ASTM D7201-06(2020)
(Practice)Standard Practice for Sampling and Counting Airborne Fibers, Including Asbestos Fibers, in the Workplace, by Phase Contrast Microscopy (with an Option of Transmission Electron Microscopy)
Standard Practice for Sampling and Counting Airborne Fibers, Including Asbestos Fibers, in the Workplace, by Phase Contrast Microscopy (with an Option of Transmission Electron Microscopy)
SIGNIFICANCE AND USE
5.1 Users of this practice must determine for themselves whether the practices described meet the requirements of local or national authorities regulating asbestos or other fibrous hazards.
5.2 Variations of this practice have been described by the Asbestos Research Council in Great Britain (8), the Asbestos International Association (AIA) RTM 1 (9), NIOSH 7400, OSHA ID 160, and ISO 8672. Where the counting rules of the latter three methods differ, this is noted in the text.
5.3 Advantages:
5.3.1 The technique is specific for fibers. PCM is a fiber counting technique that excludes non-fibrous particles from the analysis.
5.3.2 The technique is inexpensive, but requires specialized knowledge to carry out the analysis for total fiber counts, at least in so far as the analyst is often required under regulations to have taken a specific training course (for example, NIOSH 582, or equivalent).
5.3.3 The analysis is quick and can be performed on-site for rapid determination of the concentrations of airborne fibers.
5.4 Limitations:
5.4.1 The main limitation of PCM is that fibers are not identified. All fibers within the specified dimensional range are counted. Differential fiber counting may sometimes be used to discriminate between asbestos fibers and fibers of obviously different morphology, such as cellulose and glass fiber. In most situations, differential fiber counting cannot be used to adequately differentiate asbestos from non-asbestos fibers for purposes of compliance with regulations without additional positive identification. If positive identification of asbestos is required, this must be performed by polarized light or electron microscopy techniques, using a different portion of the filter.
5.4.2 A further limitation is that the smallest fibers visible by PCM are about 0.2 μm in diameter, while the finest asbestos fibers may be as small as 0.02 μm in diameter.
5.4.3 Where calculation of fiber concentration provides a result exceed...
SCOPE
1.1 This practice2 describes the determination of the concentration of fibers, expressed as the number of such fibers per millilitre of air, using phase contrast microscopy and optionally transmission electron microscopy to evaluate particulate material collected on a membrane filter in the breathing zone of an individual or by area sampling in a specific location. This practice is based on the core procedures provided in the International Organization for Standardization (ISO) Standard ISO 8672 (1),3 the National Institute for Occupational and Health (NIOSH) Manual of Analytical Methods, NIOSH 7400 (2), and the Occupational Safety and Health Administration (OSHA) ID 160 (3). This practice indicates the important points where these methods differ, and provides information regarding the differences, which will allow the user to select the most appropriate procedure for a particular application. However, selecting portions of procedures from different published methods generally requires a user to report that they have used a modification to a method rather than claim they have used the method as written.
1.2 The practice is used for routine determination of an index of occupational exposure to airborne fibers in workplaces. Workplaces are considered those places where workers are exposed to airborne fibers including asbestos. Additional information on sampling strategies, sample collection (including calibration) and use of sample results for asbestos abatement projects is provided in a standard Practice for Air Monitoring for Management of Asbestos-Containing Materials (WK 8951) currently being considered by ASTM subcommittee E06.24. A further practice has been approved for the specific purpose of sampling and counting airborne fibers in mines and quarries (Practice D7200), although the practice herein may also be used for this purpose. The current practice may be used as a means of monitoring occupational exposure...
