ASTM F51/F51M-20

Standard Test Method for Sizing and Counting Particulate Contaminant In and On Clean Room Garments

SIGNIFICANCE AND USE
5.1 The test method for particulate sizing and numbers on garments is nondestructive and may be used to evaluate the contamination levels of fibers and particles on and in clean room garments. The test may be used for evaluating the cleanliness levels of new or newly cleaned garments. It also may be used to evaluate the extent of fiber and particulate contamination on garments that have been worn, if necessary. For this application, it is necessary to sample representative areas of the garment fabric.
SCOPE
1.1 This test method covers the determination of detachable particulate contaminant 5 μm or larger, in and on the fabric of clean room garments.  
1.2 This test method does not apply to nonporous fabrics such as Tyvek (trademarked) or Gortex (trademarked). It only applies to fabrics that are porous such as cotton or polyester.  
1.3 This test method provides not only the traditional optical microscopic analysis but also a size distribution and surface obscuration analysis for particles on a fine-textured membrane filter or in a tape lift sample. It utilizes transmitted illumination to render all particles darker than the background for gray level detection. Particles collected on opaque plates must be transferred to a suitable membrane filter.  
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.5 This standard may involve hazardous materials, operations, and equipment. 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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

• Status: Published
• Publication Date: 31-Mar-2020
• ICS: 61.020 - Clothes
• Technical Committee: E21 - Space Simulation and Applications of Space Technology
• Drafting Committee: E21.05 - Contamination

Relations

• Replaces: ASTM F51/F51M-00(2014)e1 - Standard Test Method for Sizing and Counting Particulate Contaminant In and On Clean Room Garments
• Effective Date: 01-Apr-2020
• Refers: ASTM E1216-11 - Standard Practice for Sampling for Particulate Contamination by Tape Lift
• Effective Date: 01-Sep-2011
• Refers: ASTM F25/F25M-09 - Standard Test Method for Sizing and Counting Airborne Particulate Contamination in Cleanrooms and Other Dust-Controlled Areas
• Effective Date: 01-Apr-2009
• Refers: ASTM E1216-06 - Standard Practice for Sampling for Particulate Contamination by Tape Lift
• Effective Date: 01-Apr-2006
• Refers: ASTM E1216-99(2005) - Standard Practice for Sampling for Particulate Contamination by Tape Lift
• Effective Date: 01-Apr-2005
• Refers: ASTM E1216-99 - Standard Practice for Sampling for Particulate Contamination by Tape Lift
• Effective Date: 10-Oct-1999

Overview

ASTM F51/F51M-20 is the internationally recognized standard test method for sizing and counting particulate contaminants in and on clean room garments. Developed by ASTM International, this standard offers a nondestructive approach to assess fiber and particle contamination levels on porous clean room apparel such as cotton or polyester. The method is critical for industries where environmental cleanliness is paramount, including semiconductor, pharmaceutical, biotechnology, and aerospace sectors.

This standard enables organizations to evaluate both new and laundered clean room garments, as well as apparel worn in controlled environments, ensuring continued control over contamination sources that could compromise sensitive processes or products.

Key Topics

• Scope of Application

  • Applies to clean room garments made from porous fabrics (e.g., cotton, polyester).
  • Excludes nonporous fabrics like Tyvek® or Gore-Tex®.
  • Focuses on detachable particulate contaminants 5 micrometers (μm) or larger.

• Test Methodology

  • Utilizes both optical microscopic analysis and automated image analysis for particle sizing and counting.
  • Involves sampling five designated areas per garment, drawing filtered air through the fabric to collect contaminants on a membrane filter.
  • Provides data on particle size distribution and surface obscuration.

• Reporting Units

  • Results are stated in either SI units or inch-pound units, to be used independently according to project requirements.

• Safety Considerations

  • Users are responsible for adopting suitable safety, health, and environmental practices due to potential hazards in test operations.
  • Regulatory compliance must be verified for all relevant procedures and materials.

Applications

• Clean Room Apparel Qualification

  • Assess the cleanliness of new or freshly cleaned garments prior to introduction into controlled environments.
  • Evaluate contamination on garments returned from service to determine continued suitability or laundering effectiveness.

