ASTM D6056-96(2011)
(Test Method)Standard Test Method for Determining Concentration of Airborne Single-Crystal Ceramic Whiskers in the Workplace Environment by Transmission Electron Microscopy (Withdrawn 2020)
Standard Test Method for Determining Concentration of Airborne Single-Crystal Ceramic Whiskers in the Workplace Environment by Transmission Electron Microscopy (Withdrawn 2020)
SIGNIFICANCE AND USE
The SCCW may be present in the workplace atmosphere where these materials are manufactured, processed, transported, or used. This test method can be used to monitor airborne concentrations of fibers in these environments. It may be employed as part of a personal or area monitoring strategy.
This test method is based on morphology, elemental composition, and crystal structure. The analysis technique has the ability to positively identify SCCW.
Note 1—This test method assumes that the analyst is familiar with the operation of TEM/EDS instrumentation and the interpretation of data obtained using these techniques.
This test method is applicable for the measurement of the total population of SCCW fibers including fibers with diameters ≤0.1 μm.
Results from the use of this test method shall be reported along with 95 % confidence limits for the samples being studied. Individual laboratories shall determine their intralaboratory coefficient of variation and use it for reporting 95 % confidence limits (2,5,6).
SCOPE
1.1 This test method covers the sampling methods and analysis techniques used to assess the airborne concentration and size distribution 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 filtration of a known quantity of air through a filter. The filter is subsequently evaluated with a transmission electron microscope (TEM) for the number of fibers meeting appropriately selected morphological and compositional criteria. This test method has the ability to distinguish among different types of fibers based on energy dispersive X-ray spectroscopy (EDS) analysis and selected area electron diffraction (SAED) analysis. 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 0.5 μm in length, less than 3 μm in width, and have an aspect ratio equal to or greater than 5:1 (1). The data are directly convertible to a statement of concentration per unit volume of air sampled. This test method is limited by the amount of coincident interference particles.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
WITHDRAWN RATIONALE
This test method covers the sampling methods and analysis techniques used to assess the airborne concentration and size distribution 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.
Formerly under the jurisdiction of Committee D22 on Air Quality, this test method was withdrawn in January 2020 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
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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
Designation: D6056 − 96 (Reapproved 2011)
Standard Test Method for
Determining Concentration of Airborne Single-Crystal
Ceramic Whiskers in the Workplace Environment by
Transmission Electron Microscopy
This standard is issued under the fixed designation D6056; 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 1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This test method covers the sampling methods and
ization established in the Decision on Principles for the
analysis techniques used to assess the airborne concentration
Development of International Standards, Guides and Recom-
and size distribution of single-crystal ceramic whiskers
mendations issued by the World Trade Organization Technical
(SCCW),suchassiliconcarbideandsiliconnitride,whichmay
Barriers to Trade (TBT) Committee.
occur in and around the workplace where these materials are
manufactured, processed, transported, or used. This test
2. Referenced Documents
method is based on the filtration of a known quantity of air
2.1 ASTM Standards:
through a filter. The filter is subsequently evaluated with a
D1193Specification for Reagent Water
transmission electron microscope (TEM) for the number of
D1356Terminology Relating to Sampling and Analysis of
fibers meeting appropriately selected morphological and com-
Atmospheres
positional criteria. This test method has the ability to distin-
D4532Test Method for Respirable Dust in Workplace At-
guish among different types of fibers based on energy disper-
mospheres Using Cyclone Samplers
sive X-ray spectroscopy (EDS) analysis and selected area
D6057Test Method for Determining Concentration of Air-
electron diffraction (SAED) analysis.This test method may be
borne Single-Crystal Ceramic Whiskers in the Workplace
appropriate for other man-made mineral fibers (MMMF).
