ASTM D6057-96(2001)e1

Standard Test Method for Determining Concentration of Airborne Single-Crystal Ceramic Whiskers in the Workplace Environment by Phase Contrast Microscopy

SCOPE
1.1 This test method covers the sampling methods and analysis techniques used to assess the airborne concentration of single-crystal ceramic whiskers (SCCW), such as silicon carbide and silicon nitride, which may occur in and around the workplace where these materials are manufactured, processed, transported, or used. This test method is based on the collection of fibers by filtration of a known quantity of air through a filter. The filter is subsequently evaluated with a phase contrast microscope (PCM) for the number of fibers meeting appropriately selected counting criteria. This test method cannot distinguish among different types of fibers. This test method may be appropriate for other man-made mineral fibers (MMMF).
1.2 This test method is applicable to the quantitation of fibers on a collection filter that are greater than 5 μm in length, less than 3 μm in width, an have an aspect ratio equal to or greater than 5:1. The data are directly convertible to a statement of concentration per unit volume of air sampled. This test method is limited by the diameter of the fibers visible by PCM (typically greater than 0.25 um in width) and the amount and type of coincident interference particles.  
1.3 A more definitive analysis may be necessary to confirm the identity and dimensions of the fibers located with the PCM, especially where other fiber types may be present. Such techniques may include scanning electron microscopy (SEM) or transmission electron microscopy (TEM). The use of these test methods for the identification and size determination of SCCW is described in Practice D 6058 and Test Methods D 6059 and D 6056.  
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Dec-1996
• ICS: 13.040.30 - Workplace atmospheres
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.04 - Workplace Air Quality

Relations

• Replaces: ASTM D6057-96 - Standard Test Method for Determining Concentration of Airborne Single-Crystal Ceramic Whiskers in the Workplace Environment by Phase Contrast Microscopy
• Effective Date: 10-Dec-1996
• Replaced By: ASTM D6057-96(2006) - Standard Test Method for Determining Concentration of Airborne Single-Crystal Ceramic Whiskers in the Workplace Environment by Phase Contrast Microscopy
• Effective Date: 01-Oct-2006
• Referred By: ASTM D6058-96(2016) - Standard Practice for Determining Concentration of Airborne Single-Crystal Ceramic Whiskers in the Workplace Environment
• Effective Date: 10-Dec-1996

Standards Content (Sample)

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
e1
Designation:D6057–96 (Reapproved 2001)
Standard Test Method for
Determining Concentration of Airborne Single-Crystal
Ceramic Whiskers in the Workplace Environment by Phase
Contrast Microscopy
This standard is issued under the fixed designation D6057; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Apparatus supplier name in Footnote 6 was deleted editorially in November 2001.
1. Scope 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the sampling methods and
responsibility of the user of this standard to establish appro-
analysistechniquesusedtoassesstheairborneconcentrationof
priate safety and health practices and determine the applica-
single-crystal ceramic whiskers (SCCW), such as silicon car-
bility of regulatory limitations prior to use.
bide and silicon nitride, which may occur in and around the
workplace where these materials are manufactured, processed,
2. Referenced Documents
transported,orused.Thistestmethodisbasedonthecollection
2.1 ASTM Standards:
offibersbyfiltrationofaknownquantityofairthroughafilter.
D1193 Specification for Reagent Water
The filter is subsequently evaluated with a phase contrast
D1356 Terminology Relating to Sampling andAnalysis of
microscope (PCM) for the number of fibers meeting appropri-
Atmospheres
ately selected counting criteria. This test method cannot
D4532 Test Method for Respirable Dust in Workplace
distinguish among different types of fibers. This test method
Atmospheres
may be appropriate for other man-made mineral fibers
D6056 Test Method for Determining Concentration of
(MMMF).
