1、Designation: F 2638 07Standard Test Method forUsing Aerosol Filtration for Measuring the Performance ofPorous Packaging Materials as a Surrogate MicrobialBarrier1This standard is issued under the fixed designation F 2638; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method measures the aerosol filtration perfor-mance of p
3、orous 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 materials usedto package terminally sterilized medical devices.1.3 The intent o
4、f 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 testmethod. The maximum penetration point of a particular mate-rial could occur
5、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 byISO 56363.1.4 The values stated in SI units are to be regarded as thestand
6、ard. 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 establish appro-priate safety and health practices and determine the applica-
7、bility of regulatory limitations prior to use.2. Referenced Documents2.1 ISO Standard:2ISO 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 ef
8、fective particle counting in thefiltrate aerosol.3.1.2 filtrate aerosolparticles that remain aerosolized af-ter passage 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 differe
9、ntials or air flow rates.3.2 Abbreviations 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 particl
10、e count of the filtrate aerosol prior tocorrection for dilution.R % Percentage of particles from 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 P
11、ressure differential across a test specimen.F L/m/cm2Air flow rate through the test specimen.F1L/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 t
12、he testequipment described in this test method emit an aerosol ofpolystyrene particles and salt 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
13、ina sample holder in such a way as to create a filter between thechallenge and filtrate aerosols. 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
14、 monitorthe particle concentrations in the challenge and filtrate aero-sols. Particle concentrations will be measured over a range of1This test method is under the jurisdiction of ASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.15 onChemical/ Safe
15、ty Properties.Current edition approved Aug. 1, 2007. Published September 2007.2Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
16、2959, United States.flow 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 deviation of less than
17、 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 each test flow rat
18、e.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 concentration of the
19、 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 concentration for a given
20、 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 period of not less
21、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 measurements at flo
22、w 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 Air Dispersion Limi
23、ted (Manchester,UK) and funded by the Barrier Test Consortium Limited. Theresults of this research have been published in a peer-reviewedjournal.3This research demonstrated that testing the barrierperformance of porous packaging materials using microorgan-isms correlates with measuring the filtratio
24、n 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 efficiency curve is3“Definit
25、ion 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.NOTEThe point of maximum penetration is indicated by the upward pointing triangle.FIG. 1 A Typical Curve Showi
26、ng Penetration as a Function of Flow RateF2638072determined (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.
27、6.4 The particle filtration method is a 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 ofTa
28、llentire and Sinclair3and uses physical 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
29、of all com-ponents will be available in 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 tw
30、o assemblies,which form identical upper 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 Crit
31、ical Orifice, 40 m orifice.7.2 Aerosol GeneratorAconventional 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 usedNOTEDimensions of the ca
32、vity in mm. The configuration of the top and bottom cavity is identical.FIG. 2 Dimensions of the Sample CavityF2638073with a dual particle counter system as they exhibit sudden, unpredictablechanges in aerosol concentration.7.3 Particle CounterThe particle counter required for thistest method must b
33、e 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 specimen atmaximum penetration. I
34、f 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 s. When using the Lasairparti
35、cle 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(0.002 in.) WC to monitor the
36、 pressure difference across thesample.FIG. 3 Equipment Configuration for a Single Particle CounterMethod AF26380747.6 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
37、Nitrile Rubber SAE Standard AS 568ASize345 O-ringsProvide 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
38、have all been foundsatisfactory).8.4 Distilled 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
39、Solution:FIG. 4 Equipment Configuration for Dual Particle CountersMethod BF26380759.2.1.1 Prepare a 0.02 % v/v solution 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 meas
40、uring thechallenge aerosol. Ideally there should be no particles over 0.7m in diameter detected. The aim is no more than 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,
41、 each row being a 6-scounting interval.9.2.2 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 source (such as Duke Scientific5100A) some
42、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 the particles.9.2.2.2 Check for particle co
43、ncentration 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 interval in a Lasair1003).9.2.2.3 Check for
44、 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,there will be significant errors due to coinci
45、dence (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 so that it completely coversthe O-ring in th
46、e 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 counter. Fig. 5 shows an example of thepar
47、ticle 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. There-fore, an estimate must be made of the challenge aerosolconcentration at the time of the filtrate measu
48、rement.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 ensur
49、e water is cleanas described in 9.2.1.11.1.4 Prepare appropriate concentration (200 to 8000particles/mL) of PSL suspension and confirm that the particlecounts are within 3 % as described in 9.2.2.3.11.1.5 Open sample holder and place sample in the sampleholder.11.1.6 Select High Flow Range.11.1.7 Start aerosol flow, set Particle Counter to countChallenge.11.1.8 Close the venturi needle valve and increase inlet airpressure to 3 bar, open the needle valve until pressure differ-ential across the sample is 2 cm WC. Allow system to stabilizefor at le