• Routine Quality Control

  • Implement a repeatable, objective method in clean room garment processing facilities to ensure garments meet strict contamination criteria for critical operations.

• Garment Classification

  • Use test data to classify and compare clean room garments by contamination class, supporting standardized inventory control and regulatory documentation.

• Process Validation

  • Support validation studies for cleaning and garment-handling processes within pharmaceutical, biotech, electronics, and other high-purity manufacturing sites.

Related Standards

• ASTM E1216 - Practice for Sampling for Particulate Contamination by Tape Lift: Provides additional recommendations and methodology for tape lift sampling.
• ASTM F25/F25M - Test Method for Sizing and Counting Airborne Particulate Contamination in Cleanrooms: Complements F51/F51M by addressing airborne particles rather than garment-borne contaminants.
• IEST-RP-CC003.2 - Garment System Considerations for Cleanrooms: Offers broader guidance on garment systems used in controlled environments.
• World Trade Organization (WTO) TBT Committee Principles - Ensures standardization aligns with global trade and technical barriers requirements.

Practical Value

Adhering to ASTM F51/F51M-20 provides:

• Reliable, reproducible measurements of particulate contamination on clean room garments.
• Protection of product quality in contamination-sensitive sectors.
• Support for regulatory compliance and certification.
• Improved decision-making for garment selection and cleaning validation.

By using this standard, industries reinforce their commitment to clean manufacturing and contamination control, reducing defects, improving yields, and safeguarding sensitive products and processes.