Airborne Single-Crystal Ceramic Whiskers in the Work-
1.2 This test method is applicable to the quantitation of
place Environment by Transmission Electron Microscopy
fibers on a collection filter that are greater than 5 µm in length,
D6058 PracticeforDeterminingConcentrationofAirborne
less than 3 µm in width, and have an aspect ratio equal to or
Single-Crystal Ceramic Whiskers in the Workplace Envi-
greater than 5:1. The data are directly convertible to a
ronment
statementofconcentrationperunitvolumeofairsampled.This
D6059 Test Method for Determining Concentration of
test method is limited by the diameter of the fibers visible by
Airborne Single-Crystal Ceramic Whiskers in the Work-
PCM (typically greater than 0.25 µm in width) and the amount
place Environment by Scanning Electron Microscopy
and type of coincident interference particles.
E691 Practice for Conducting Interlaboratory Study to
1.3 Amore definitive analysis may be necessary to confirm
Determine the Precision of a Test Method
theidentityanddimensionsofthefiberslocatedwiththePCM,
especially where other fiber types may be present. Such
3. Terminology
techniques may include scanning electron microscopy (SEM)
3.1 Definitions:
or transmission electron microscopy (TEM). The use of these
3.1.1 analytical sensitivity, n—airborne fiber concentration
test methods for the identification and size determination of
represented by a single fiber counted in the PCM.
SCCW is described in Practice D6058 and Test Methods
3.1.1.1 Discussion—Although the terms fiber and whisker
D6059 and D6056.
are, for convenience, used interchangeably in this test method,
1.4 The values stated in SI units are to be regarded as the
whisker is correctly applied only to single-crystal fibers
standard. The values given in parentheses are for information
whereas a fiber may be single- or poly-crystalline or may be
only.
noncrystalline.
1 2
This test method is under the jurisdiction of ASTM Committee D22 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Sampling andAnalysis and is the direct responsibility of Subcommittee D22.04 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Analysis of Workplace Atmospheres. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved December 10, 1996. Published February 1997. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
D6057–96 (2001)
3.1.2 aspect ratio, n—the ratio of the length of a fiber to its method does not differentiate based on chemistry or morphol-
width. ogy, all fibers in accordance with the definitions in Section 3
3.1.3 fiber, n—for the purpose of this test method,an shall be counted.
elongated particle having a length greater than 5 µm, a width 6.1.1 This test method has been designed to filter air for the
less than 3 µm, and an aspect ratio equal to or greater than 5:1. determination of fiber concentration. However, filtration of air
3.1.4 man-made mineral fiber, n—any inorganic fibrous also involves collection of extraneous particles. Extraneous
material produced by chemical or physical processes. particles may obscure fibers by overlay or by discoloration of
3.1.5 single-crystal ceramic whisker, n— a man-made min- the filter. This situation can be managed by regulating the air
eral fiber that has a single-crystal structure. volume sampled and thus the filter loading. Fibers should
3.2 For definitions of other terms used in this test method, appear separated from other particles to ensure an adequate
see Terminology D1356. opportunity for their recognition as separate entities in the
PCM and accurate counting. Some coincident particulate
4. Summary of Test Method
agglomeration does occur even with these guidelines.Analyze
an alternate filter with a reduced loading if the obscuring
4.1 The sample is collected on a mixed cellulose ester
condition appears to exceed 15% of the filter area (5).
(MCE) filter by drawing air, using a sampling pump, through
Redeposition of a portion of an overloaded filter is permitted
an open-face 25-mm electrically conductive sampling cassette
only in circumstances where an alternate filter is not available
assembly (1,2). Asectionoftheopaquefilterisconvertedinto
and cannot be obtained through resampling (see 10.1.9).
an optically transparent homogeneous specimen using an
acetone vaporizer. The fibers are counted by PCM at a
7. Apparatus and Reagents
magnification of approximately 4003 using the criteria dis-
cussed in Section 11. Results are expressed as a fiber concen-
7.1 Sampling Cassette—Use a 25-mm, electrically conduc-
tration per unit volume of air and a fiber loading per unit area
tive cassette assembly such as a three-piece cassette with an
of filter. The airborne concentration is expressed as fibers per
extension cowl or retainer ring, or both, containing a 0.45-µm
millilitre(f/mL)andthefiberloadingisexpressedasfibersper
pore size MCE filter and a support pad. Seal the cassette
square millimetre (f/mm ).
assembly with shrink tape. Reloading of used cassettes is not
permitted.
