1、Designation: F2638 121F2638 18Standard 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 ofo
2、riginal 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.1 NOTEThe research report designation was added editorially in November
3、2016.1. Scope1.1 This test method measures the aerosol filtration performance of porous packaging materials by creating a defined aerosolof 1.0 m particles and assessing the filtration efficiency of the material using either single or dual particle counters.1.2 This test method is applicable to poro
4、us materials used to package terminally sterilized medical devices.1.3 The intent of this test methodapparatus is to determine the flow rate through a material at which maximum penetrationoccurs. The porous nature of some materials used in sterile packaging applications might preclude evaluation by
5、means of this testmethod. The maximum penetration point of a particular material could occur at a flow rate that exceeds the flow capacity of thetest apparatus. As such, this test method may not be useful for evaluating the maximum penetration point of materials with aBendtsen flow rate above 4000 m
6、L/min as measured by ISO 56363.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user
7、 of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablish
8、ed in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E171/E171M Practice for Conditioning and Testing Flexible Barrier P
9、ackagingE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Standard:3ISO 56363 Paper and BoardDetermination of Air Permeance (Medium Range)Part 3: Bendtsen Method3. Termino
10、logy3.1 Definitions:3.1.1 challenge aerosola sufficient quantity of aerosolized 1.0 m particles that enable effective particle counting in the filtrateaerosol.3.1.2 filtrate aerosolparticles that remain aerosolized after passage through the test specimen.1 This test method is under the jurisdiction
11、of ASTM Committee F02 on Primary Barrier Packaging and is the direct responsibility of Subcommittee F02.15 onChemical/Safety Properties.Current edition approved May 1, 2012Sept. 1, 2018. Published June 2012September 2018. Originally approved in 2007. Last previous edition approved in 20072012 asF263
12、8 07.F2638 121. DOI: 10.1520/F2638-12E01.10.1520/F2638-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 A
13、vailable from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becau
14、seit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Ba
15、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3 maximum penetrationthe highest percent concentration of particles in the filtrate aerosol when a specimen is tested overa range of pressure differentials or air flow rates.3.2 Abbreviations and Symbols:Symbol Unit De
16、scriptionCS n Average particle count of the challenge aerosolwhen using a single particle counter (Method A).CF n Average particle count of the filtrate aerosol.CC n Average particle count of the challenge aerosol.CLR N Average particle count of the filtrate aerosol prior tocorrection for dilution.R
17、 % Percentage of particles from the challenge aerosolthat remain in the filtrate aerosol.RM % The calculated maximum of R.P1 cm 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/cm2 Air flow
18、rate through the test specimen.F1 L/m/cm2 Air flow rate required by the particle counter whenmeasuring the filtrate aerosol.FM L/m/cm2 Air flow rate at which maximum penetration occurs.4. Safety4.1 The waste and the vacuum venturi vents for the test equipment described in this test method emit an ae
19、rosol of polystyreneparticles and salt residues. These aerosols should be exhausted from any enclosed environment or collected and filtered to removeall particles.5. Summary of Test Method5.1 A porous packaging material test specimen is placed in a sample holder in such a way as to create a filter b
20、etween thechallenge and filtrate aerosols. On the challenge side of the sample holder, an aerosol of particles is presented to the surface ofthe test specimen. An air flow is generated through the test specimen. A laser particle counter is used to monitor the particleconcentrations in the challenge
21、and filtrate aerosols. Particle concentrations will be measured over a range of flow rates in orderto measure the percent penetration over the range of flow rates and determine the point of maximum penetration.5.2 This test uses an aerosol of polystyrene latex particles (PSL) with a geometric mean p