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: F51/F51M − 20
Standard Test Method for
Sizing and Counting Particulate Contaminant In and On
Clean Room Garments
This standard is issued under the fixed designation F51/F51M; the number immediately following the designation indicates the year 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the determination of detachable
E1216Practice for Sampling for Particulate Contamination
particulate contaminant 5µm or larger, in and on the fabric of
by Tape Lift
clean room garments.
F25/F25MTest Method for Sizing and Counting Airborne
1.2 This test method does not apply to nonporous fabrics
ParticulateContaminationinCleanroomsandOtherDust-
such as Tyvek (trademarked) or Gortex (trademarked). It only
Controlled Areas
applies to fabrics that are porous such as cotton or polyester.
2.2 IEST Document:
1.3 Thistestmethodprovidesnotonlythetraditionaloptical
IEST-RP-CC003.2, Garment System Considerations for
microscopic analysis but also a size distribution and surface
Cleanrooms and Other Controlled Environments
obscuration analysis for particles on a fine-textured membrane
filterorinatapeliftsample.Itutilizestransmittedillumination
3. Terminology
torenderallparticlesdarkerthanthebackgroundforgraylevel
3.1 Definitions:
detection. Particles collected on opaque plates must be trans-
3.1.1 fiber, n—particle longer than 100 µm and with a
ferred to a suitable membrane filter.
length-to-width ratio exceeding 10:1.
-6
1.4 Units—The values stated in either SI units or inch-
3.1.2 micrometre (µm), n—SIunitoflengthwhichis10 of
pound units are to be regarded separately as standard. The
a metre or approximately 0.00004 in.
values stated in each system are not necessarily exact equiva-
3.1.3 particle size (L) (µm), n—major projected dimension
lents; therefore, to ensure conformance with the standard, each
of a particle.
system shall be used independently of the other, and values
from the two systems shall not be combined.
4. Summary of Test Method
1.5 This standard may involve hazardous materials, 2
4.1 Filtered air is drawn through five designated 0.01m
operations, and equipment. This standard does not purport to
2 2
[1.5in. or approximately 0.01ft ] areas of a single thickness
address all of the safety concerns, if any, associated with its
of the garment fabric at a rate of 14 L/min [0.5 cfm] for a
use. It is the responsibility of the user of this standard to
period of 1 min for each area.
establish appropriate safety, health, and environmental prac-
4.2 The air drawn through the garment subsequently passes
tices and determine the applicability of regulatory limitations
through a membrane filter disk, impinging the entrained
prior to use.
particles upon the filter surface.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard- 4.3 The filter disk is then examined microscopically for
particles removed from the garment.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4.4 For particles larger than 5 µm, use optical analysis. For
mendations issued by the World Trade Organization Technical
particles smaller than 5 µm, use automated image analysis.
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is under the jurisdiction of ASTM Committee E21 on Space contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Simulation andApplications of SpaceTechnology and is the direct responsibility of Standards volume information, refer to the standard’s Document Summary page on
Subcommittee E21.05 on Contamination. the ASTM website.
Current edition approved April 1, 2020. Published May 2020. Originally Available from Institute of Environmental Sciences and Technology (IEST),
approved in 1965. Last previous edition approved in 2014 as F51/ Arlington Place One, 2340 S.Arlington Heights Rd., Suite 100,Arlington Heights,
ε1
F51M –00(2014) . DOI: 10.1520/F0051_F0051M-20. IL 60005-4516, http://www.iest.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F51/F51M − 20
FIG. 1 Filter Assembly
FIG. 2 Adapter
4.5 Cleaning and counting techniques are in accordance 6.4.4 Plastic Petri Slides with Covers , plastic petri dishes,
