ASTM F2299/F2299M-03(2017)
(Test Method)Standard Test Method for Determining the Initial Efficiency of Materials Used in Medical Face Masks to Penetration by Particulates Using Latex Spheres
Standard Test Method for Determining the Initial Efficiency of Materials Used in Medical Face Masks to Penetration by Particulates Using Latex Spheres
SIGNIFICANCE AND USE
5.1 This test method measures the initial filtration efficiency of materials used in medical face masks by sampling representative volumes of the upstream and downstream latex aerosol concentrations in a controlled airflow chamber.
5.2 This test method provides specific test techniques for both manufacturers and users to evaluate materials when exposed to aerosol particle sizes between 0.1 and 5.0 μm.
5.2.1 This test method establishes a basis of efficiency comparison between medical face mask materials.
5.2.2 This test method does not establish a comprehensive characterization of the medical face mask material for a specific protective application.
5.3 This test method does not assess the overall effectiveness of medical face masks in preventing the inward leakage of harmful particles.
5.3.1 The design of the medical face mask and the integrity of the seal of the medical face mask to the wearer's face are not evaluated in this test.
5.4 This test method is not suitable for evaluating materials used in protective clothing for determining their effectiveness against particulate hazards.
5.4.1 In general, clothing design is a significant factor which must be considered in addition to the penetration of particulates.
SCOPE
1.1 This test method establishes procedures for measuring the initial particle filtration efficiency of materials used in medical facemasks using monodispersed aerosols.
1.1.1 This test method utilizes light scattering particle counting in the size range of 0.1 to 5.0 μm and airflow test velocities of 0.5 to 25 cm/s.
1.2 The test procedure measures filtration efficiency by comparing the particle count in the feed stream (upstream) to that in the filtrate (downstream).
1.3 The values stated in SI units or in other units shall be regarded separately as standard. The values stated in each system must be used independently of the other, without combining values in any way.
1.4 The following precautionary caveat pertains only to the test methods portion, Section 10, of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Buy Standard
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2299/F2299M − 03 (Reapproved 2017)
Standard Test Method for
Determining the Initial Efficiency of Materials Used in
Medical Face Masks to Penetration by Particulates Using
Latex Spheres
ThisstandardisissuedunderthefixeddesignationF2299/F2299M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1356Terminology Relating to Sampling and Analysis of
Atmospheres
1.1 This test method establishes procedures for measuring
D1777Test Method for Thickness of Textile Materials
the initial particle filtration efficiency of materials used in
D2905Practice for Statements on Number of Specimens for
medical facemasks using monodispersed aerosols.
Textiles (Withdrawn 2008)
1.1.1 This test method utilizes light scattering particle
D3776/D3776MTest Methods for Mass Per Unit Area
counting in the size range of 0.1 to 5.0 µm and airflow test
(Weight) of Fabric
velocities of 0.5 to 25 cm/s.
E691Practice for Conducting an Interlaboratory Study to
1.2 The test procedure measures filtration efficiency by
Determine the Precision of a Test Method
comparing the particle count in the feed stream (upstream) to
F50Practice for Continuous Sizing and Counting of Air-
that in the filtrate (downstream).
borne Particles in Dust-Controlled Areas and Clean
1.3 The values stated in SI units or in other units shall be Rooms Using Instruments Capable of Detecting Single
regarded separately as standard. The values stated in each
Sub-Micrometre and Larger Particles
system must be used independently of the other, without F328Practice for Calibration of anAirborne Particle Coun-
combining values in any way.
ter Using Monodisperse Spherical Particles (Withdrawn
2007)
1.4 The following precautionary caveat pertains only to the
F778Methods for Gas Flow ResistanceTesting of Filtration
test methods portion, Section 10, of this specification. This
Media
standard does not purport to address all of the safety concerns,
F1471Test Method for Air Cleaning Performance of a
if any, associated with its use. It is the responsibility of the user
High-Efficiency Particulate Air Filter System
of this standard to establish appropriate safety and health
F1494Terminology Relating to Protective Clothing
practices and determine the applicability of regulatory limita-
F2053Guide for Documenting the Results of Airborne
tions prior to use.
Particle Penetration Testing of Protective Clothing Mate-
1.5 This international standard was developed in accor-
rials
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 3. Terminology
mendations issued by the World Trade Organization Technical
3.1 Definitions:
Barriers to Trade (TBT) Committee.
3.1.1 aerosol, n—a suspension of a liquid or solid particles
in a gas with the particles being in the colloidal size range.
2. Referenced Documents
3.1.1.1 Discussion—In this test method, aerosols include
2.1 ASTM Standards:
solid particles having a diameter of 0.1 to 5 µm suspended or
dispersed in an airflow at concentrations of less than 102par-
ticles⁄cm .