22、article diameter of 1.0 m and astandard deviation of less than 0.05 m.5.2.1 A single particle counter may be used to sequentially measure the challenge and filtrate aerosols or two particle countersmay be used to measure them continuously. When using a single particle counter the challenge and filtr
23、ate aerosols will besequentially measured for each test flow rate. The filtrate aerosol concentration is reported as the average concentration of thefiltrate aerosol over a time period of 45 to 60 s, beginning no sooner than 1 min from the start of the filtrate aerosol measurement.The challenge aero
24、sol concentration is reported as the average concentration of the challenge aerosol over a time period of not lessthan 45 s, beginning no sooner than 1 min from the start of the challenge measurement. Challenge concentrations measuredimmediately before and after each filtrate concentration measureme
25、nt are averaged to determine the challenge concentration fora given flow rate.5.2.2 When using two particle counters, the challenge and filtrate aerosols are counted continuously by dedicated particlecounters. The challenge and filtrate aerosol concentrations are reported as the average concentratio
26、n of the challenge or filtrateaerosol over a time 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 differential across the sample and flow rate through the material are directlyproportional. Pressure will be var
27、ied over a range that will ideally have at least two measurements at flow rates that are higher andlower than the flow rate that demonstrates the maximum penetration.5.4 The reported results are the maximum penetration and the flow rate at which it occurs.6. Significance and Use6.1 This test method
28、has been developed as a result of research performed by Air Dispersion Limited (Manchester, UK) andfunded by the Barrier Test Consortium Limited. The results of this research have been published in a peer-reviewed journal.4 Thisresearch demonstrated that testing the barrier performance of porous pac
29、kaging materials using microorganisms correlates withmeasuring the filtration efficiency of the materials.6.2 This test method does not require the use of microbiological method; in addition, the test method can be conducted in a rapidand timely manner.4 “Definition of a Correlation Between Microbio
30、logical and Physical Particulate Barrier Performances for Porous Medical Packaging Materials,” PDA J Pharm Sci Technol,Vol 56, No. 1, 2002, Jan-Feb, 11-9.F2638 1826.3 When measuring the filtration efficiency of porous packaging materials a typical filtration efficiency curve is determined (seeFig. 1
31、). Since the arc of these curves is dependent upon the characteristics of each individual material, the appropriate way to makecomparison among materials is using the parameter that measures maximum penetration through the material.6.4 The particle filtration method is a quantitative procedure for d
32、etermining the microbial barrier properties of materials usinga challenge of 1.0 m particles over range of pressure differentials from near zero to approximately 30 cm water column (WC).(WC) (2942 Pa).This test method is based upon the research ofTallentire and Sinclair4 and uses physical test metho
33、dology to allowfor a rapid determination of microbial barrier performance.7. Apparatus7.1 Test FixtureThis consists of a base with associated valves, tubing, sample holder and clamps necessary to perform the test.Dimensioned drawings and arrangement of all components will be available in a future re
34、search report. Dimensions of the sampleholder (Fig. 2) and schematics of the single particle counter (Fig. 3) and dual particle counter (Fig. 4) are shown. The significantcomponents of the text fixture include:7.1.1 Sample HolderThis consists of two assemblies, which form identical upper and lower m
35、anifolds and sample cavities thatdeliver a uniform flow of the aerosol or sweep air to the periphery of the test specimen while extracting it from the center. Toprovide consistent sample material placement in the sample holder, a meshed fixture is placed under the sample prior to the closingof the t
36、est fixture. Based on the fixture dimensions in Fig. 2; the mesh shall have a diameter of less than 100 mm and greater than90 mm to fit into the flow cavity. A mesh material of stainless steel T304; eight (8 by 8 per 2.54 cm) mesh T304 stainless steel0.7112 mm wire diameter; 2.46 mm opening size; 1.
