ASTM F51-00(2002)e1
(Test Method)Standard Test Method for Sizing and Counting Particulate Contaminant In and On Clean Room Garments
Standard Test Method for Sizing and Counting Particulate Contaminant In and On Clean Room Garments
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® or Gortex®. It only applies to fabrics that are porous such as cotton or polyester.
1.3 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are for information only.
1.4 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.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: F 51 – 00 (Reapproved 2002)
Standard Test Method for
Sizing and Counting Particulate Contaminant In and On
Clean Room Garments
ThisstandardisissuedunderthefixeddesignationF 51;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Section 7.1 was revised editorially in October 2002.
1. Scope 2.2 Institute of Environmental Sciences and Technology
(IEST) Document:
1.1 This test method covers the determination of detachable
IEST-RP-CC003.2, Garment System Considerations for
particulate contaminant 5 µm or larger, in and on the fabric of
Cleanrooms and Other Controlled Environments
clean room garments.
1.2 This test method does not apply to nonporous fabrics
3. Terminology
such as Tyvekt or Gortext. It only applies to fabrics that are
3.1 Definitions:
porous such as cotton or polyester.
3.1.1 fiber, n—particle longer than 100 µm and with a
1.3 The values stated in SI units are to be regarded as the
length-to-width ratio exceeding 10:1.
standard. The inch-pound values given in parentheses are for
-6
3.1.2 micrometre (µm), n—SI unit of length which is 10 of
information only.
a metre or approximately 0.000 04 in.
1.4 Thistestmethodprovidesnotonlythetraditionaloptical
3.1.3 particle size (L) (µm)—major projected dimension of
microscopic analysis but also a size distribution and surface
a particle.
obscuration analysis for particles on a fine-textured membrane
filter or in a tape lift sample. It utilizes transmitted illumination
4. Summary of Test Method
torenderallparticlesdarkerthanthebackgroundforgraylevel
4.1 Filtered air is drawn through five designated 0.01-m
detection. Particles collected on opaque plates must be trans-
2 2
(1.5-in. or approximately 0.01-ft ) areas of a single thickness
ferred to a suitable membrane filter.
of the garment fabric at a rate of 14 L/min (0.5 cfm) for a
1.5 This standard may involve hazardous materials, opera-
period of 1 min for each area.
tions, and equipment. This standard does not purport to
4.2 The air drawn through the garment subsequently passes
address all of the safety concerns, if any, associated with its
through a membrane filter disk, impinging the entrained
use. It is the responsibility of the user of this standard to
particles upon the filter surface.
establish appropriate safety and health practices and deter-
4.3 The filter disk is then examined microscopically for
mine the applicability of regulatory limitations prior to use.
particles removed from the garment.
4.4 For particles larger than 5 µm, use optical analysis. For
2. Referenced Documents
particles smaller than 5 µm, use automated image analysis.
2.1 ASTM Standards:
4.5 Cleaning and counting techniques are in accordance
E 1216 Practice for Sampling for Surface Particulate Con-
2 with those established in Section 10.
tamination by Tape Lift
F 25 Test Method for Sizing and Counting Airborne Par-
5. Significance and Use
ticulate Contamination in Clean Rooms and Other Dust-
5.1 The test method for particulate sizing and numbers on
Controlled Areas Designed for Electronic and Similar
2 garments is nondestructive and may be used to evaluate the
Applications
contamination levels of fibers and particles on and in clean
room garments. The test may be used for evaluating the
This test method is under the jurisdiction of ASTM Committee E21 on Space cleanliness levels of new or newly cleaned garments. It also
Simulation andApplications of Space Technology and is the direct responsibility of
may be used to evaluate the extent of fiber and particulate
Subcommittee E21.05 on Contamination.
Current edition approved May 10, 2000. Published July 2000. Originally
published as F 51 – 65. Discontinued in August 1998 and reinstated as F 51 – 00.
2 3
Annual Book of ASTM Standards, Vol 15.03. Available from IEST, 940 E. Northwest Highway, Mount Prospect, IL 60056.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F 51 – 00 (2002)
FIG. 1 Filter Assembly
FIG. 2 Adapter
contamination on garments that have been worn, if necessary.
6.4.4 Plastic Petri Slides with Covers , plastic petri dishes,
For this application, it is necessary to sample representative
60-mm diameter or glass microscope slides, 50 by 75 mm.
areas of the garment fabric.
6.5 Binocular Microscope, withocular-objectivecombina-
tions to obtain 40 to 453 and 90 to 1503 magnifications.
6. Apparatus
Latter objective shall have a numerical aperture of 0.15 min.
6.1 Filter Assembly and Adapter , see Fig. 1and Fig. 2.
Fig. 3shows suitable apparatus.