ThistestmethodisunderthejurisdictionofASTMCommitteeF23onPersonal
ProtectiveClothingandEquipmentandisthedirectresponsibilityofSubcommittee
3.1.2 isokinetic sampling, n—aconditionwherethevelocity
F23.40 on Biological.
of the airflow entering the sampling nozzle is the same as the
Current edition approved June 1, 2017. Published June 2017. Originally
velocity of the airflow passing around the sampling nozzle.
approved in 2003. Last previous edition approved in 2010 as F2299/F2299M–03
(2010). DOI: 10.1520/F2299_F2299M-03R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2299/F2299M − 03 (2017)
3.1.3 monodispersion, n—scattering of discrete particles in 6.2.3 Aerosol generator,
anairflowwherethesizeiscentralizedaboutaspecificparticle 6.2.4 Charge neutralizer,
size. 6.2.5 Humidifier,
3.1.3.1 Discussion—In this test method, the monodispersed 6.2.6 Test filter holder and duct assembly,
particle distribution has a mean diameter size of the aerosol in 6.2.7 Pressure drop measuring device,
the 0.1 to 5 µm range, with a coefficient of variation of the 6.2.8 Air flow rate measuring device,
mean diameter of 610% or less, as certified by the manufac- 6.2.9 Temperature and relative humidity detectors,
turer. 6.2.10 Air blower (optional for negative pressure system),
and
3.2 Fordefinitionsofotherprotectiveclothing-relatedterms
6.2.11 Optical particle counters.
used in this test method, refer to Terminology F1494.
7. System Preparation and Control
4. Summary of Test Method
7.1 Totestintheaerosolparticlesizerangeof0.1to5.0µm,
4.1 Filtered and dried air is passed through an atomizer to
itisnecessarytomaintainaverycleaninletairsupply.Achieve
produce an aerosol containing suspended latex spheres.
acceptable levels of background aerosol by passing the atom-
4.1.1 This aerosol is then passed through a charge neutral-
izing air supply sequentially through a silica gel dryer (for
izer.
reductionofmoisture),amolecularsievematerial(forremoval
4.1.2 The aerosol is then mixed and diluted with additional
of oil vapor), and an ultra-low penetrating aerosol (better than
preconditioned air to produce a stable, neutralized, and dried
99.9999%efficientat0.6µm)filter.Then,supplytheairtothe
aerosol of latex spheres to be used in the efficiency test.
test chamber of aerosol generator through pressure regulators
of 67kPa[61psi]accuracy.Forthrottlingofthemainairflow
5. Significance and Use
as well as other flow splitting requirements, use needle valves
5.1 Thistestmethodmeasurestheinitialfiltrationefficiency
to maintain adequate flow stability and back pressure. For
of materials used in medical face masks by sampling represen-
recommended flow control measurement, see 7.6. Monitor and
tative volumes of the upstream and downstream latex aerosol
recordthetemperatureandrelativehumidityattheexhaustport
concentrations in a controlled airflow chamber.
ofthetestchamber.Toavoidinterferencefromthetestaerosol,
5.2 This test method provides specific test techniques for
take the humidity measurement from the outlet side of the
both manufacturers and users to evaluate materials when
HEPA filter (see 7.6.2) with an in-line probe.
exposed to aerosol particle sizes between 0.1 and 5.0 µm.
7.1.1 To provide a stable, reproducible aerosol through the
5.2.1 This test method establishes a basis of efficiency
test material that remains constant over the sampling time of
comparison between medical face mask materials.
the efficiency test, maintain the main test duct and filter
5.2.2 This test method does not establish a comprehensive
medium specimen holder in a vertical orientation to minimize
characterization of the medical face mask material for a
aerosol sedimentation losses.
specific protective application.
7.2 Aerosol Generation:
5.3 This test method does not assess the overall effective-
7.2.1 The aerosol generator must be capable of a latex
7 8 3
nessofmedicalfacemasksinpreventingtheinwardleakageof
sphere count concentrations output of 10 to 10 particles/m .
harmful particles.
The suspension reservoir must be large enough to sustain a
5.3.1 The design of the medical face mask and the integrity
stabilized output greater than 1 h. Two commercially available
ofthesealofthemedicalfacemasktothewearer’sfacearenot
atomizing techniques that provide these concentrations of the
evaluated in this test.
latex spheres are presented in Figs. 2 and 3.
7.2.2 AsviewedinFigs.2and3,thesetechniquesutilizethe
5.4 This test method is not suitable for evaluating materials
atomizing of suspended uniform latex spheres from dilute
used in protective clothing for determining their effectiveness
water suspensions. One-liter quantities of these suspensions
against particulate hazards.
can be made by diluting the 10%-by-volume solids of the
5.4.1 Ingeneral,clothingdesignisasignificantfactorwhich
uniform latex spheres at 1000:1 or greater dilution ratios in
must be considered in addition to the penetration of particu-
deionized, filtered distilled water.
lates.
NOTE 1—The suspensions have a three- to six-month usable life. Ideal
6. Apparatus
suspension dilutions are a function of the latex particle size to the aerosol
generatordropletsize.Inordertominimizetheatomizationofdoubletsor
6.1 The aerosol test system incorporates the components as
higher aerosol multiples in the drying process, a recommended latex
shown in Fig. 1. A more detailed diagram of test system
suspensiondilutionratiohasbeenestablishedsothatdilutionratiosareon
components and equipment is found in STP 975.
the order of 1000:1 to 10000:1. Other aerosols produced from these
atomizers can be classified into monodispersed systems, but for an
6.2 Equipment:
industrially recognized standard of particle size and composition, the
6.2.1 Clean, dry compressed air supply,
uniform latex spheres are the most reproducible and readily available
6.2.2 HEPA filters (2),
particles.