with those established in Section 10. 60mm diameter or glass microscope slides, 50 by 75 mm.
6.5 Binocular Microscope, with ocular-objective combina-
5. Significance and Use
tionstoobtain40to45×and90to150×magnifications.Latter
objective shall have a numerical aperture of 0.15 min.
5.1 The test method for particulate sizing and numbers on
garments is nondestructive and may be used to evaluate the
6.6 Programmable Image Analyzer, a Computer-Driven Mi-
contamination levels of fibers and particles on and in clean
croscope Which Counts and Sizes Particles With Automated
room garments. The test may be used for evaluating the
Stage and Automated Focus Interface:
cleanliness levels of new or newly cleaned garments. It also
6.6.1 Microscope, with a large glass platform automatic
may be used to evaluate the extent of fiber and particulate
stage and automated focus.
contamination on garments that have been worn, if necessary.
6.6.2 Objectives and Projection Lenses, to generate a pixel
For this application, it is necessary to sample representative
dimension of about 5 µm or less.
areas of the garment fabric.
6.7 Forceps, with unserrated tips.
6.8 Normal Counter, (2 gang) or equivalent. See Note 1.
6. Apparatus
NOTE 1—The Veeder Root counter has been found satisfactory for this
6.1 Filter Assembly and Adapter, see Fig. 1 and Fig. 2.
purpose.
6.1.1 Filter Holder, aerosol open type having an effective
6.9 Microscope Lamp, 6 V, 5 A high intensity.
filter area of 960 6 25 mm .
6.10 Stage Micrometer, standard 0.01 to 0.1mm scale.
6.2 Vacuum Pump or Aspirator, capable of operating at a
pressure of 7 kPa [500 torr] with a flow rate of 14L⁄min 6.11 Ocular Micrometer Scale, 5mm linear scale with 100
[0.5cfm]. divisions.
6.12 Standard Counting Specimens.
6.3 Flowmeter or Orifice, calibrated and having a capacity
inexcessof14L/min[0.5cfm],oralimitingorificecalibrated
7. Sampling Requirements
withthepump,filterholder,andfilterusedforthistestmethod
at a flow rate of 14 6 0.5 L/min [0.50 6 0.02 cfm]. Ensure,
7.1 The sample shall be collected by drawing air filtered to
visually, that the orifice is free of obstructing matter before 5 µm through the test garment, impinging the garment-borne
each test.
particles on the membrane filter. The filter surface mounted in
the open-type aerosol filter holder shall be placed on the outer
6.4 Membrane Filters:
surface of the test garment. The garment is firmly clamped to
6.4.1 Black, 0.80µm pore size, 47mm diameter with
the filter holder by means of the air-filter adapter. During
3.08mm imprinted grid for fabric particles.
6.4.2 White, 0.80µm pore size, 47mm diameter without
imprinted grid for fabric particles and automated image ana- The sole source of supply of the apparatus (Analyslides) known to the
committee at this time is Pall Corporation, Port Washington, NY. If you are aware
lyzer.
of alternative suppliers, please provide this information to ASTM International
6.4.3 White, 5.0µm pore size, 47mm diameter (air prefilter
Headquarters.Your comments will receive careful consideration at a meeting of the
used with the filters in 6.4.1 and 6.4.2). responsible technical committee, which you may attend.
F51/F51M − 20
FIG. 3 Clean Room Garment Sampling Locations
sampling, the garment shall be hung or carefully positioned to 8.4 Cleanandpreparethemicroscopeslidesandpetridishes
minimize extraneous contamination. for preserving the membrane filter and specimen. Lens tissue
properly used is satisfactory for this operation.
7.2 The standard sample of this test method is secured with
thepassageof14L[0.5ft ]ofairthroughthetestfabricduring
8.5 Handle hazardous chemicals used in the test method
a 1min period at each of five sampling areas as shown in Fig. with recognized precautions.
3. One sampling area is adequate for caps, helmets, towels,
8.6 Establish a background count on membrane filters by
wipers,andbootieswithplasticsoles.Twoareasaresuggested
examiningeachfilterusedforrefereepurposes.Examinationat
for all-fabric booties.
40 to 50× magnifications through the microscope will reveal
7.3 Locations are approximate and may be modified to suit
