1、Designation: F 2101 07Standard Test Method forEvaluating the Bacterial Filtration Efficiency (BFE) ofMedical Face Mask Materials, Using a Biological Aerosol ofStaphylococcus aureus1This standard is issued under the fixed designation F 2101; the number immediately following the designation indicates
2、the year oforiginal 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.INTRODUCTIONWorkers, primarily those in the health care pro
3、fession, involved in treating and caring forindividuals injured or sick, as well as the patient, can be exposed to biological aerosols capable oftransmitting disease. These diseases, which may be caused by a variety of microorganisms, can posesignificant risks to life and health. Since engineering c
4、ontrols can not eliminate all possible exposures,attention is placed on reducing the potential of airborne exposure through the use of medical facemasks.1. Scope1.1 This test method is used to measure the bacterialfiltration efficiency (BFE) of medical face mask materials,employing a ratio of the up
5、stream bacterial challenge todownstream residual concentration to determine filtration effi-ciency of medical face mask materials.1.2 This test method is a quantitative method that allowsfiltration efficiency for medical face mask materials to bedetermined. The maximum filtration efficiency that can
6、 bedetermined by this method is 99.9 %.1.3 This test method does not apply to all forms or condi-tions of biological aerosol exposure. Users of the test methodshould review modes for worker exposure and assess theappropriateness of the method for their specific applications.1.4 This test method eval
7、uates medical face mask materialsas an item of protective clothing but does not evaluatematerials for regulatory approval as respirators. If respiratoryprotection for the wearer is needed, a NIOSH-certified respi-rator should be used. Relatively high bacterial filtration effi-ciency measurements for
8、 a particular medical face maskmaterial does not ensure that the wearer will be protected frombiological aerosols since this test method primarily evaluatesthe performance of the composite materials used in theconstruction of the medical face mask and not its design, fit orfacial sealing properties.
9、1.5 UnitsThe values stated in SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformance ofthe s
10、tandard.1.6 This test method does not address breathability of themedical face mask materials or any other properties affectingthe ease of breathing through the medical face mask material.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
11、theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 171 Specification for Atmospheres for Conditioning andTesting Flexible Barrier Mat
12、erialsF 1494 Terminology Relating to Protective Clothing2.2 ANSI/ASQC Standard:3ANSI/ASQC Z1.4 Sampling Procedures and Tables forInspection by Attributes1This test method is under the jurisdiction ofASTM Committee F23 on PersonalProtective Clothing and Equipment and is the direct responsibility of S
13、ubcommitteeF23.40 on Biological.Current edition approved Feb. 1, 2007. Published February 2007. Originallyapproved in 2001. Last previous edition approved in 2001 as F 2101 - 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org.
14、For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society for Quality (ASQ), 600 N. Plankinton Ave.,Milwaukee, WI 53203, http:/www.asq.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, We
15、st Conshohocken, PA 19428-2959, United States.2.3 ISO Standard:4ISO 2859-1 Sampling Plans for Inspection by Attributes2.4 Military Standard:5MIL-STD 36954C (1973) Military Specification: Mask,Surgical, Disposable3. Terminology3.1 Definitions:3.1.1 aerosol, na suspension of solid or liquid particles
16、ina gas.3.1.2 agar, na semi-solid culture medium used to supportthe growth of bacteria and other micro-organisms.3.1.3 airborne exposure pathways, ninhalation routes ofexposure to the medical face mask wearer.3.1.4 bacterial filtration effciency (BFE), nthe effective-ness of a medical face mask mate
17、rial in preventing the passageof aerosolized bacteria; expressed in the percentage of a knownquantity that does not pass the medical face mask material at agiven aerosol flow rate.3.1.5 biological aerosol, na suspension of particles con-taining biological agents which have been dispersed in a gas.3.