4 5
Symposium on Gas and Liquid Filtration, ASTM STP 975, ASTM, Vol 11, Raabe, O., “The Dilution of Monodispersed Suspensions for Aerosolization,”
1986, pp. 141-164. American Industrial Hygiene Association Journal, Vol 29, 1968, pp. 439–443.
F2299/F2299M − 03 (2017)
FIG. 1 Schematic of Test Method
7.3 Aerosol Neutralizer—This procedure recommends the system. This technique generally will ensure aerosol surface
use of an aerosol charge neutralizer at the inlet of the test charge stability.The aerosol neutralizer can be in the form of a
F2299/F2299M − 03 (2017)
FIG. 2 Atomizer
Complete the aerosol mixing a minimum of 8 duct diameters
distance before the inlet sampling probe and the material
specimen.
7.5 Material Specimen Holder:
7.5.1 The material specimen holder and test section shall be
a continuous straight-walled vessel, interrupted only by the
filter medium sample throughout its length. The material
specimen holder must provide an uninterrupted airflow, pas-
sage without measurable peripheral air leakage. Use a 50- to
150-mm [2- to 6-in.] cross-sectional diameter for the medium
sample size. Choose the specimen size to ensure that the test
specimen is representative of the overall material and provides
enough rigidity to be self-supporting.
NOTE 3—The recommended filter medium cross sections allow face
velocities of 0.5 to 25 cm/s [approximately 1 to 50 ft/min] at flow rates of
3 3
1 L/min to 1 m /min [approximately 0.035 to 35 ft /min] to be developed
FIG. 3 Collision Atomizer
in testing.
7.5.2 Introduce the latex aerosol a minimum of 10 duct
radioactive decay ionizer. The desired Boltzmann’s charge
diametersupstreamofthematerialspecimenandatasufficient
equilibrium for the aerosol has been described. Typically, an
distance to provide thorough mixing before the upstream
3 3
ionizing flux of 10 mCi/m /s provides the required aerosol
sampling probe.
neutralization.
NOTE 2—A Krypton 85 source, a Polonium 210 source, or a Corona 7.6 Airflow Metering:
electrical discharge, A-C source have been found satisfactory for this
7.6.1 Use a positive pressure (compressed air) or a negative
purpose.
pressure (exhaust fan or blower) system for the airflow to the
7.4 Aerosol Dilution and Humidity Control—Prior to injec-
main test chamber. For the application of any of these
tion or dispersion of the initial aerosol concentration into the
techniques of airflow measurement and calibration, refer to the
main test chamber, dry or dilute the aerosol with make-up
standardsandpracticesoftheAmericanSocietyofMechanical
airflow for the final test aerosol concentration as needed.
Engineers.
Conduct material testing in a relative humidity range of 30 to
7.6.2 Use a high efficiency particulate aerosol (HEPA)-type
50% and hold the relative humidity 65% during a given test.
filter (99.97% efficiency on 0.3-µm aerosol) upstream of the
systems airflow measurement. Size the HEPA-type filter to
6 provide adequate system collection of the exhausting test
Liu,B.Y.H.andPiu,D.Y.H.,“ElectricalNeutralizationofAerosols,” Aerosol
Science, Vol 5, 1974, pp. 465–472. aerosol.
F2299/F2299M − 03 (2017)
mounting volume are to be less than 10% of the total test system flow
7.7 Pressure Drop Measurement:
rate.
7.7.1 Use static pressure taps that are flush with the duct
7.9 Aerosol Concentration Counting:
walls at a distance of 1 duct diameter upstream and down-
stream of the filter medium faces. 7.9.1 This practice is structured for utilizing automatic,
single particle light-scattering counters. For an illustration of
7.7.2 Withnofiltermediuminthesampleholder,thereshall
the application, calibration, and analyses by these instruments,
be no measurable pressure loss between the inlet-side and
refer to Practices F50 and F328.
outlet-side pressure taps. Use a pressure-measuring instrument
7.9.2 Generally, single particle light-scattering counters
capable of being read to 60.025 cm of water gauge to make
measure in the range of 0.1 to 15 µm equivalent spherical
this determination.
diameter,withasingleparticlemeasurementdynamicrangeof
7.8 Aerosol Sample Extraction and Transport—Use geo-
50 to 1. These instruments shall be calibrated within the test
metrically and kinematically identical centerline probes to
system, similar to the manufacturer’s standard calibration and
extractrepresentativeaerosolsfromtheinletandoutletsidesof
with the test aerosol as conditioned for the efficiency testing.
