration efficiency of porouspackaging materials a typical filtration efficienc
27、y curve isdetermined (see Fig. 1). Since the arc of these curves isdependent upon the characteristics of each individual material,the appropriate way to make comparison among materials isusing the parameter that measures maximum penetrationthrough the material.6.4 The particle filtration method is a
28、 quantitative procedurefor determining the microbial barrier properties of materialsusing a challenge of 1.0 m particles over range of pressuredifferentials from near zero to approximately 30 cm watercolumn (WC). This test method is based upon the research ofTallentire and Sinclair4and uses physical
29、 test methodology toallow for a rapid determination of microbial barrier perfor-mance.7. Apparatus7.1 Test FixtureThis consists of a base with associatedvalves, tubing, sample holder and clamps necessary to performthe test. Dimensioned drawings and arrangement of all com-ponents will be available in
30、 a future research report. Dimen-sions of the sample holder (Fig. 2) and schematics of the singleparticle counter (Fig. 3) and dual particle counter (Fig. 4) areshown. The significant components of the text fixture include:7.1.1 Sample HolderThis consists of two assemblies,which form identical upper
31、 and lower manifolds and samplecavities that deliver a uniform flow of the aerosol or sweep airto the periphery of the test specimen while extracting it fromthe center.7.1.2 Normal Flow Range Needle Valve, 500 m diametermaximum orifice.7.1.3 Low Flow Range Critical Orifice, 40 m orifice.7.2 Aerosol
32、GeneratorA conventional vertical style medi-cal nebulizer is the preferred aerosol generator for use in asingle counter system (Particle Measuring Systems PG100 orequivalent).NOTE 1Atomizer style nebulizers are not recommended unless usedwith a dual particle counter system as they exhibit sudden, un
33、predictable4“Definition of a Correlation Between Microbiological and Physical ParticulateBarrier Performances for Porous Medical Packaging Materials,” PDA J Pharm SciTechnol, Vol 56, No. 1, 2002, Jan-Feb, 11-9.F2638 1212changes in aerosol concentration.7.3 Particle CounterThe particle counter requir
34、ed for thistest method must be capable of distinguishing between theresidue from water droplets and the polystyrene latex (PSL)particles (Particle Measuring Systems Lasair series of countersor equivalent). The particle counter should have a flow demandthat approximates the flow through the test spec
35、imen atmaximum penetration. If the particle counter sorts particles bysize, it must be determined in which size ranges the PSLparticles reside.7.4 Data LoggingThe elapsed test time, the pressuredifferential, the total challenge particles, and/or the total filtrateparticles shall be recorded every 6
36、s. When using the Lasairparticle counters, the 1.0 m PSL particles are counted in boththe 0.7 to 1.0 m and the 1.0 to 2.0 m size ranges. Therefore,both counts shall be recorded and totaled.7.5 ManometerA precision manometer with a minimumrange of 0 to 5 cm (0 to 2 in.) WC and an accuracy of 0.005 cm
37、(0.002 in.) WC to monitor the pressure difference across thesample.7.6 Pressure RegulatorPrecision regulator capable of de-livering 1.0 standard litre per minute at pressures up to 3 bar.7.7 ULPA FilterRequired to remove ambient particles.7.8 Buna N or Nitrile Rubber SAE Standard AS 568ASize345 O-ri
38、ngsProvide a seal between the challenge andfiltrate sides of the test.8. Materials8.1 Particle free, dry compressed air.8.2 Tween 20 or sodium dodecylsulfate (SDS).8.3 Concentrate suspension of 1 m PSL particles (DukeScientific 3K1000, 5100A, and G0100 have all been foundsatisfactory).8.4 Distilled
39、water sufficiently free of dissolved material.8.5 Porous packaging material.9. Apparatus Preparation9.1 Apparatus should be assembled as seen in Fig. 3 (singleparticle counter) or Fig. 4 (dual particle counter).9.2 Material Preparation:9.2.1 Surfactant Solution:9.2.1.1 Prepare a 0.02 % v/v solution
40、of surfactant (Tween20, SDS, or equivalent) in distilled water daily.9.2.1.2 Aerosolize the surfactant solution and determine theparticle size distribution of this solution by measuring thechallenge aerosol. Ideally there should be no particles over 0.7m in diameter detected. The aim is no more than
41、 2 suchparticles detected within any 6-s period. Monitor surfactantsolution for 1 min.9.2.1.3 Table 1 is an example of the size distribution ofsurfactant solution suitable for use, each row being a 6-scounting interval.NOTE 1The point of maximum penetration is indicated by the upward pointing triang
42、le.FIG. 1 A Typical Curve Showing Penetration as a Function of Flow RateF2638 12139.2.2 Particle Suspension:9.2.2.1 Prepare a suspension of 1 m PSL particles in thesurfactant solution described above.NOTE 2This solution is to be made fresh daily. When making thesuspension from a highly concentrated
43、source (such as Duke Scientific5100A) some of the particles will have agglomerated into aggregatesconsisting of multiple particles. To ensure the aerosol consists of particleshaving only one PSL particle, place the bottle containing the solution in anultrasonic bath for 15 s. This will disassociate
44、the particles.9.2.2.2 Check for particle concentration by monitoringcounts in particle counter for 1 min without any sample insample holder. The resulting challenge aerosol particle concen-tration must be within the range of 200 to 8000 particles per cc(this is equal to 600 to 24 000 counts per 6-s
45、interval in a Lasair1003).9.2.2.3 Check for instrument bias by measuring the chal-lenge counts with the test specimen in place. Then remove thespecimen and measure filtrate results. Check that the countsdiffer by no more than 3 %.NOTE 3If concentrations higher than 8000 particles per cc are used,the
46、re will be significant errors due to coincidence (counting two particlesas a single particle) in the particle counter detector.10. Sample Preparation10.1 Cut a sample of porous barrier material no less than120 mm (the area of the sample exposed to the aerosol is 100mm in diameter) in any dimension s
47、o that it completely coversthe O-ring in the lower half of the sample holder. The samplemust cover the entire circumference of the seal O-ring. Criticaldimensions of the exposure chamber are shown in Fig. 2.11. Test Procedures11.1 Method A Single Particle CounterProcedure whenusing a single particle
48、 counter. Fig. 5 shows an example of theparticle count results of a typical single measurement withreadings every 6 s.11.1.1 When only a single particle counter is in use, it mustbe switched between the challenge and filtrate aerosol.NOTE 1Dimensions of the cavity in mm. The configuration of the top
49、 and bottom cavity is identical.FIG. 2 Dimensions of the Sample CavityF2638 1214Therefore, an estimate must be made of the challenge aerosolconcentration at the time of the filtrate measurement.11.1.2 Set up equipment for 1 particle counter mode, use 0.7to 1.0 m and 1.0 to 2.0 m bin data, record Lasair andmanometer data every 6 s. Record pressure drop across sampleduring each 6-s sample length while counting particles infiltrate stream.11.1.3 Test distilled water/surfactant to ensure water is cleanas described in 9.2.1.11.1.4 Prepare