low or high background count.
a specific design factor by agreement.
8.7 Make a background count (Note 2) following the
microscopic methods outlined in this test method, upon any
8. Preparation of Apparatus
filterwithacontaminationlevelapproximating10%orgreater
8.1 Beforesamplingwhenusingonlyamicroscope,remove
of the estimated test sample (Note 3). This count will be
dirtanddustfromthefilterholderbywashinginafree-rinsing
subtracted from the total count (P) obtained in 10.1 for each
t
detergent, ketone-free, isopropyl alcohol and submicrometer-
size range.
filteredreagentgradepetroleumether(boilingrangefrom30to
8.8 Place acceptable filters in clean petri dishes and cover.
60°C).
Identify the dishes for test use.
8.2 Maintain the laboratory equipment and area used for
8.9 Whenusinganautomatedimageanalyzer,preparationis
counting and sizing the particles in a condition of cleanliness
similar to the preceding except that the white, ungridded
parallel or superior to the area sampled. Good clean room and
0.08µm filter is used.
contamination control practices should be followed. Plastic
microscope hoods have proven satisfactory as covering, in a
NOTE 2—For routine work, a background count on two filters per box
clean room, in the absence of a laboratory clean hood. of 100 is adequate under present rigid production methods.
NOTE 3—If the background count is estimated to be greater than 10%
8.3 Personnel performing sizing and counting operations
3 3
of the total count from a 0.3m [10ft ] specimen, a larger sample 0.4 or
3 3
shall wear garments and behave in a manner appropriate to the
0.6m [15 to 20ft ] volume may be used to eliminate background count
cleanliness conditions in which they are working. procedure.
F51/F51M − 20
FIG. 5 Placing the Filter on a Typical Screen Support
FIG. 4 Inserting a Typical Orifice
9. Sampling
9.1 With the aid of laboratory pressure tubing, connect the
filter holder to a source of vacuum which has been found
adequate to produce a flow rate of 14 L/min [0.5 cfm], at
vacuum conditions test (pressure of 5 kPa or 350 torr). The
holder may be open, may contain a limiting orifice (Fig. 4), or
may be connected to the flowmeter. If a flowmeter is used
between the filter holder and vacuum source, correction to the
standard temperature and pressure must be made to determine
actual standard temperature and pressure flow.
9.2 With clean forceps, carefully remove the appropriate
membrane filter from the container and place, with grid side
up, when appropriate, on the screen support of the filter holder
(Fig. 5). Twist the locking ring in place after placing the
taperedadapterinposition.Similarly,placethe5.0µmairfilter
in the top portion of the adapter by removing the O-ring from
the adapter top, placing a 47mm white filter on the support
screen and replacing the O-ring. (This filter may be used for
FIG. 6 Typical Counting and Sizing Microscope and Illuminator
many tests.)
(see Test Method F25/F25M)
9.3 See IEST-RP-CC003.2 for additional recommendations
on the sampling of garments.
10.2 Knowing the subdivisions of the stage micrometer
9.4 Whenreadytosample,placetheoutersurfaceofthetest
(top),thedivisionsofthemeasuringeyepiece(bottom)maybe
garment over the tapered (male) adapter. Firmly lock into test
sized from it (Fig. 7).
position by placing the air-filter tapered (female) adapter over
NOTE4—Example:Stagethemicrometer100µmpermajordivision,10
the test portion of fabric.
µm per minor division: 100 divisions of the measuring eyepiece subtend
9.5 Apply vacuum at the predetermined flow rate of 14
1050 µm, one division of the measuring eyepiece = 10.5 µm.
L/min [0.5 cfm] for a period of 1 min for each area. Sample
10.3 Remove the petri dish cover, then remove the filter
required areas (Fig. 3) by repeating 9.2.
from the petri dish and place it, with filtering surface up, on a
9.6 Removethefilterfromtheholderwithforcepsandplace 50 by 76mm [2 by 3in.] microscope slide. Greasing the slide
it between the clean microscope slides, in a clean transport lightly with silicone stopcock lubricant before mountin
...