the material specimen test section. Use probes that have a
For efficiencies approaching 99.9% and greater, a higher test
radius of curvature (R)of12cmor R/D (Diameter) > 20:1 and
inlet aerosol concentration is usually required to maintain
present a cross-sectional area of less than 10% of the cross-
reasonable sampling times at the outlet. If these conditions
sectional area of the test system ducting. Locate the upstream
exceed the
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F2299/F2299M − 03 (Reapproved 2017)
Standard Test Method for
Determining the Initial Efficiency of Materials Used in
Medical Face Masks to Penetration by Particulates Using
Latex Spheres
This standard is issued under the fixed designation F2299/F2299M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1356 Terminology Relating to Sampling and Analysis of
Atmospheres
1.1 This test method establishes procedures for measuring
D1777 Test Method for Thickness of Textile Materials
the initial particle filtration efficiency of materials used in
D2905 Practice for Statements on Number of Specimens for
medical facemasks using monodispersed aerosols.
Textiles (Withdrawn 2008)
1.1.1 This test method utilizes light scattering particle
D3776/D3776M Test Methods for Mass Per Unit Area
counting in the size range of 0.1 to 5.0 µm and airflow test
(Weight) of Fabric
velocities of 0.5 to 25 cm/s.
E691 Practice for Conducting an Interlaboratory Study to
1.2 The test procedure measures filtration efficiency by
Determine the Precision of a Test Method
comparing the particle count in the feed stream (upstream) to
F50 Practice for Continuous Sizing and Counting of Air-
that in the filtrate (downstream).
borne Particles in Dust-Controlled Areas and Clean
1.3 The values stated in SI units or in other units shall be
Rooms Using Instruments Capable of Detecting Single
regarded separately as standard. The values stated in each Sub-Micrometre and Larger Particles
system must be used independently of the other, without
F328 Practice for Calibration of an Airborne Particle Coun-
combining values in any way.
ter Using Monodisperse Spherical Particles (Withdrawn
2007)
1.4 The following precautionary caveat pertains only to the
F778 Methods for Gas Flow Resistance Testing of Filtration
test methods portion, Section 10, of this specification. This
Media
standard does not purport to address all of the safety concerns,
F1471 Test Method for Air Cleaning Performance of a
if any, associated with its use. It is the responsibility of the user
High-Efficiency Particulate Air Filter System
of this standard to establish appropriate safety and health
F1494 Terminology Relating to Protective Clothing
practices and determine the applicability of regulatory limita-
F2053 Guide for Documenting the Results of Airborne
tions prior to use.
Particle Penetration Testing of Protective Clothing Mate-
1.5 This international standard was developed in accor-
rials
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3. Terminology
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.1 Definitions:
Barriers to Trade (TBT) Committee.
3.1.1 aerosol, n—a suspension of a liquid or solid particles
in a gas with the particles being in the colloidal size range.
2. Referenced Documents
3.1.1.1 Discussion—In this test method, aerosols include
2.1 ASTM Standards:
solid particles having a diameter of 0.1 to 5 µm suspended or
dispersed in an airflow at concentrations of less than 102 par-
ticles ⁄cm .
This test method is under the jurisdiction of ASTM Committee F23 on Personal
Protective Clothing and Equipment and is the direct responsibility of Subcommittee
3.1.2 isokinetic sampling, n—a condition where the velocity
F23.40 on Biological.
of the airflow entering the sampling nozzle is the same as the
Current edition approved June 1, 2017. Published June 2017. Originally
velocity of the airflow passing around the sampling nozzle.
approved in 2003. Last previous edition approved in 2010 as F2299/F2299M – 03
(2010). DOI: 10.1520/F2299_F2299M-03R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2299/F2299M − 03 (2017)
3.1.3 monodispersion, n—scattering of discrete particles in 6.2.3 Aerosol generator,
an airflow where the size is centralized about a specific particle 6.2.4 Charge neutralizer,
size. 6.2.5 Humidifier,
3.1.3.1 Discussion—In this test method, the monodispersed 6.2.6 Test filter holder and duct assembly,
particle distribution has a mean diameter size of the aerosol in 6.2.7 Pressure drop measuring device,
the 0.1 to 5 µm range, with a coefficient of variation of the 6.2.8 Air flow rate measuring device,
mean diameter of 610 % or less, as certified by the manufac- 6.2.9 Temperature and relative humidity detectors,
turer. 6.2.10 Air blower (optional for negative pressure system),
and
3.2 For definitions of other protective clothing-related terms
6.2.11 Optical particle counters.
used in this test method, refer to Terminology F1494.