Environment by Phase Contrast Microscopy
1.2 This test method is applicable to the quantitation of D6058Practice for Determining Concentration of Airborne
fibers on a collection filter that are greater than 0.5 µm in
Single-Crystal Ceramic Whiskers in the Workplace Envi-
length, less than 3 µm in width, and have an aspect ratio equal ronment
to or greater than 5:1 (1). The data are directly convertible to
D6059Test Method for Determining Concentration of Air-
a statement of concentration per unit volume of air sampled. borne Single-Crystal Ceramic Whiskers in the Workplace
This test method is limited by the amount of coincident
Environment by Scanning Electron Microscopy
interference particles.
E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.3 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
3. Terminology
only.
3.1 Definitions:
1.4 This standard does not purport to address all of the
3.1.1 analytical sensitivity, n—airborne fiber concentration
safety concerns, if any, associated with its use. It is the
represented by a single fiber counted in the TEM.
responsibility of the user of this standard to establish appro-
3.1.1.1 Discussion—Although the terms fiber and whisker
priate safety, health, and environmental practices and deter-
are, for convenience, used interchangeably in this test method,
mine the applicability of regulatory limitations prior to use.
whiskers is correctly applied only to single-crystal fibers
whereas a fiber may be single- or poly-crystalline or may be
noncrystalline.
This test method is under the jurisdiction of ASTM Committee D22 on Air
3.1.2 aspect ratio, n—the ratio of the length of a fiber to its
Quality and is the direct responsibility of Subcommittee D22.07 on Sampling and
width.
Analysis of Asbestos.
Current edition approved Oct. 1, 2011. Published October 2011. Originally
approved in 1996. Last previous edition approved in 2006 as D6056–96 (2006). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/D6056-96R11. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this test method. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6056 − 96 (2011)
3.1.3 fiber, n—for the purpose of this test method,an air also involves collection of extraneous particles and other
elongatedparticlehavingaminimumlengthof0.5µm,awidth fibers that may not be of interest. Extraneous particles may
lessthan3µm,andanaspectratioequaltoorgreaterthan5:1. obscure fibers by overlay or overloading of the filter. This
situationcanbemanagedbyregulatingtheairvolumesampled
3.1.4 fibrous, adj—composed of parallel, radiating, or inter-
andthusthefilterloading.Fibersshouldappearseparatedfrom
lacedaggregatesoffibers,fromwhichthefibersaresometimes
other particles to ensure an adequate opportunity for their
separable. That is, the crystalline aggregate may be referred to
recognition as separate entities in the TEM and accurate
asfibrousevenifitisnotcomposedofseparablefibers,buthas
counting. Some coincident particulate agglomeration does
that distinct appearance. The term fibrous is used in a general
occur even with these guidelines. Analyze an alternate filter
mineralogical way to describe aggregates.
with a reduced loading if the obscuring condition appears to
3.1.5 man-made mineral fiber, n—any inorganic fibrous
exceed 15% of the filter area (7). Redeposition of a portion of
material produced by chemical or physical processes.
an overloaded filter is permitted only in circumstances where
3.1.6 single-crystal ceramic whisker, n— a man-made min-
an alternate filter is not available and cannot be obtained
eral fiber that has a single-crystal structure.
through resampling (see 10.1.12).
3.2 For definitions of other terms used in this test method,
7. Apparatus and Reagents
see Terminology D1356.
7.1 Sampling Cassette—Use a 25-mm electrically conduc-
4. Summary of Test Method
tive cassette assembly such as a three-piece cassette with an
4.1 The sample is collected on a mixed cellulose ester
extension cowl or retainer ring containing a 0.45-µm pore size
(MCE) filter by drawing air, using a sampling pump, through
MCE filter and a support pad. Seal the cassette assembly with
an open-face 25-mm electrically conductive sampling cassette
shrink tape. Reloading of used cassettes is not permitted.