37、4224 mm overall thickness; weave type PSW mill finish or equivalent isrecommended. The same fixture should be used, or the fixture noted, when comparing data.7.1.2 Normal Flow Range Needle Valve, 500 m diameter maximum orifice.7.1.3 Low Flow Range Critical Orifice, 40 m orifice.7.2 Aerosol Generator
38、A conventional vertical style medical nebulizer is the preferred aerosol generator for use in a singlecounter system (Particle Measuring Systems PG100 or equivalent).NOTE 1Atomizer style nebulizers are not recommended unless used with a dual particle counter system as they exhibit sudden, unpredicta
39、ble changesin aerosol concentration.NOTE 1The point of maximum penetration is indicated by the upward pointing triangle.FIG. 1 A Typical Curve Showing Penetration as a Function of Flow RateF2638 1837.3 Particle CounterThe particle counter required for this test method must be capable of distinguishi
40、ng between the residuefrom water droplets and the polystyrene latex (PSL) particles (Particle Measuring Systems Lasair series of counters or equivalent).The particle counter should have a flow demand that approximates the flow through the test specimen at maximum penetration.particles. If the partic
41、le counter sorts particles by size, it must be determined in which size ranges the PSL particles reside.7.4 Data LoggingThe elapsed test time, the pressure differential, the total challenge particles, and/or the total filtrate particlesshall be recorded every 6 s. When using the Lasair some particle
42、 counters, the 1.0 m PSL particles are counted in both the 0.7to 1.0 m and the 1.0 to 2.0 m size ranges. Therefore, both counts shall be recorded and totaled. The bin size difference is dueto particle variability.7.5 ManometerA precision manometer with a minimum range of 0 to 5 cm (0 to 2 in.) WC wa
43、ter column (WC) (0 to 490.3Pa) and an accuracy of 0.005 cm (0.002 in.) WC (0.49 Pa) to monitor the pressure difference across the sample.7.6 Pressure RegulatorPrecision regulator capable of delivering 1.0 standard litre per minute at pressures up to 3 bar.7.7 ULPA FilterRequired to remove ambient pa
44、rticles.7.8 Buna N or Nitrile Rubber SAE Standard AS 568A Size345 O-ringsProvide a seal between the challenge and filtrate sidesof the test.7.9 Precision AccumulatorTo minimize the effect of coincidence in the particle counters due to using high particleconcentrations when testing materials with hig
45、h filtration efficiency, the use of precision accumulators may be needed.AprecisionNOTE 1Dimensions of the cavity in mm. The configuration of the top and bottom cavity is identical.FIG. 2 Dimensions of the Sample CavityF2638 184accumulator is an inline vessel with a pre-determined volume sufficientl
46、y large enough to pull a representative sample of theparticle stream. The sample is then diluted using clean air to reduce the resulting concentration down to a level that is within theenumeration range of the particle counters.8. Materials8.1 Particle free, dry compressed air.8.2 Tween 20 or sodium
47、 dodecylsulfate (SDS).(SDS) or equivalent.8.3 Concentrate suspension of 1 m PSL particles (Duke Scientific 3K1000, 5100A, and G0100 have all been foundsatisfactory).8.4 DistilledPurified water sufficiently free of dissolved material. Reference USP Purified/Particle Free Standards.8.5 Porous packagin
48、g material.FIG. 3 Equipment Configuration for a Single Particle CounterMethod AF2638 1858.6 Ultrasonic bath.9. Apparatus Preparation9.1 Apparatus should be assembled as seen in Fig. 3 (single particle counter) or Fig. 4 (dual particle counter).9.2 Material Preparation:9.2.1 Surfactant Solution:9.2.1
49、.1 Prepare a 0.02 % v/v solution of surfactant (Tween 20, SDS, or equivalent) in distilled water daily.purified water dailyor as needed. The solution should be sonicated before use to ensure the elimination of aggregates of particles.NOTE 2It is important to eliminate bubbling in the preparation as the bubbles may interfere with the particle counts. If sonication results in excessivebubbling, mixing by other methods is acceptable.FIG. 4 Equipment Configuration for Dual Particle CountersMethod BF2638 1869.2.1.2 Aerosolize the surfac