7. System Preparation and Control
4. Summary of Test Method
7.1 To test in the aerosol particle size range of 0.1 to 5.0 µm,
4.1 Filtered and dried air is passed through an atomizer to
it is necessary to maintain a very clean inlet air supply. Achieve
produce an aerosol containing suspended latex spheres.
acceptable levels of background aerosol by passing the atom-
4.1.1 This aerosol is then passed through a charge neutral-
izing air supply sequentially through a silica gel dryer (for
izer.
reduction of moisture), a molecular sieve material (for removal
4.1.2 The aerosol is then mixed and diluted with additional
of oil vapor), and an ultra-low penetrating aerosol (better than
preconditioned air to produce a stable, neutralized, and dried
99.9999 % efficient at 0.6 µm) filter. Then, supply the air to the
aerosol of latex spheres to be used in the efficiency test.
test chamber of aerosol generator through pressure regulators
of 67 kPa [61 psi] accuracy. For throttling of the main airflow
5. Significance and Use
as well as other flow splitting requirements, use needle valves
5.1 This test method measures the initial filtration efficiency
to maintain adequate flow stability and back pressure. For
of materials used in medical face masks by sampling represen-
recommended flow control measurement, see 7.6. Monitor and
tative volumes of the upstream and downstream latex aerosol
record the temperature and relative humidity at the exhaust port
concentrations in a controlled airflow chamber.
of the test chamber. To avoid interference from the test aerosol,
5.2 This test method provides specific test techniques for
take the humidity measurement from the outlet side of the
both manufacturers and users to evaluate materials when
HEPA filter (see 7.6.2) with an in-line probe.
exposed to aerosol particle sizes between 0.1 and 5.0 µm.
7.1.1 To provide a stable, reproducible aerosol through the
5.2.1 This test method establishes a basis of efficiency
test material that remains constant over the sampling time of
comparison between medical face mask materials.
the efficiency test, maintain the main test duct and filter
5.2.2 This test method does not establish a comprehensive
medium specimen holder in a vertical orientation to minimize
characterization of the medical face mask material for a
aerosol sedimentation losses.
specific protective application.
7.2 Aerosol Generation:
5.3 This test method does not assess the overall effective-
7.2.1 The aerosol generator must be capable of a latex
7 8 3
ness of medical face masks in preventing the inward leakage of
sphere count concentrations output of 10 to 10 particles/m .
harmful particles.
The suspension reservoir must be large enough to sustain a
5.3.1 The design of the medical face mask and the integrity
stabilized output greater than 1 h. Two commercially available
of the seal of the medical face mask to the wearer’s face are not
atomizing techniques that provide these concentrations of the
evaluated in this test.
latex spheres are presented in Figs. 2 and 3.
7.2.2 As viewed in Figs. 2 and 3, these techniques utilize the
5.4 This test method is not suitable for evaluating materials
atomizing of suspended uniform latex spheres from dilute
used in protective clothing for determining their effectiveness
water suspensions. One-liter quantities of these suspensions
against particulate hazards.
can be made by diluting the 10 %-by-volume solids of the
5.4.1 In general, clothing design is a significant factor which
uniform latex spheres at 1000:1 or greater dilution ratios in
must be considered in addition to the penetration of particu-
deionized, filtered distilled water.
lates.
NOTE 1—The suspensions have a three- to six-month usable life. Ideal
6. Apparatus
suspension dilutions are a function of the latex particle size to the aerosol
generator droplet size. In order to minimize the atomization of doublets or
6.1 The aerosol test system incorporates the components as
higher aerosol multiples in the drying process, a recommended latex
shown in Fig. 1. A more detailed diagram of test system
suspension dilution ratio has been established so that dilution ratios are on
components and equipment is found in STP 975.
the order of 1000:1 to 10 000:1. Other aerosols produced from these
atomizers can be classified into monodispersed systems, but for an
6.2 Equipment:
industrially recognized standard of particle size and composition, the
6.2.1 Clean, dry compressed air supply,
uniform latex spheres are the most reproducible and readily available
6.2.2 HEPA filters (2),
particles.
4 5
Symposium on Gas and Liquid Filtration, ASTM STP 975, ASTM, Vol 11, Raabe, O., “The Dilution of Monodispersed Suspensions for Aerosolization,”
1986, pp. 141-164. American Industrial Hygiene Association Journal, Vol 29, 1968, pp. 439–443.
F2299/F2299M − 03 (2017)
FIG. 1 Schematic of Test Method
7.3 Aerosol Neutralizer—This procedure recommends the system. This technique generally will ensure aerosol surface
use of an aerosol charge neutralizer at the inlet of the test charge stability. The aerosol neutralizer can be in the form of a
F2299/F2299M − 03 (2017)
FIG. 2 Atomizer
Complete the aerosol mixing a minimum of 8 duct diameters
distance before the inlet sampling probe and the material
specimen.
7.5 Material Specimen Holder:
7.5.1 The material specimen holder and test section shall be
a continuous straight-walled vessel, interrupted only by the
filter medium sample throughout its length. The material
specimen holder must provide an uninterrupted airflow, pas-
sage without measurable peripheral air leakage. Use a 50- to
150-mm [2- to 6-in.] cross-sectional diameter for the medium
sample size. Choose the specimen size to ensure that the test
specimen is representative of the overall material and provides
enough rigidity to be self-supporting.
NOTE 3—The recommended filter medium cross sections allow face
velocities of 0.5 to 25 cm/s [approximately 1 to 50 ft/min] at flow rates of
3 3
1 L/min to 1 m /min [approximately 0.035 to 35 ft /min] to be developed
FIG. 3 Collision Atomizer
in testing.