assembly (2-4). A section of the filter is prepared and trans-
7.2 Personal Sampling Pump—Use a portable battery-
ferred to a TEM grid and the fibers are identified, sized, and
operated pump for personal sampling. Each pump must be
counted at a screen magnification in the range from 8000 to
capable of operating within the range from 0.5 to 4 L/min and
12000× in the TEM in Section 11. Results are reported as a
continuously over the chosen sampling period (2, 3). The flow
fiber concentration per unit volume of air and a fiber loading
mustbefreefrompulsation.Allpumpsshallbecalibratedprior
per unit area of filter. The airborne concentration is expressed
to use (8).
asfiberspermillilitre(f/mL)andthefiberloadingisexpressed
as fibers per square millimetre (f/mm ). Optionally, a supple-
7.3 Area Sampling Pump—Use a personal sampling pump
mentary low-magnification count in the range from 800 to
or a non-portable high-volume pump for area sampling. Each
1200× may also be performed, using the criteria discussed in
pump shall be capable of operating within the range from 0.5
11.1.5, to provide comparison with PCM data.
to16L/minandcontinuouslyoverthechosensamplingperiod
(2, 3).Theflowshallbefreefrompulsation.Allpumpsshallbe
5. Significance and Use
calibrated prior to use (8).
5.1 TheSCCWmaybepresentintheworkplaceatmosphere
7.4 Vinyl tubing or equivalent.
where these materials are manufactured, processed,
7.5 Plasma Asher, a low-temperature asher (LTA) is re-
transported, or used. This test method can be used to monitor
airborne concentrations of fibers in these environments. It may quired to plasma-etch the collapsed MCE filter.
be employed as part of a personal or area monitoring strategy.
7.6 Oxygen, used as a bleed gas for plasma asher.
5.2 This test method is based on morphology, elemental
7.7 Vacuum Evaporator, for vapor deposition of conductive
composition, and crystal structure. The analysis technique has
layers of carbon.
the ability to positively identify SCCW.
NOTE 2—Sputter coaters and carbonaceous fiber coaters are not
NOTE 1—This test method assumes that the analyst is familiar with the
appropriate.
operation of TEM/EDS instrumentation and the interpretation of data
obtained using these techniques.
7.8 Specimen Grids, copper 200-mesh TEM grids for
5.3 This test method is applicable for the measurement of
mounting the specimen for TEM examination.
the total population of SCCW fibers including fibers with
7.9 Transmission Electron Microscope—ATEM capable of
diameters ≤0.1 µm.
operating using an accelerating voltage of at least 80 kV. The
5.4 Resultsfromtheuseofthistestmethodshallbereported
TEM must also be capable of performing EDS and SAED
along with 95% confidence limits for the samples being
analyses. A light-element X-ray analyzer capable of detecting
studied. Individual laboratories shall determine their intralabo-
carbon, nitrogen, and oxygen is recommended. Use of a
ratory coefficient of variation and use it for reporting 95%
tilt-rotation holder as well as a double-tilt stage is also
confidence limits (2,5,6).
recommended. The TEM must have a fluorescent screen
inscribed with calibrated gradations. It must be capable of
6. Interferences
producing a spot less than 250 nm in diameter at crossover
6.1 This test method has been designed to filter air for the under routine analytical conditions. Scanning transmission
determination of SCCW concentration. However, filtration of electronmicroscope(STEM)modeisallowedforthispurpose.
D6056 − 96 (2011)
7.10 Sample Preparation Area, consisting of either a clean 8.5.3 Set the sampling flow rate and time to produce an
room facility or a room containing a positive pressure HEPA- optimumfiberloadingbetween100and1300f/mm (2-4).The
filtered hood. time of sampling can be estimated by using the following
equation:
7.11 Tweezers.
A F
~ ! ~ !
c L
7.12 Scalpel Blades.
t 5 (1)
~Q!~C ! 10
e
7.13 Large Glass Petri Dishes (approximately 90 mm in
where:
diameter).