18、1.6 blood-borne pathogen, nan infectious bacterium orvirus, or other disease inducing microbe carried in blood orother potentially infectious body fluids.3.1.7 body fluid, nany liquid produced, secreted, or ex-creted by the human body.3.1.8 protective clothing, nan item of clothing that isspecifical
19、ly designed and constructed for the intended purposeof isolating all or part of the body from a potential hazard; or,isolating the external environment from contamination by thewearer of the clothing.3.1.9 medical face mask, nan item of protective clothingdesigned to protect portions of the wearers
20、face, including themucous membrane areas of the wearers nose and mouth, fromcontact with blood and other body fluids during medicalprocedures.3.1.9.1 DiscussionMedical face masks also function topartly limit the spread of biological contamination from themask wearer (health care provider) to the pat
21、ient.3.2 For definitions of other protective clothing-related termsused in this test method, refer to Terminology F 1494.4. Summary of Test Method4.1 The medical face mask material is clamped between asix-stage cascade impactor and an aerosol chamber. Thebacterial aerosol is introduced into the aero
22、sol chamber usinga nebulizer and a culture suspension of Staphylococcus aureus.The aerosol is drawn through the medical face mask materialusing a vacuum attached to the cascade impactor. The six-stagecascade impactor uses six agar plates to collect aerosol dropletswhich penetrate the medical face ma
23、sk material. Controlsamples are collected with no test specimen clamped in the testapparatus to determine the upstream aerosol counts.4.2 The agar plates from the cascade impactor are incubatedfor 48 h and counted to determine the number of viableparticles collected. The ratio of the upstream counts
24、 to thedownstream counts collected for the test specimen are calcu-lated and reported as a percent bacterial filtration efficiency.5. Significance and Use5.1 This test method offers a procedure for evaluation ofmedical face mask materials for bacterial filtration efficiency.This test method does not
25、 define acceptable levels of bacterialfiltration efficiency. Therefore, when using this test method it isnecessary to describe the specific condition under which testingis conducted.5.2 This test method has been specifically designed formeasuring bacterial filtration efficiency of medical face masks
26、,using Staphylococcus aureus as the challenge organism. Theuse of S. aureus is based on its clinical relevance as a leadingcause of nosocomial infections.5.3 This test method has been designed to introduce abacterial aerosol challenge to the test specimens at a flow rateof 28.3 L/mm. (1 ft3/min). Th
27、is flow rate is within the range ofnormal respiration and within the limitations of the cascadeimpactor.5.4 This test method allows the aerosol challenge to bedirected through either the face side or liner side of the testspecimen, thereby, allowing evaluation of filtration efficiencieswhich relate
28、to both patient-generated aerosols and wearer-generated aerosols.5.5 Degradation by physical, chemical, and thermal stressescould negatively impact the performance of the medical facemask material. The integrity of the material can also becompromised during use by such effects as flexing andabrasion
29、, or by wetting with contaminants such as alcohol andperspiration. Testing without these stresses could lead to a falsesense of security. If these conditions are of concern, evaluatethe performance of the medical face mask material for bacterialfiltration efficiency following an appropriate pretreat
30、ment tech-nique representative of the expected conditions of use. Con-sider preconditioning to assess the impact of storage conditionsand shelf life for disposable products, and the effects oflaundering and sterilization for reusable products.5.6 If this procedure is used for quality control, perfor
31、mproper statistical design and analysis of larger data sets. Thistype of analysis includes, but is not limited to, the number ofindividual specimens tested, the average percent bacterialfiltration efficiency, and standard deviation. Data reported inthis way help to establish confidence limits concer
32、ning productperformance. Examples of acceptable sampling plans are foundin references such as ANSI/ASQC Z1.4 and ISO 2859-1.6. Apparatus and Materials6.1 Apparatus:6.1.1 Autoclave, capable of maintaining 121-123C.6.1.2 Incubator, capable of maintaining 37 6 2C.6.1.3 Analytical Balance, capable of we
33、ighing 0.001 g.6.1.4 Vortex Mixer, capable of mixing the contents of 16mm 3 150 mm test tubes.6.1.5 Orbital Shaker, capable of achieving 100-250 rpm.6.1.6 Refrigerator, capable of maintaining 2-8C.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10