7.5.2 Introduce the latex aerosol a minimum of 10 duct
radioactive decay ionizer. The desired Boltzmann’s charge
diameters upstream of the material specimen and at a sufficient
equilibrium for the aerosol has been described. Typically, an
distance to provide thorough mixing before the upstream
3 3
ionizing flux of 10 mCi/m /s provides the required aerosol
sampling probe.
neutralization.
NOTE 2—A Krypton 85 source, a Polonium 210 source, or a Corona 7.6 Airflow Metering:
electrical discharge, A-C source have been found satisfactory for this
7.6.1 Use a positive pressure (compressed air) or a negative
purpose.
pressure (exhaust fan or blower) system for the airflow to the
7.4 Aerosol Dilution and Humidity Control—Prior to injec-
main test chamber. For the application of any of these
tion or dispersion of the initial aerosol concentration into the
techniques of airflow measurement and calibration, refer to the
main test chamber, dry or dilute the aerosol with make-up
standards and practices of the American Society of Mechanical
airflow for the final test aerosol concentration as needed.
Engineers.
Conduct material testing in a relative humidity range of 30 to
7.6.2 Use a high efficiency particulate aerosol (HEPA)-type
50 % and hold the relative humidity 65 % during a given test.
filter (99.97 % efficiency on 0.3-µm aerosol) upstream of the
systems airflow measurement. Size the HEPA-type filter to
provide adequate system collection of the exhausting test
Liu, B. Y. H. and Piu, D. Y. H., “Electrical Neutralization of Aerosols,” Aerosol
Science, Vol 5, 1974, pp. 465–472. aerosol.
F2299/F2299M − 03 (2017)
mounting volume are to be less than 10 % of the total test system flow
7.7 Pressure Drop Measurement:
rate.
7.7.1 Use static pressure taps that are flush with the duct
walls at a distance of 1 duct diameter upstream and down- 7.9 Aerosol Concentration Counting:
7.9.1 This practice is structured for utilizing automatic,
stream of the filter medium faces.
single particle light-scattering counters. For an illustration of
7.7.2 With no filter medium in the sample holder, there shall
the application, calibration, and analyses by these instruments,
be no measurable pressure loss between the inlet-side and
refer to Practices F50 and F328.
outlet-side pressure taps. Use a pressure-measuring instrument
7.9.2 Generally, single particle light-scattering counters
capable of being read to 60.025 cm of water gauge to make
measure in the range of 0.1 to 15 µm equivalent spherical
this determination.
diameter, with a single particle measurement dynamic range of
7.8 Aerosol Sample Extraction and Transport—Use geo-
50 to 1. These instruments shall be calibrated within the test
metrically and kinematically identical centerline probes to
system, similar to the manufacturer’s standard calibration and
extract representative aerosols from the inlet and outlet sides of
with the test aerosol as conditioned for the efficiency testing.
the material specimen test section. Use probes that have a
For efficiencies approaching 99.9 % and greater, a higher test
radius of curvature (R) of 12 cm or R/D (Diameter) > 20:1 and
inlet aerosol concentration is usually required to maintain
present a cross
...
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. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: F2299/F2299M − 03 (Reapproved 2010) F2299/F2299M − 03 (Reapproved
2017)
Standard Test Method for
Determining the Initial Efficiency of Materials Used in
Medical Face Masks to Penetration by Particulates Using
Latex Spheres
This standard is issued under the fixed designation F2299/F2299M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method establishes procedures for measuring the initial particle filtration efficiency of materials used in medical
facemasks using monodispersed aerosols.
1.1.1 This test method utilizes light scattering particle counting in the size range of 0.1 to 5.0 μm and airflow test velocities of
0.5 to 25 cm/s.
1.2 The test procedure measures filtration efficiency by comparing the particle count in the feed stream (upstream) to that in the
filtrate (downstream).
1.3 The values stated in SI units or in other units shall be regarded separately as standard. The values stated in each system must
be used independently of the other, without combining values in any way.
1.4 The following precautionary caveat pertains only to the test methods portion, Section 10, of this specification. This standard
does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this
standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D1777 Test Method for Thickness of Textile Materials
D2905 Practice for Statements on Number of Specimens for Textiles (Withdrawn 2008)
D3776D3776/D3776M Test Methods for Mass Per Unit Area (Weight) of Fabric
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F50 Practice for Continuous Sizing and Counting of Airborne Particles in Dust-Controlled Areas and Clean Rooms Using
Instruments Capable of Detecting Single Sub-Micrometre and Larger Particles
F328 Practice for Calibration of an Airborne Particle Counter Using Monodisperse Spherical Particles (Withdrawn 2007)
F778 Methods for Gas Flow Resistance Testing of Filtration Media
F1471 Test Method for Air Cleaning Performance of a High-Efficiency Particulate Air Filter System
F1494 Terminology Relating to Protective Clothing
F2053 Guide for Documenting the Results of Airborne Particle Penetration Testing of Protective Clothing Materials
3. Terminology
3.1 Definitions:
3.1.1 aerosol, n—a suspension of a liquid or solid particles in a gas with the particles being in the colloidal size range.