6.1.1 Filter Holder, aerosol open type having an effective
6.6 Programmable Image Analyzer, a Computer-Driven Mi-
filter area of 960 6 25 mm .
croscope Which Counts and Sizes Particles With Automated
6.2 Vacuum Pump or Aspirator, capable of operating at a
Stage and Automated Focus Interface:
pressure of 7 kPa (500 torr) with a flow rate of 14 L/min (0.5
6.6.1 Microscope, with a large glass platform automatic
cfm).
stage and automated focus.
6.3 Flowmeter or Orifice , calibrated and having a capacity
6.6.2 Objectives and Projection Lenses, to generate a pixel
in excess of 14 L/min (0.5 cfm), or a limiting orifice calibrated
dimension of about 5 µm or less.
with the pump, filter holder, and filter used for this test method
6.7 Forceps, with unserrated tips.
at a flow rate of 14 6 0.5 L/min (0.50 6 0.02 cfm). Ensure, 8
6.8 Normal Counter , (2 gang) or equivalent.
visually, that the orifice is free of obstructing matter before 9
6.9 Microscope Lamp , 6 V, 5 A high intensity.
each test. 10
6.10 Stage Micrometer , standard 0.01- to 0.1-mm scale.
4,5
6.4 Membrane Filters : 11
6.11 Ocular Micrometer Scale , 5-mm linear scale with
6.4.1 Black, 0.80-µm pore size, 47-mm diameter with
100 divisions.
3.08-mm imprinted grid for fabric particles. 4
6.12 Standard Counting Specimens .
6.4.2 White, 0.80-µm pore size, 47-mm diameter without
imprinted grid for fabric particles and automated image ana-
7. Sampling Requirements
lyzer.
7.1 The sample shall be collected by drawing air filtered to
6.4.3 White, 5.0-µm pore size, 47-mm diameter (air prefilter
5 µm through the test garment, impinging the garment-borne
used with the filters in 6.4.1 and 6.4.2).
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 following equipment is satisfactory for this test method except where
mentionedotherwise.Thefollowingpartnumbersrefertoequipmentavailablefrom
Millipore Filter Corp.: Analyslides,GelmanSciences,AnnArbor,MI,havebeenfoundsatisfactoryfor
(1) Fabric Particle MonitoringAssembly, #XX50 047 40, Millipore Filter Corp., use with microscopes.
Bedford,MA01730,Gelman1200Awith1207AdapteravailablefromGelmanCo., Microscopes such as Bausch & Lomb No. TBV-5, Series C,American Optical
Chelsea, MI or equivalent. Co. X2BUHBW, Leitz SM 0.4.4S 25/81; and Zeiss Model KF 124-212 (with
(2) Adapter No. XX50 047 45, or equivalent. accessories), or equivalent, have been found satisfactory for this purpose.
(3) Limiting Orifice XX50 000 00. The Veeder Root counter has been found satisfactory for this purpose.
(4) Forceps with unserrated tips. The AO Spencer, or equivalent lamp, has been found satisfactory for this
(5) Check Slide Photographic, XX 50 000 50 or equivalent. purpose.
(6) Aerosol Monitors Type M A BG037A0. Bausch&LombNo.31-16-00,orequivalentscale,hasbeenfoundsatisfactory
(7) Adapter, XX 62 000 04. for this purpose.
5 11
Filters manufactured by the Millipore Filter Corp., Bedford, MA 01730 or Bausch & Lomb No. 31-16-99, or equivalent micrometer, has been found
Gelman Co., Chelsea, MI, have been found satisfactory for this purpose. satisfactory for this purpose.
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F 51 – 00 (2002)
FIG. 3 Typical Air-Sampling Filtration Apparatus
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
FIG. 4 Typical Counting and Sizing Microscope and Illuminator
thepassageof14L(0.5ft )ofairthroughthetestfabricduring (see Test Method F 25)
a 1-min period at each of five sampling areas as shown in Fig.
4. One sampling area is adequate for caps, helmets, towels,
wipers, and booties with plastic soles. Two areas are suggested
8.8 Place acceptable filters in clean petri dishes and cover.
for all-fabric booties.
Identify the dishes for test use.
7.3 Locations are approximate and may be modified to suit
8.9 Whenusinganautomatedimageanalyzer,preparationis
a specific design factor by agreement.
similar to the preceding except that the white, ungridded
0.08-µm filter is used.
8. Preparation of Apparatus
NOTE 1—For routine work, a background count on two filters per box
8.1 Before sampling when using only a microscope, remove
of 100 is adequate under present rigid production methods.
dirt and dust from the filter holder by washing in a free-rinsing
NOTE 2—If the background count is estimated to be greater than 10 %
3 3
detergent, ketone-free, isopropyl alcohol and submicrometer-
of the total count from a 0.3-m (10-ft ) specimen, a larger sample 0.4- or
3 3
filteredreagentgradepetroleumether(boilingrangefrom30to
0.6-m (15- to 20-ft ) volume may be used to eliminate background count
procedure.