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.
´1
Designation: F51/F51M − 00 (Reapproved 2014) F51/F51M − 20
Standard Test Method for
Sizing and Counting Particulate Contaminant In and On
Clean Room Garments
This standard is issued under the fixed designation F51/F51M; 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.
ε NOTE—Editorial changes were made throughout in March 2013.
1. Scope
1.1 This test method covers the determination of detachable particulate contaminant 5 μm 5 μm or larger, in and on the fabric
of clean room garments.
1.2 This test method does not apply to nonporous fabrics such as Tyvek (trademarked) or Gortex (trademarked). It only applies
to fabrics that are porous such as cotton or polyester.
1.3 This test method provides not only the traditional optical microscopic analysis but also a size distribution and surface
obscuration analysis for particles on a fine-textured membrane filter or in a tape lift sample. It utilizes transmitted illumination to
render all particles darker than the background for gray level detection. Particles collected on opaque plates must be transferred
to a suitable membrane filter.
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated
in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
1.5 This standard may involve hazardous materials, operations, and equipment. 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 safety, health, and healthenvironmental practices and determine the applicability of regulatory limitations prior to use.
1.6 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:
E1216 Practice for Sampling for Particulate Contamination by Tape Lift
F25/F25M Test Method for Sizing and Counting Airborne Particulate Contamination in Cleanrooms and Other Dust-Controlled
Areas
2.2 Institute of Environmental Sciences and Technology (IEST) IEST Document:
IEST-RP-CC003.2, Garment System Considerations for Cleanrooms and Other Controlled Environments
3. Terminology
3.1 Definitions:
3.1.1 fiber, n—particle longer than 100 μm and with a length-to-width ratio exceeding 10:1.
-6
3.1.2 micrometre (μm), n—SI unit of length which is 10 of a metre or approximately 0.00004 in.
3.1.3 particle size (L) (μm)—), n—major projected dimension of a particle.
This test method is under the jurisdiction of ASTM Committee E21 on Space Simulation and Applications of Space Technology and is the direct responsibility of
Subcommittee E21.05 on Contamination.
Current edition approved Jan. 15, 2014April 1, 2020. Published February 2014May 2020. Originally approved in 1965. Last previous edition approved in 20072014 as
ε1
F51 - 00F51/F51M(2007) – 00(2014) . DOI: 10.1520/F0051_F0051M-00R14E01.10.1520/F0051_F0051M-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Institute of Environmental Sciences and Technology (IEST), Arlington Place One, 2340 S. Arlington Heights Rd., Suite 100, Arlington Heights, IL
60005-4516, http://www.iest.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F51/F51M − 20
FIG. 1 Filter Assembly
4. Summary of Test Method
2 2 2
4.1 Filtered air is drawn through five designated 0.01-m0.01 m [1.5-in.[1.5 in. or approximately 0.01-ft0.01 ft ] areas of a
single thickness of the garment fabric at a rate of 14 L/min [0.5 cfm] for a period of 1 min for each area.
4.2 The air drawn through the garment subsequently passes through a membrane filter disk, impinging the entrained particles
upon the filter surface.
4.3 The filter disk is then examined microscopically for particles removed from the garment.
4.4 For particles larger than 5 μm, use optical analysis. For particles smaller than 5 μm, use automated image analysis.
4.5 Cleaning and counting techniques are in accordance with those established in Section 10.
5. Significance and Use
5.1 The test method for particulate sizing and numbers on garments is nondestructive and may be used to evaluate the
contamination levels of fibers and particles on and in clean room garments. The test may be used for evaluating the cleanliness
levels of new or newly cleaned garments. It also may be used to evaluate the extent of fiber and particulate contamination on
garments that have been worn, if necessary. For this application, it is necessary to sample representative areas of the garment fabric.
6. Apparatus
6.1 Filter Assembly and Adapter, see Fig. 1 and Fig. 2.
6.1.1 Filter Holder, aerosol open type having an effective filter area of 960 6 25 mm .
6.2 Vacuum Pump or Aspirator, capable of operating at a pressure of 7 kPa [500 torr] with a flow rate of 1414 L L/min [0.5
cfm].⁄min [0.5 cfm].
6.3 Flowmeter or Orifice, calibrated and having a capacity in excess of 14 L/min [0.5 cfm], or a limiting orifice calibrated with
the pump, filter holder, and filter used for this test method at a flow rate of 14 6 0.5 L/min [0.50 6 0.02 cfm]. Ensure, visually,
that the orifice is free of obstructing matter before each test.
6.4 Membrane Filters:
6.4.1 Black, 0.80-μm0.80 μm pore size, 47-mm47 mm diameter with 3.08-mm3.08 mm imprinted grid for fabric particles.
6.4.2 White, 0.80-μm0.80 μm pore size, 47-mm47 mm diameter without imprinted grid for fabric particles and automated image
analyzer.
6.4.3 White, 5.0-μm5.0 μm pore size, 47-mm47 mm diameter (air prefilter used with the filters in 6.4.1 and 6.4.2).
6.4.4 Plastic Petri Slides with Covers , plastic petri dishes, 60-mm60 mm diameter or glass microscope slides, 50 by 75 mm.
6.5 Binocular Microscope, with ocular-objective combinations to obtain 40 to 45× and 90 to 150× magnifications. Latter
objective shall have a numerical aperture of 0.15 min.
The sole source of supply of the apparatus (Analyslides) known to the committee at this time is Gelman Sciences, Ann Arbor, MI.Pall Corporation, Port Washington,
NY. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
F51/F51M − 20
FIG. 2 Adapter
6.6 Programmable Image Analyzer, a Computer-Driven Microscope Which Counts and Sizes Particles With Automated Stage
and Automated Focus Interface:
6.6.1 Microscope, with a large glass platform automatic stage and automated focus.
6.6.2 Objectives and Projection Lenses, to generate a pixel dimension of about 5 μm or less.
6.7 Forceps, with unserrated tips.
6.8 Normal Counter, (2 gang) or equivalent. See Note 1.
NOTE 1—The Veeder Root counter has been found satisfactory for this purpose.
6.9 Microscope Lamp, 6 V, 5 A high intensity.
6.10 Stage Micrometer, standard 0.01-0.01 to 0.1-mm0.1 mm scale.
6.11 Ocular Micrometer Scale, 5-mm5 mm linear scale with 100 divisions.
6.12 Standard Counting Specimens.
7. Sampling Requirements
7.1 The sample shall be collected by drawing air filtered to 5 μm through the test garment, impinging the garment-borne
particles on the membrane filter. The filter surface mounted in the open-type aerosol filter holder shall be placed on the outer
surface of the test garment. The garment is firmly clamped to the filter holder by means of the air-filter adapter. During sampling,
the garment shall be hung or carefully positioned to minimize extraneous contamination.
7.2 The standard sample of this test method is secured with the passage of 14 L [0.5 ft ] of air through the test fabric during
a 1-min1 min period at each of five sampling areas as shown in Fig. 3. One sampling area is adequate for caps, helmets, towels,
wipers, and booties with plastic soles. Two areas are suggested for all-fabric booties.
7.3 Locations are approximate and may be modified to suit a specific design factor by agreement.
8. Preparation of Apparatus
8.1 Before sampling when using only a microscope, remove dirt and dust from the filter holder by washing in a free-rinsing
detergent, ketone-free, isopropyl alcohol and submicrometer-filtered reagent grade petroleum ether (boiling range from 30 to
60°C).60 °C).
8.2 Maintain the laboratory equipment and area used for counting and sizing the particles in a condition of cleanliness parallel
or superior to the area sampled. Good clean room and contamination control practices should be followed. Plastic microscope
hoods have proven satisfactory as covering, in a clean room, in the absence of a laboratory clean hood.
8.3 Personnel performing sizing and counting operations shall wear garments and behave in a manner appropriate to the
cleanliness conditions in which they are working.
8.4 Clean and prepare the microscope slides and petri dishes for preserving the membrane filter and specimen. Lens tissue
properly used is satisfactory for this operation.
8.5 Handle hazardous chemicals used in the test method with recognized precautions.
F51/F51M − 20
FIG. 3 Clean Room Garment Sampling Locations
8.6 Establish a background count on membrane filters by examining each filter used for referee purposes. Examination at 40
to 50× magnifications through the microscope will reveal low or high background count.
8.7 Make a background count (Note 2) following the microscopic methods outlined in this test method, upon any filter with a
contamination level approximating 10 % or greater of the estimated test sample (Note 3). This count will be subtracted from the
total count (P ) obtained in 10.1 for each size range.
t
8.8 Place acceptable filters in clean petri dishes and cover. Identify the dishes for test use.
8.9 When using an automated image analyzer, preparation is similar to the preceding except that the white, ungridded
0.08-μm0.08 μm filter is used.
NOTE 2—For routine work, a background count on two filters per box of 100 is adequate under present rigid production methods.
3 3
NOTE 3—If the background count is estimated to be greater than 10 % of the total count from a 0.3-m0.3 m [10-ft [10 ft ] specimen, a larger sample
3 3
0.4-0.4 or 0.6-m0.6 m [15- [15 to 20-ft20 ft ] volume may be used to eliminate background count procedure.
9. Sampling
9.1 With the aid of laboratory pressure tubing, connect the filter holder to a source of vacuum which has been found adequate
to produce a flow rate of 14 L/min [0.5 cfm], at vacuum conditions test (pressure of 5 kPa or 350 torr). The holder may be open,
may contain a limiting orifice (Fig. 4), or may be connected to the flowmeter. If a flowmeter is used between the filter holder and
vacuum source, correction to the standard temperature and pressure must be made to determine actual standard temperature and
pressure flow.
9.2 With clean forceps, carefully remove the appropriate membrane filter from the container and place, with grid side up, when
appropriate, on the screen support of the filter holder (Fig. 5). Twist the locking ring in place after placing the tapered adapter in
position. Similarly, place the 5.0-μm5.0 μm air filter in the top portion of the adapter by removing the O-ring from the adapter top,
placing a 47-mm47 mm white filter on the support screen and replacing the O-ring. (This filter may be used for many tests.)
9.3 See IEST-RP-CC003.2 for additional recommendations on the sampling of garments.
9.4 When ready to sample, place the outer surface of the test garment over the tapered (male) adapter. Firmly lock into test
position by placing the air-filter tapered (female) adapter over the test portion of fabric.
F51/F51M − 20
FIG. 4 Inserting a Typical Orifice
FIG. 5 Placing the Filter on a Typical Screen Support
9.5 Apply vacuum at the predetermined flow rate of 14 L/min [0.5 cfm] for a period of 1 min for each area. Sample required
areas (Fig. 3) by repeating 9.2.
9.6 Remove the filter from the holder with forceps and place it between the clean microscope slides, in a clean transport
container (see 6.4.4) or in a clean petri dish for transport to the microscope counting area. The membrane must be cleaned before
placing it in the transport container.
10. Microscope Analysis Procedure
10.1 Place the ocular micrometer in one eyepiece. Using a stage micrometer, calibrate the measuring eyepiece (ocular
micrometer) for each magnification (Fig. 6). A whipple disk similarly calibrated is
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