5. Significance and Use
7.2 Personal Sampling Pump—Use a portable battery-
5.1 TheSCCWmaybepresentintheworkplaceatmosphere
operated pump for personal sampling. Each pump must be
where these materials are manufactured, processed, trans-
capable of operating within the range from 0.5 to 4 L/min and
ported, or used. This test method can be used to monitor
continuously over the chosen sampling period (1). The flow
airborne concentrations of fibers in these environments. It may
mustbefreefrompulsation.Allpumpsshallbecalibratedprior
be employed as part of a personal or area monitoring strategy.
to use (6).
5.2 Thistestmethodisbasedondimensionalconsiderations
7.3 Area Sampling Pump—Use a personal sampling pump
only.Assuch,itdoesnotprovideapositiveidentificationofthe
or a non-portable high-volume pump for area sampling. Each
fibers counted. Analysis by SEM or TEM is required when
pump shall be capable of operating within the range from 0.5
additional fiber identification information is needed.
to 16 L/min and continuously over the chosen sampling period
(1). The flow shall be free from pulsation. All pumps shall be
NOTE 1—This test method assumes that the analyst is familiar with the
calibrated prior to use (6).
operation of PCM instrumentation and the interpretation of data obtained
7.4 Vinyl Tubing, or equivalent.
using this technique.
7.5 Microscope—Positive phase contrast light, with green
5.3 This test method is not appropriate for measurement of
orbluefilter,8to103eyepiece,and40to453phaseobjective
fibers with diameters less than approximately 0.25 µm due to
(total magnification approximately 4003); numerical aper-
visibility limitations associated with PCM. The SEM or TEM
ture=0.65 to 0.75.
methods may be used to provide additional size information of
7.6 Acetone Vaporizer—A device used to clear the MCE
SCCW if needed (refer to Practice D6058 for additional
filter by exposure to a small amount of vaporized acetone.
information on the use of these methods).
7.7 Graticule, with standardized 100-µm diameter circular
5.4 Resultsfromtheuseofthistestmethodshallbereported
−3
field at the specimen plane (calibrated area ' 7.8 310
along with 95% confidence limits for the samples being
mm ), with the capability to compare diameters and lengths at
studied. Individual laboratories shall determine their intralabo-
3 and 5 µm, respectively, within the field of view.
ratory coefficient of variation and use it for reporting 95%
confidence limits (1,3,4).
NOTE 2—The graticule is custom-made for each microscope. Specify
disk diameter needed to exactly fit the ocular of the microscope and the
6. Interferences diameter (millimetres) of the circular counting area (see section 12.2.1).
TheWalton-BeckettTypeG-24graticuleorotherequivalentgraticulesare
6.1 All fibers meeting the dimensional criteria in Section 3
recommended. Graticules designed for the NIOSH 7400Arules, such as
are not necessarily of the same composition. Since the PCM
the Walton-Beckett Type G-22, are not recommended.
NOTE 3—In some microscopes, adjustments of the interocular distance
will change the tube length and hence magnification of the microscope.
Each analyst shall separately measure the diameter of his or her field of
The boldface numbers in parentheses refer to a list of references at the end of
this test method. view and this value shall be used in all calculations.
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D6057–96 (2001)
7.8 Phase Shift Test Slide equivalent to HSE/NPL. ~A ! ~F !
c L
t 5 (1)
7.9 Telescope, (ocular phase-ring centering) or Bertrand ~Q! ~C !10
e
lens.
where:
7.10 Stage Micrometer, (0.01-mm divisions).
A = active filter collection area (;385 mm for 25-mm
c
7.11 Tweezers.
filter),
7.12 Scalpel Blades.
t = time, min,
7.13 MCE Filters, 25 mm, 0.45 µm and 0.22 µm.
F = fiber loading, f/mm ,
L
7.14 Funnel/Filter Assembly,25mm.
Q = sampling flow rate, L/min,
7.15 Triacetin (glycerol triacetate).
C = estimated concentration of SCCW, f/mL, and
e
7.16 Acetone.
10 = conversion factor.