60°C).
8.2 Maintain the laboratory equipment and area used for
9. Sampling
counting and sizing the particles in a condition of cleanliness
parallel or superior to the area sampled. Good clean room and 9.1 With the aid of laboratory pressure tubing, connect the
contamination control practices should be followed. Plastic filter holder to a source of vacuum which has been found
microscope hoods have proven satisfactory as covering, in a adequate to produce a flow rate of 14 L/min (0.5 cfm), at
clean room, in the absence of a laboratory clean hood. vacuum conditions test (pressure of 5 kPa or 350 torr). The
8.3 Personnel performing sizing and counting operations holder may be open, may contain a limiting orifice (Fig. 5), or
shall wear garments and behave in a manner appropriate to the may be connected to the flowmeter. If a flowmeter is used
cleanliness conditions in which they are working. between the filter holder and vacuum source, correction to the
8.4 Cleanandpreparethemicroscopeslidesandpetridishes standard temperature and pressure must be made to determine
for preserving the membrane filter and specimen. Lens tissue actual standard temperature and pressure flow.
properly used is satisfactory for this operation. 9.2 With clean forceps, carefully remove the appropriate
8.5 Handle hazardous chemicals used in the test method membrane filter from the container and place, with grid side
with recognized precautions. up, when appropriate, on the screen support of the filter holder.
8.6 Establish a background count on membrane filters by Twistthelockingringinplaceafterplacingthetaperedadapter
examiningeachfilterusedforrefereepurposes.Examinationat in position (Fig. 6). Similarly, place the 5.0-µm air filter in the
40 to 503 magnifications through the microscope will reveal top portion of the adapter by removing the O-ring from the
low or high background count. adapter top, placing a 47-mm white filter on the support screen
8.7 Make a background count (Note 1) following the and replacing the O-ring. (This filter may be used for many
microscopic methods outlined in this test method, upon any tests.)
filterwithacontaminationlevelapproximating10 %orgreater 9.3 See IEST-RP-CC003.3 for additional recommendations
of the estimated test sample (Note 2). This count will be on the sampling of garments.
subtracted from the total count (P) obtained in 10.1 for each 9.4 Whenreadytosample,placetheoutersurfaceofthetest
t
size range. garment over the tapered (male) adapter. Firmly lock into test
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F 51 – 00 (2002)
slide lightly with silicone stopcock lubricant before mounting
the filter will assist in holding the filter flat in place.
10.4 Adjust the external light source to obtain maximum
particle definition with an illumination angle of approximately
45°. High-intensity illumination is a critical requirement.
10.5 Use a magnification of approximately 453 for count-
ing particles 50 µm or larger and approximately 1003 for
particles smaller than 50 µm. Greater magnifications may be
advantageous for examination to identify particles.
NOTE 4—Analysis for particles in the 0.5- to 5.0-µm size range may be
achieved by using transmitted light techniques, after rendering the white
filter transparent by placing the filter on immersion oil of refractive index
1.515. A magnification of at least 5003 is required. For transmitted light
microscopy, a white filter must be used (instead of black filter) since only
FIG. 5 Inserting a Typical Orifice
the white filter can be rendered transparent with immersion oil. If a
smaller pore size filter is used, the flowmeter used and the limiting orifice
will require calibration with the filter holder and filter in place.
10.6 Particles should be counted and tabulated in two size
ranges: particles greater than 50 µm and particles 5 to 50 µm.
Particlessmallerthan5µmarenottobecountedbythemanual
counting method. The size of particles is determined by its
greater projected dimension. Fibers are counted as particles
and are counted separately as fibers.
10.7 Test Method of Counting Particles:
10.7.1 Adjust the microscope focus and lamp position so
thatthemaximumclarityoffiltersurfaceandparticledefinition
is obtained.
10.7.2 With the lower magnification (approximately 453),
count the particles in a number of grid squares selected at
FIG. 6 Placing the Filter on a Typical Screen Support
random until meeting the statistical requirements in 10.9.
10.7.2.1 For particles larger than 50 µm, use the manual
position by placing the air-filter tapered (female) adapter over counter (6.8).
the test portion of fabric.
10.7.3 At the higher magnification (1003), count the num-
9.5 Apply vacuum at the predetermined flow rate of 14
ber of particles in the 5- to 50-µm range in a number of grid
L/min (0.5 cfm) for a period of 1 min for each area. Sample
squares selected at random until meeting the statistical require-
required areas (Fig. 3) by repeating 9.3.
ments in 10.9. Use the manual counter (6.8).
9.6 Removethefilterfromtheholderwithforcepsandplace
10.7.4 If the total number of particles in this range is
it between the
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