A = active filter collection area (;385 mm for 25-mm
c
7.14 Jaffe Washer.
filter),
7.15 Lens Tissue.
t = time, min,
F = fiber loading, f/mm ,
7.16 MCE Filters, 25 mm, 0.45 µm, and 0.22 µm. L
Q = sampling flow rate, L/min,
7.17 Funnel/Filtration Assembly, 25 mm.
C = estimated concentration of SCCW, f/mL, and
e
7.18 Acetone. (Warning—Acetone is a flammable liquid 10 = conversion factor.
and requires precautions not to ignite it accidently.)
8.5.4 At a minimum, check the flow rate before and after
7.19 Specification D1193 Type II Water (particle free). sampling. If the difference is greater than 10% from the initial
flow rate, the sample shall be rejected. Also see Test Method
7.20 Purity of Reagents—Reagent grade chemicals shall be
D4532.
used in all tests. Unless otherwise indicated, it is intended that
all reagents conform to the specifications of the Committee on 8.6 Carefullyremovethecassettefromthetubingattheend
Analytical Reagents of theAmerican Chemical Society where of the sampling period (ensure that the cassette is positioned
such specifications are available. Other grades may be used, upright before interrupting the pump flow). Replace the inlet
provided it is first ascertained that the reagent is of sufficiently cap and inlet and outlet plugs, and store the cassette.
high purity to permit its use without lessening the accuracy of
NOTE 3—Deactivate the sampling pump prior to disconnecting the
the determination.
cassette from the tubing.
8.7 Submit at least one field blank (or a number equal to
8. Sample Collection
10% of the total samples, whichever is greater) for each set of
8.1 CollectsamplesofairborneSCCWonMCEfiltersusing
samples. Remove the cap of the field blank briefly (approxi-
sampling cassettes and pumps in accordance with Section 7.
mately 30 s) at the sampling site, then replace it. The field
8.2 Remove the outlet plug from the sampling cassette and blank is used to monitor field sampling procedures. Field
connect to a sampling pump by means of flexible, constriction blanks shall be representative of filters used in sample collec-
proof tubing. tion (for example, same filter lot number).
8.3 Perform a leak check of the sampling system by 8.8 Submit at least one unused and unopened sealed blank
which is used to monitor the supplies purchased as well as
activating the pump with the closed cassette and rotameter (or
other flow measurement device) in line. Any flow indicates a procedures used in the laboratory. The sealed blank shall be
representativeoffiltersusedinsamplecollection(forexample,
leak that must be eliminated before starting the sampling
operation. same filter lot number).
8.4 Remove the inlet plug from the sampling cassette to
9. Transport of Samples
eliminate any vacuum that may have accumulated during the
9.1 Ship the samples in a rigid container with sufficient
leak test; then remove the entire inlet cap.
packing material to prevent jostling or damage. Care shall be
8.5 Conduct personal and area sampling as follows:
taken to minimize vibrations and cassette movement.
8.5.1 For personal sampling, fasten the sampling cassette to
NOTE 4—Do not use shipping material that may develop electrostatic
the worker’s lapel in the worker’s breathing zone and orient
forces or generate dust.
face down. Adjust the calibrated flow rate to a value between
NOTE 5—Shipping containers for 25-mm sampling cassettes are com-
0.5 and 4 L/min (2, 3). Typically, a sampling rate between 0.5
mercially available and their use is recommended.
and 2.5 L/min is selected (4-7).Also see Test Method D4532.
9.2 Include in the container a list of samples, their
8.5.2 Placeareasamplesonanextensionrodfacingdownat
descriptions, and all other pertinent information.
a 45° angle.Adjust the calibrated flow rate to a value between
0.5 and 16 L/min (2, 3). Typically, a sampling rate between 1
10. Specimen Preparation
and 10 L/min is selected (1).
10.1 Theobjectiveofthespecimenpreparationtechniqueis
to produce a thin carbon film (sufficiently clear for the TE
...
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