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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: D7201 − 06 (Reapproved 2020)
Standard Practice for
Sampling and Counting Airborne Fibers, Including Asbestos
Fibers, in the Workplace, by Phase Contrast Microscopy
(with an Option of Transmission Electron Microscopy)
This standard is issued under the fixed designation D7201; 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 tee E06.24. A further practice has been approved for the
specific purpose of sampling and counting airborne fibers in
1.1 This practice describes the determination of the con-
mines and quarries (Practice D7200), although the practice
centration of fibers, expressed as the number of such fibers per
herein may also be used for this purpose. The current practice
millilitreofair,usingphasecontrastmicroscopyandoptionally
may be used as a means of monitoring occupational exposure
transmission electron microscopy to evaluate particulate mate-
toasbestosfiberswhenasbestosfibersareknown a prioritobe
rial collected on a membrane filter in the breathing zone of an
present in the airborne dust. The practice gives an index of
individual or by area sampling in a specific location. This
airborne fiber concentration. This practice may be used in
practice is based on the core procedures provided in the
conjunction with electron microscopy (see Appendix X1) for
International Organization for Standardization (ISO) Standard
assistance in identification of fibers.This practice may be used
ISO 8672 (1), the National Institute for Occupational and
for other materials such as fibrous glass, or man-made mineral
Health (NIOSH) Manual ofAnalytical Methods, NIOSH 7400
fibers by using alternate counting rules (see Annex A4).
(2), and the Occupational Safety and Health Administration
(OSHA) ID160 (3). This practice indicates the important
1.3 Thispracticespecifiestheequipmentandproceduresfor
points where these methods differ, and provides information
samplingtheatmosphereinthebreathingzoneofanindividual
regarding the differences, which will allow the user to select
and for determining the number of fibers accumulated on a
the most appropriate procedure for a particular application.
filter membrane during the course of an appropriately-selected
However, selecting portions of procedures from different
sampling period. The practice may also be used to sample the
published methods generally requires a user to report that they
atmosphere in a specific location or room of a building (area
have used a modification to a method rather than claim they
sampling), where this may be helpful in assessing exposure to
have used the method as written.
workers handling fiber-containing products.
1.2 The practice is used for routine determination of an
1.4 The ideal working range of this test practice extends
index of occupational exposure to airborne fibers in work-
2 2
from 100 fibers/mm to 1300 fibers/mm of filter area. For a
places. Workplaces are considered those places where workers
1000-L air sample, this corresponds to a concentration range
are exposed to airborne fibers including asbestos. Additional
information on sampling strategies, sample collection (includ- from approximately 0.04 to 0.5 fiber/mL(or fiber/cm ). Lower
and higher ranges of fiber concentration can be measured by
ing calibration) and use of sample results for asbestos abate-
ment projects is provided in a standard Practice for Air reducing or increasing the volume of air collected. However,
Monitoring for Management ofAsbestos-Containing Materials whenthispracticeisappliedtosamplingthepresenceofother,
(WK 8951) currently being considered by ASTM subcommit-
non-asbestos dust, the level of total suspended particulate may
impose an upper limit to the volume of air that can be sampled
if the filters produced are to be of appropriate fiber loading for
fiber counting.
ThispracticeisunderthejurisdictionofASTMCommitteeD22onAirQuality
and is the direct responsibility of Subcommittee D22.07 on Sampling, Analysis,
1.5 Users should determine their own limit of detection
Management of Asbestos, and Other Microscopic Particles.
Current edition approved April 15, 2020. Published April 2020. Originally
using the procedure in Practice D6620. For Reference the
approved in 2006. Last previous edition approved in 2011 as D7201–06 (2011).
NIOSH 7400 method gives the limit of detection as 7 fibers/
DOI: 10.1520/D7201-06R20.
2 mm offilterarea.Fora1000Lairsample,thiscorrespondsto
This practice is based on NIOSH 7400, OSHAID160, and ISO 8672. Users of
this ASTM standard are cautioned that if they wish to comply with one of these
a limit of detection of 0.0027 fiber/mL (or fiber/cm ). For
specificproceduresexactlytheyshouldfollowthatprocedure,otherwisetheyshould
OSHAID160 the limit of detection is given as 5.5 fibers/mm
document the modification
3 of filter area. For a 1000 L air sample, this corresponds to a
The boldface numbers in parentheses refer to a list of references at the end of
this standard. limit of detection of 0.0022 fiber/mL (or fiber/cm ).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7201 − 06 (2020)
1.6 If this practice yields a fiber concentration that does not 2.2 Other Standards:
exceed the occupational limit value for the particular regulated NIOSH 7400National Institute for Occupational Health and
fiber variety, no further action may be necessary. If the fiber Safety (NIOSH), (Revised 1994)
concentration exceeds the occupational limit value for a Recommended Technical Method No.1 (RTM 1)Asbestos
International Association (AIA)
specific fiber variety, and there is reason to suspect that the
specific fiber variety is mixed with other fibers not covered ID 160 Occupational Safety and Health Administration
(OSHA)
under the same standard or regulation, the optional method
specified in Appendix X1 may be used to measure the ISO 8672International Organization for Standardization
(ISO)
concentrationorproportionofthefiberscountedthatareofthe
regulated variety.