This test method is under the jurisdiction of ASTM Committee F23 on Personal Protective Clothing and Equipment and is the direct responsibility of Subcommittee
F23.40 on Biological.
Current edition approved June 1, 2010June 1, 2017. Published July 2010June 2017. Originally approved in 2003. Last previous edition approved in 20032010 as
F2299 - 03.F2299/F2299M – 03 (2010). DOI: 10.1520/F2299_F2299M-03R10.10.1520/F2299_F2299M-03R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2299/F2299M − 03 (2017)
3.1.1.1 Discussion—
In this test method, aerosols include solid particles having a diameter of 0.1 to 5 μm suspended or dispersed in an airflow at
concentrations of less than 102 102 particles particles/cm⁄cm .
3.1.2 isokinetic sampling, n—a condition where the velocity of the airflow entering the sampling nozzle is the same as the
velocity of the airflow passing around the sampling nozzle.
3.1.3 monodispersion, n—scattering of discrete particles in an airflow where the size is centralized about a specific particle size.
3.1.3.1 Discussion—
In this test method, the monodispersed particle distribution has a mean diameter size of the aerosol in the 0.1 to 5 μm range, with
a coefficient of variation of the mean diameter of 610 % or less, as certified by the manufacturer.
3.2 For definitions of other protective clothing-related terms used in this test method, refer to Terminology F1494.
4. Summary of Test Method
4.1 Filtered and dried air is passed through an atomizer to produce an aerosol containing suspended latex spheres.
4.1.1 This aerosol is then passed through a charge neutralizer.
4.1.2 The aerosol is then mixed and diluted with additional preconditioned air to produce a stable, neutralized, and dried aerosol
of latex spheres to be used in the efficiency test.
5. Significance and Use
5.1 This test method measures the initial filtration efficiency of materials used in medical face masks by sampling representative
volumes of the upstream and downstream latex aerosol concentrations in a controlled airflow chamber.
5.2 This test method provides specific test techniques for both manufacturers and users to evaluate materials when exposed to
aerosol particle sizes between 0.1 and 5.0 μm.
5.2.1 This test method establishes a basis of efficiency comparison between medical face mask materials.
5.2.2 This test method does not establish a comprehensive characterization of the medical face mask material for a specific
protective application.
5.3 This test method does not assess the overall effectiveness of medical face masks in preventing the inward leakage of harmful
particles.
5.3.1 The design of the medical face mask and the integrity of the seal of the medical face mask to the wearer’s face are not
evaluated in this test.
5.4 This test method is not suitable for evaluating materials used in protective clothing for determining their effectiveness
against particulate hazards.
5.4.1 In general, clothing design is a significant factor,factor which must be considered in addition to the penetration of
penetration of particulates.
6. Apparatus
6.1 The aerosol test system incorporates the components as shown in Fig. 1. A more detailed diagram of test system components
and equipment is found in STP 975.
6.2 Equipment:
6.2.1 Clean, dry compressed air supply,
6.2.2 HEPA filters (2),
6.2.3 Aerosol generator,
6.2.4 Charge neutralizer,
6.2.5 Humidifier,
6.2.6 Test filter holder and duct assembly,
6.2.7 Pressure drop measuring device,
6.2.8 Air flow rate measuring device,
6.2.9 Temperature and relative humidity detectors,
6.2.10 Air blower (optional for negative pressure system), and
6.2.11 Optical particle counters.
Symposium on Gas and Liquid Filtration, ASTM STP 975, ASTM, Vol 11, 1986, pp. 141-164.
F2299/F2299M − 03 (2017)
FIG. 1 Schematic of Test Method
7. System Preparation and Control
7.1 To test in the aerosol particle size range of 0.1 to 5.0 μm, it is necessary to maintain a very clean inlet air supply. Achieve
acceptable levels of background aerosol by passing the atomizing air supply sequentially through a silica-gel silica gel dryer (for
reduction of moisture), a molecular sieve material (for removal of oil vapor)vapor), and an ultra low ultra-low penetrating aerosol
(better than 99.9999 % efficient at 0.6 μm) filter. Then, supply the air to the test chamber of aerosol generator through pressure
regulators of 67 kPa [61 psi] accuracy. For throttling of the main airflow as well as other flow splitting requirements, use needle
valves to maintain adequate flow stability and back pressure. For recommended flow control measurement, see 7.6. Monitor and
F2299/F2299M − 03 (2017)
record the temperature and relative humidity at the exhaust port of the test chamber. To avoid interference from the test aerosol,
take the humidity measurement from the outlet side of the HEPA filter (see 7.6.2) with an in-line probe.
7.1.1 To provide a stable, reproducible aerosol through the test material that remains constant over the sampling time of the
efficiency test, maintain the main test duct and filter medium specimen holder in a vertical orientation to minimize aerosol
sedimentation losses.
7.2 Aerosol Generation:
7 8 3
7.2.1 The aerosol generator must be capable of a latex sphere count concentrations output of 10 to 10 particles/m . The
suspension reservoir must be large enough to sustain a stabilized output greater than 1 h. Two commercially available atomizing
techniques that provide these concentrations of the latex spheres are presented in Figs. 2 and 3.