34、036, http:/www.ansi.org.5Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.F21010726.1.7 Six-Stage Viable Particle Cascade Impactor.6.1.8 Vacuum Pump, capable of 57 L/m (2 ft3/mm).6.1.9 Air Pump/Compressor, capable of 15
35、 psig minimum.6.1.10 Peristaltic Pump, capable of delivering 0.01 mL/min.6.1.11 Nebulizer, capable of delivering a mean particle sizeof 3.0 m 6 0.3 m and a challenge level of 2200 6 500 viableparticles per test, as determined according to step 12.3.6.1.12 Glass Aerosol Chamber, 60 cm by 8 cm diamete
36、rtube.6.1.13 Colony Counter, manual or automatic, capable ofcounting up to 400 colonies/plate.6.1.14 Timers, capable of 0.1 s accuracy.6.1.15 Automatic Pipetor, capable of delivering 1.0 mL 60.05 mL.6.1.16 Flow Meters, capable of 28.3 L/min.6.1.17 Aerosol Condenser.6.1.18 Pressure Gauge, capable of
37、35 kPa 6 1 kPa accu-racy.6.1.19 Air Regulator.6.2 Materials:6.2.1 Flasks, 250-500 mL Erlenmeyer.6.2.2 Petri Dishes, sterile 15 by 100 mm.6.2.3 Pipettes, 1 mL, 5 mL, and 10 mL.6.2.4 Test Tube Rack, stainless6.2.5 Bottles, sterile, glass, 100-500 mL capacity.6.2.6 Inoculating Loop.6.2.7 Stoppers/Closu
38、res, of appropriate size to fit test tubes.6.2.8 Test Tubes,16mm3 150 mm.7. Reagents7.1 Tryptic Soy Agar TSA6.7.2 Tryptic Soy Broth TSB6.7.3 Peptone Water6.7.4 Staphylococcus aureus, ATCC #65388. Hazards8.1 Sterilize all apparatus and supplies which come intocontact with the bacterial challenge susp
39、ension, by autoclavingat 121-123 C for a minimum of 15 min. Extreme care must betaken to avoid contamination of the laboratory spaces bycomplete sterilization or high level disinfection of all apparatusand supplies. This will reduce the possibility of laboratorycontamination.8.2 Staphylococcus aureu
40、s is common to the normal floraof the body, however, it is a leading cause of nosocomialinfections and is a human pathogen. Technicians conductingthe testing must have proper microbiological training. Glovesand other protective clothing equipment should be worn duringtesting to prevent contamination
41、.8.3 All aerosols must be contained to prevent exposure andreduce laboratory contamination.9. Media Preparation9.1 Prepare media using standard microbiological tech-niques.9.2 Prepare agar plates for cascade impactor as specified bythe manufacturer of the cascade impactor.10. Test Specimen10.1 Test
42、specimens shall be taken from manufacturedmedical face masks, with all layers arranged in proper order.11. Conditioning11.1 Condition each specimen for a minimum of4hbyexposure to a temperature of 21 6 5C(706 10F) andrelative humidity of 85 6 5 % as described in SpecificationE 171 using a controlled
43、 temperature and humidity chamber orspace.12. Preparation of the Bacterial Challenge12.1 Inoculate an appropriate volume of tryptic soy brothwith and incubate with mild shaking at 37 6 2C for 24 6 2h.12.2 Dilute the culture in peptone water to achieve aconcentration of approximately 5 3 105CFU/mL.12
44、.3 The challenge delivery rate will be maintained at 22006 500 viable particles per test. The challenge delivery rate isdetermined each day of testing and is based on the results of thepositive control plates when the aerosol is collected in asix-stage viable particle cascade impactor, with no test
45、speci-men clamped into the test system. The dilution of the challengesuspension will need to be adjusted to deliver the properchallenge level during testing.13. Test Procedure13.1 The aerosol challenge apparatus is outlined in Fig. 1.13.2 Deliver the challenge to the nebulizer using a peristal-tic o
46、r syringe pump. Connect tubing to nebulizer and peristalticpump and into the challenge suspension; purge tubing andnebulizer of air bubbles.NOTE 1The peristaltic pump or syringe pump must be calibrated todeliver a consistent challenge volume throughout the testing interval.13.3 Perform a positive co
47、ntrol run without a test specimenclamped into the test system to determine the number of viableaerosol particles being generated. The mean particle size(MPS) of the aerosol will also be calculated from the results ofthese positive control plates.13.4 Initiate the aerosol challenge by turning on the
48、airpressure and pump connected to the nebulizer.13.5 Immediately begin sampling the aerosol using thecascade impactor. Adjust the flow rate through the cascadeimpactor to 28.3 L/m.13.6 Time the challenge suspension to be delivered to thenebulizer for 1 min.13.7 Time the air pressure and cascade impa
49、ctor to run for2 min.13.8 At the conclusion of the positive control ran, removeplates from the cascade impactor. Label each plate with thecorresponding stage number.6The sole source of supply of the apparatus known to the committee at this timeis Difco, Detroit, MI 48232. If you are aware of alternative suppliers, please providethis information to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.F210107313.9 Place new agar plates into the cascade impact