3. Terminology
1.7 The mounting medium used in this practice has a
3.1 Description of Terms Specific to This Standard—In
refractive index of approximately 1.45. Fibers with refractive
addition to those found in Terminology D1356:
indices in the range of 1.4 to 1.5 will exhibit reduced contrast,
3.1.1 area sample, n—an air sample collected so as to
and may be difficult to detect.
representtheconcentrationofairbornedustinaspecificareaor
room, which, in the case of this practice, refers to an area or
1.8 Fibers less than approximately 0.2 µm in diameter will
room of a workplace.
not be detected by this practice (4).
3.1.2 asbestiform, n—a specific type of fibrous mineral
1.9 The values stated in SI units are to be regarded as
growth habit in which the fibers and fibrils exhibit a polyfila-
standard. No other units of measurement are included in this
mentous growth habit and possess high tensile strength and
standard.
flexibility. All materials regulated as asbestos are asbestiform,
1.10 This standard does not purport to address all of the
but not all asbestiform minerals are classified as asbestos.
safety concerns, if any, associated with its use. It is the
Characteristicssuchastensilestrengthandflexibilitycannotbe
responsibility of the user of this standard to establish appro-
ascertained from microscopic evaluation.
priate safety, health, and environmental practices and deter-
3.1.3 asbestos, n—a term applied to six specific silicate
mine the applicability of regulatory limitations prior to use.
minerals belonging to the serpentine and amphibole groups,
For specific precautionary statements, see Section 7.
which have crystallized in the asbestiform habit, causing them
1.11 This international standard was developed in accor-
to be easily separated into long, thin, flexible, strong fibers
dance with internationally recognized principles on standard-
when crushed or processed (5). The Chemical Abstracts
ization established in the Decision on Principles for the
Service Registry Numbers of the most common asbestos
Development of International Standards, Guides and Recom-
varieties are: chrysotile (12001-29-5), riebeckite asbestos (cro-
mendations issued by the World Trade Organization Technical
cidolite) (12001-28-4), grunerite asbestos (Amosite) (12172-
Barriers to Trade (TBT) Committee.
73-5), anthophyllite asbestos (77536-67-5), tremolite asbestos
(77536-68-6) and actinolite asbestos (77536-66-4).
2. Referenced Documents
The precise chemical composition of each species varies
4 with the location from which it was mined. Other amphibole
2.1 ASTM Standards:
minerals that exhibit the characteristics of asbestos have also
D257Test Methods for DC Resistance or Conductance of
been observed (6).
Insulating Materials
The nominal compositions of the most common asbestos
D1356Terminology Relating to Sampling and Analysis of
varieties are:
Atmospheres
Chrysotile Mg Si O (OH)
3 2 5 4
D1357Practice for Planning the Sampling of the Ambient
2+ 3+
Crocidolite Na Fe Fe Si O (OH)
2 3 2 8 22 2
Atmosphere
Amosite (Mg,Fe) Si O (OH)
7 8 22 2
Anthophyllite (Mg,Fe) Si O (OH)
D3670Guide for Determination of Precision and Bias of 7 8 22 2
2+
Tremolite Ca (Mg,Fe) Si O (OH) (Mg/(Mg + Fe ) 0.9 - 1.0)
2 5 8 22 2
Methods of Committee D22
2+
Actinolite Ca (Mg,Fe) Si O (OH) (Mg/(Mg + Fe ) 0.5 - 0.9)
2 5 8 22 2
D5337Practice for Flow RateAdjustment of Personal Sam-
3.1.3.1 Discussion—Actinolite compositions in which Mg/
pling Pumps
2+
(Mg+Fe ) is between 0 and 0.5 are referred to as ferroacti-
D6620Practice for Asbestos Detection Limit Based on
nolite.SeeRef. (7)forthefullnamingconventionsspecifiedby
Counts
the International Mineralogical Association.