NOTE 4—Precaution:Acetone is a flammable liquid and requires 2
NOTE 5—While the desired minimum loading is 100 f/mm , the
precaution not to ignite it accidentally. 2
minimum loading that has statistical significance is 7 f/mm after blank
correction (1).
7.17 ASTM D1193 Type II Water (particle free).
NOTE 6—Experience has shown that the fiber loading should not
7.18 Purity of Reagents—Reagent grade chemicals shall be
exceed1300f/mm (12fibers/graticulearea,averagevalueforallcounted
used in all tests. Unless otherwise indicated, it is intended that
fields) for the majority of sampling situations (1).
all reagents conform to the specifications of the Committee on
8.5.4 At a minimum, check the flow rate before and after
Analytical Reagents of theAmerican Chemical Society where
sampling. If the difference is greater than 10% from the initial
such specifications are available. Other grades may be used,
flow rate, the sample shall be rejected. Also see Test Method
provided it is first ascertained that the reagent is of sufficiently
D4532.
high purity to permit its use without lessening the accuracy of
8.6 Carefullyremovethecassettefromthetubingattheend
the determination.
of the sampling period (ensure that the cassette is positioned
upright before interrupting the pump flow). Replace the inlet
8. Sample Collection
cap and inlet and outlet plugs, and store the cassette.
8.1 CollectsamplesofairborneSCCWonMCEfiltersusing
sampling cassettes and pumps in accordance with Section 7.
NOTE 7—Deactivate the sampling pump prior to disconnecting the
8.2 Remove the outlet plug from the sampling cassette and cassette from the tubing.
connect it to a sampling pump by means of flexible,
8.7 Submit at least one field blank (or a number equal to
constriction-proof tubing.
10% of the total samples, whichever is greater) for each set of
8.3 Perform a leak check of the sampling system by
samples. Remove the cap of the field blank briefly (approxi-
activating the pump with the closed cassette and rotameter (or
mately 30 s) at the sampling site, then replace it. The field
other flow measurement device) in line. Any flow indicates a
blank is used to monitor field sampling procedures. Field
leak that must be eliminated before starting the sampling
blanks shall be representative of filters used in sample collec-
operation.
tion (for example, same filter lot number).
8.4 Remove the inlet plug from the sampling cassette to
8.8 Submit at least one unused and unopened sealed blank
eliminate any vacuum that may have accumulated during the
which is used to monitor the supplies purchased as well as
leak test; then remove the entire inlet cap.
procedures used in the laboratory. The sealed blank shall be
8.5 Conduct personal and area sampling as follows:
representativeoffiltersusedinsamplecollection(forexample,
8.5.1 For personal sampling, fasten the sampling cassette to
same filter lot number).
the worker’s lapel in the worker’s breathing zone and orient it
9. Transport of Samples
face down. Adjust the calibrated flow rate to a value between
0.5and4L/min (1).Typically,asamplingratebetween0.5and
9.1 Ship the samples in a rigid container with sufficient
2.5 L/min is selected (2-5,7). Also see Test Method D4532.
packing material to prevent jostling or damage. Care shall be
8.5.2 Placeareasamplesonanextensionrodfacingdownat
taken to minimize vibrations and cassette movement.
a 45° angle.Adjust the calibrated flow rate to a value between
NOTE 8—Do not use shipping material that may develop electrostatic
0.5and16L/min (1).Typically,asamplingratebetween1and
forces or generate dust.
10 L/min is selected (8).
NOTE 9—Shipping containers for 25-mm sampling cassettes are com-
8.5.3 Set the sampling flow rate and time t
...