ASTM D6480-99
(Test Method)Standard Test Method for Wipe Sampling of Surfaces, Indirect Preparation, and Analysis for Asbestos Structure Number Concentration by Transmission Electron Microscopy
Standard Test Method for Wipe Sampling of Surfaces, Indirect Preparation, and Analysis for Asbestos Structure Number Concentration by Transmission Electron Microscopy
SCOPE
1.1 This test method covers a procedure to identify asbestos in samples wiped from surfaces and to provide an estimate of the concentration of asbestos reported as the number of asbestos structures per unit area of sampled surface. The procedure outlined in this test method employs an indirect sample preparation technique. It is intended to disperse aggregated asbestos into fundamental fibrils, fiber bundles, clusters, or matrices. However, as with all indirect sample preparation techniques, the asbestos observed for quantification may not represent the physical form of the asbestos as sampled. More specifically, the procedure described neither creates nor destroys asbestos, but it may alter the physical form of the mineral fiber aggregates.
1.2 This test method describes the equipment and procedures necessary for wipe sampling of surfaces for levels of asbestos structures. The sample is collected onto a particle-free wipe material (wipe) from the surface of a sampling area that may contain asbestos.
1.2.1 The collection efficiency of this wipe sampling technique is unknown and will vary among substrates. Properties influencing collection efficiency include surface texture, adhesiveness, and other factors.
1.2.2 This test method is generally applicable for an estimate of the concentration of asbestos structures starting from approximately 1000 asbestos structures per square centimetre.
1.3 Asbestos identification by transmission electron microscopy (TEM) is based on morphology, electron diffraction (ED), and energy dispersive X-ray analysis (EDXA).
1.4 This test method allows determination of the type(s) of asbestos fibers present.
1.4.1 This test method cannot always discriminate between individual fibers of the asbestos and nonasbestos analogues of the same amphibole mineral.
1.4.2 There is no lower limit to the dimensions of asbestos fibers that can be detected. However, in practice, the lower limit to the dimensions of asbestos fibers, that can be detected, is variable and dependent on individual microscopists. Therefore, a minimum length of 0.5 m has been defined as the shortest fiber to be incorporated in the reported results.
This test method 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 test method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D6480–99
Standard Test Method for
Wipe Sampling of Surfaces, Indirect Preparation, and
Analysis for Asbestos Structure Number Concentration by
Transmission Electron Microscopy
This standard is issued under the fixed designation D 6480; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope is variable and dependent on individual microscopists. There-
fore, a minimum length of 0.5 µm has been defined as the
1.1 This test method covers a procedure to identify asbestos
shortest fiber to be incorporated in the reported results.
in samples wiped from surfaces and to provide an estimate of
1.5 This test method does not purport to address all of the
the concentration of asbestos reported as the number of
safety concerns, if any, associated with its use. It is the
asbestos structures per unit area of sampled surface. The
responsibility of the user of this test method to establish
procedure outlined in this test method employs an indirect
appropriate safety and health practices and determine the
sample preparation technique. It is intended to disperse aggre-
applicability of regulatory limitations prior to use.
gated asbestos into fundamental fibrils, fiber bundles, clusters,
or matrices. However, as with all indirect sample preparation
2. Referenced Documents
techniques, the asbestos observed for quantification may not
2.1 ASTM Standards:
represent the physical form of the asbestos as sampled. More
D 1193 Specification for Reagent Water
specifically, the procedure described neither creates nor de-
D 1356 Terminology Relating to Sampling and Analysis of
stroys asbestos, but it may alter the physical form of the
Atmospheres
mineral fiber aggregates.
D 3670 Guide for Determination of Precision and Bias of
1.2 This test method describes the equipment and proce-
Methods of Committee D-22
dures necessary for wipe sampling of surfaces for levels of
2.2 Government Standard:
asbestos structures.The sample is collected onto a particle-free
40 CFR 763, USEPA, Asbestos-Containing Materials in
wipe material (wipe) from the surface of a sampling area that
Schools: Final Rule and Notice, Appendix A to Sub-part
may contain asbestos.
E
1.2.1 The collection efficiency of this wipe sampling tech-
2.3 U.S. Environmental Protection Agency Standards:
nique is unknown and will vary among substrates. Properties
EPA600/4-83-043 AnalyticalMethodfortheDetermination
influencing collection efficiency include surface texture, adhe-
of Asbestos in Water
siveness, and other factors.
EPA747-R-95-001 USEPA, Residential Sampling for Lead:
1.2.2 This test method is generally applicable for an esti-
Protocols for Dust and Soil Sampling: Final Report
mate of the concentration of asbestos structures starting from
approximately 1000 asbestos structures per square centimetre.
3. Terminology
1.3 Asbestos identification by transmission electron micros-
3.1 Definitions—For definitions of general terms used in
copy(TEM)isbasedonmorphology,electrondiffraction(ED),
this test method, refer to Terminology D 1356.
and energy dispersive X-ray analysis (EDXA).