D7200Practice for Sampling and CountingAirborne Fibers,
Including Asbestos Fibers, in Mines and Quarries, by 3.1.4 asbestos fiber, n—a fiber of asbestos, which meets the
Phase Contrast Microscopy and Transmission Electron criteria specified below for a fiber. Phase Contrast Microscopy
Microscopy (PCM) does not identify fibers as asbestos. Under the light
microscope, a population of asbestos fibers may appear as a
4 5
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from United States Department of Health and Human Services
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM (HHS), 200 Independence Ave., SW, Washington, DC 20201, http://www.hhs.gov.
Standards volume information, refer to the standard’s Document Summary page on Available from Asbestos International Association, 68 Gloucester Place,
the ASTM website. London, W1H 3HL, England.
D7201 − 06 (2020)
mixture of fiber agglomerates, fiber bundles (polyfilamentous area of 0.00785 mm ) with a cross-hair having tick-marks at
growth, unique to asbestiform fibers), fibers with split ends, 3-µm intervals in one direction and 5-µm intervals in the
andsinglefibers,therelativeoccurrenceandfrequencyofeach orthogonal direction. There are also examples around the
type depending on the situation. periphery of the circle to illustrate specific sizes and shapes of
fibers. This design of the graticule is shown in Fig. A1.1. The
3.1.5 aspect ratio, n—the ratio of the length of a fiber to its
graticule is placed in one of the microscope eyepieces so that
width.
the design is superimposed on the field of view.
3.1.6 differential counting, n—a term applied to the practice
of excluding certain kinds of fibers from the fiber count 4. Summary of Practice
because they do not appear to be morphologically consistent
4.1 Thesampleiscollectedbydrawingairthrougha25-mm
withfibersofaspecificvarietythusmodifyingthedefinitionof
diameter,mixedcelluloseester(MCE)membranefilter,housed
fiber given below.
in a conductive polypropylene cassette. After sampling, a
3.1.7 fiber, n—an elongated particle that is longer than 5.0
sector of the membrane filter is converted to an optically
µm, with a minimum aspect ratio of 3:1, and sometimes also
transparent homogeneous gel. Fibers longer than 5 µm are
classified as having a maximum width of 3.0 µm as this latter
counted by observing them with a PCM at a magnification
dimension may equate to the size of fiber, of the density of
between 400 and 500.
many silicate minerals, capable of penetrating to the lung. An
5. Significance and Use
asbestos fiber should further exhibit the asbestiform habit,
although analysis of airborne fibers by PCM may not be
5.1 Users of this practice must determine for themselves
sufficient to determine asbestiform habit. whether the practices described meet the requirements of local
or national authorities regulating asbestos or other fibrous
3.1.8 fibril, n—a single fiber of asbestos that cannot be
hazards.
further separated longitudinally into smaller components with-
out losing its fibrous properties or appearances.
5.2 Variations of this practice have been described by the
Asbestos Research Council in Great Britain (8), the Asbestos
3.1.9 fibrous, adj—ahabitofmineralscomposedofparallel,
International Association (AIA) RTM 1 (9), NIOSH 7400,
radiating, or interlaced aggregates of fibers, from which the
OSHAID160, and ISO 8672. Where the counting rules of the
fibers are sometimes separable.Acrystalline aggregate may be
latter three methods differ, this is noted in the text.
referred to as fibrous even if it is not composed of separable
fibers, but has that distinct appearance. The term “fibrous” in
5.3 Advantages:
mineralogy is used to describe aggregates of mineral grains
5.3.1 The technique is specific for fibers. PCM is a fiber
that crystallize in a needle-like habit and appear to be com-
countingtechniquethatexcludesnon-fibrousparticlesfromthe
posed of fibers. Asbestos minerals are fibrous, exhibiting a
analysis.
specifictypeoffibroushabittermedasbestiform.However,not
5.3.2 The technique is inexpensive, but requires specialized
all minerals having fibrous habit are asbestos.
knowledge to carry out the analysis for total fiber counts, at
3.1.10 field (of view), n—the area within a graticule circle least in so far as the analyst is often required under regulations
to have taken a specific training course (for example, NIOSH
that is superimposed on the microscope image.
582, or equivalent).
3.1.11 habit, n—the characteristic crystal growth form or
5.3.3 Theanalysisisquickandcanbeperformedon-sitefor
combination of these forms of a mineral, including character-
rapid determination of the con
...
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