7.2.2 As viewed in Figs. 2 and 3, these techniques utilize the atomizing of suspended uniform latex spheres from dilute water
suspensions. One liter One-liter quantities of these suspensions can be made by diluting the 10 % by volume 10 %-by-volume
solids of the uniform latex spheres at 1000 to 1 1000:1 or greater dilution ratios in deionized, filtered distilled water.
NOTE 1—The suspensions have a 3three- to 6 month six-month usable life. Ideal suspension dilutions are a function of the latex particle size to the
aerosol generator droplet size. In order to minimize the atomization of doublets or higher aerosol multiples in the drying process, a recommended latex
suspension dilution ratio has been established so that dilution ratios are on the order of 1000:1 to 10 000:1. Other aerosols produced from these atomizers
can be classified into monodispersed systems, but for an industrially recognized standard of particle size and composition, the uniform latex spheres are
the most reproducible and readily available particles.
7.3 Aerosol Neutralizer—This procedure recommends the use of an aerosol charge neutralizer at the inlet of the test system. This
technique generally will ensure aerosol surface charge stability. The aerosol neutralizer can be in the form of a radioactive decay
6 3
ionizer. The desired Boltzmann’s charge equilibrium for the aerosol has been described. Typically, an ionizing flux of 10
mCi/m /s provides the required aerosol neutralization.
NOTE 2—A Krypton 85 source, a Polonium 210 source, or a Corona electrical discharge, A-C source have been found satisfactory for this purpose.
7.4 Aerosol Dilution and Humidity Control—Prior to injection or dispersion of the initial aerosol concentration into the main
test chamber, dry or dilute the aerosol with make-up airflow for the final test aerosol concentration as needed. Conduct material
testing in a relative humidity range of 30 to 50 % and hold the relative humidity 65 % during a given test. Complete the aerosol
mixing a minimum of 8 duct diameters distance before the inlet sampling probe and the material specimen.
7.5 Material Specimen Holder:
7.5.1 The material specimen holder and test section shall be a continuous straight walled straight-walled vessel, interrupted only
by the filter medium sample throughout its length. The material specimen holder must provide an uninterrupted airflow, passage
without measurable peripheral air leakage. Use a 50 to 150 mm [2 to 6 in.] 50- to 150-mm [2- to 6-in.] cross-sectional diameter
Raabe, O., “The Dilution of Monodispersed Suspensions for Aerosolization,” American Industrial Hygiene Association Journal, Vol 29, 1968, pp. 439-443.439–443.
Liu, B. Y. H. and Piu, D. Y. H., “Electrical Neutralization of Aerosols,” Aerosol Science, Vol 5, 1974, pp. 465-472.465–472.
FIG. 2 Atomizer
F2299/F2299M − 03 (2017)
FIG. 3 Collision Atomizer
for the medium sample size. Choose the specimen size to ensure that the test specimen is representative of the overall material and
provides enough rigidity to be self-supporting.
NOTE 3—The recommended filter medium cross sections allow face velocities of 0.5 to 25 cm/s [approximately 1 to 50 ft/min] at flow rates of 1 L/min
3 3
to 1 m /min [approximately 0.035 to 35 ft /min] to be developed in testing.
7.5.2 Introduce the latex aerosol a minimum of 10 duct diameters upstream of the material specimen and at a sufficient distance
to provide thorough mixing before the upstream sampling probe.
7.6 Airflow Metering:
7.6.1 Use a positive pressure (compressed air) or a negative pressure (exhaust fan or blower) system for the airflow to the main
test chamber. For the application of any of these techniques of airflow measurement and calibration, refer to the standards and
practices of the American Society of Mechanical Engineers.
7.6.2 Use a High Efficiency Particulate Aerosol (HEPA) type high efficiency particulate aerosol (HEPA)-type filter (99.97 %
efficiency on 0.3 μm 0.3-μm aerosol) upstream of the systems airflow measurement. Size the HEPA type HEPA-type filter to
provide adequate system collection of the exhausting test aerosol.
F2299/F2299M − 03 (2017)
7.7 Pressure Drop Measurement:
7.7.1 Use static pressure taps that are flush with the duct walls at a distance of 1 duct diameter upstream and downstream of
the filter medium faces.
7.7.2 With no filter medium in the sample holder, there shall be no measurable pressure loss between the inlet-side and
outlet-side pressure taps. Use a pressure-measuring instrument capable of being read to 60.025 cm of water gauge to make this
determination.
7.8 Aerosol Sample Extraction and Transport—Use geometrically and kinematically identical centerline probes to extract
representative aerosols from the inlet and outlet sides of the material specimen test section. Use probes that have a radius of
curvature (R) of 12 cm or R/D (Diameter) > 20:1 and present a cross-sectional area of less than 10 % of the cross-sectional area
of the test system ducting. Locate the upstream probe 8 duct diameters (minimum) downstream of the aerosol injection point and
2 duct diameters ahead
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.