3.2 Definitions of Terms Specific to This Standard:
1.4 This test method allows determination of the type(s) of
3.2.1 amphibole asbestos—amphibole in an asbestiform
asbestos fibers present.
habit (1).
1.4.1 This test method cannot always discriminate between
3.2.2 analytical sensitivity—the calculated asbestos struc-
individual fibers of the asbestos and nonasbestos analogues of
ture concentration in asbestos structures/square centimetre,
the same amphibole mineral.
equivalent to counting of one asbestos structure in the analysis
1.4.2 There is no lower limit to the dimensions of asbestos
calculated using Eq 2.
fibers that can be detected. However, in practice, the lower
limit to the dimensions of asbestos fibers, that can be detected,
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 11.03.
1 4
This test method is under the jurisdiction of ASTM Committee D22 on Available from Superintendent of Documents, U.S. Government Printing
Sampling and Analysis of Atmospheres and is the direct responsibility of Subcom- Office, Washington, D.C. 20402.
mittee D22.07 on Sampling and Analysis of Asbestos. The boldface numbers in parentheses refer to the list of references at the end of
Current edition approved Dec. 10, 1999. Published March 2000. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6480–99
3.2.3 asbestos—a collective term that describes a group of haveanaspectratioequaltoorgreaterthan5:1andaminimum
naturally occurring, inorganic, highly fibrous, silicate minerals, length of 0.5 µm (see 40 CFR 763).
that are easily separated into long, thin, flexible, strong fibers
3.2.15 fibril—a single fiber, that cannot be further separated
when crushed or processed (1-3). longitudinally into smaller components without losing its
3.2.3.1 Discussion—Included in the definition are the as-
fibrous properties or appearances.
bestiform varieties of serpentine (chrysotile), riebeckite (cro-
3.2.16 fibrous mineral—a mineral composed of parallel,
cidolite), grunerite (grunerite asbestos [Amosite]), anthophyl-
radiating, or interlaced aggregates of fibers from which the
lite (anthophyllite asbestos), tremolite (tremolite asbestos), and
fibers are sometimes separable. That is, the crystalline aggre-
actinolite (actinolite asbestos). The amphibole mineral compo-
gate may be referred to as fibrous even if it is not composed of
sitions are defined in accordance with nomenclature of the
separable fibers but has that distinct appearance. The term
International Mineralogical Association (3,4).
fibrous is used in a general mineralogical way to describe
Asbestos Chemical Abstracts Service Registry No. aggregates of grains that crystallize in a needle-like habit and
Chrysotile 12001-29-5
appear to be composed of fibers. Fibrous has a much more
Crocidolite 12001-28-4
general meaning than asbestos. While it is correct that all
Grunerite Asbestos [Amosite] 12172-73-5
Anthophyllite Asbestos 77536-67-5 asbestos minerals are fibrous, not all minerals having fibrous
Tremolite Asbestos 77536-68-6
habits are asbestos.
Actinolite Asbestos 77536-66-4
3.2.17 fibrous structure—a fiber, or connected grouping of
3.2.4 asbestos structure—atermappliedtoisolatedfibersor
fibers, with or without other particles.
to any connected or overlapping grouping of asbestos fibers or
3.2.18 field wipe blank—a clean, unused, moistened wipe
bundles, with or without other nonasbestos particles.
from the same supply that is used for sampling. Field wipes
3.2.5 aspect ratio—the length to width ratio of a particle.
shall be processed in the same manner used to collect field
3.2.6 bundle—a structure composed of three or more fibers
samples with the exception that no surface is wiped. Each wipe
in a parallel arrangement with the fibers closer than one fiber
designated as a field wipe should be removed from the bulk
diameter to each other.
pack, moistened, and folded in the same manner as the field
3.2.7 camera length—the equivalent projection length be-
samples and placed in a sample container labeled as field wipe.
tween the specimen and its selection diffraction pattern, in the
3.2.19 filter blank—an unused, unprocessed filter of the
absence of lens action.
type used for liquid filtration.
3.2.8 chrysotile—a group of fibrous minerals of the serpen-
3.2.20 filtration blank—a filter prepared from 250 mL of
tine group that have the nominal composition Mg Si O (OH)
3 2 5 4
water.
and have the crystal structure of either clinochrysotile, ortho-
3.2.21 habit—the characteristic crystal growth form or
chrysotile, or parachrysotile. Most natural chrysotile deviates
combination of these forms of a mineral, including character-
little from this nominal composition. Chrysotile may be par-
istic irregularities.
tially dehydrated or magnesium-leached both in nature and in
3.2.22 indirect preparation—a method in which a sample
building materials. In some varieties of chrysotile, minor
3+ passes through one or more intermediate steps prior to final
substitution of silicon by Al may occur. Chrysotile is the
filtration. The particles are removed from the original medium
most prevalent type of asbestos.
and deposited on a second filter prior to analysis.
3.2.9 cluster—a structure with fibers in a random arrange-
3.2.23 limit of detection—the limit of detection for a mea-
ment such that all fibers are intermixed and no single fiber is
surement by this test method is 2.99 multiplied by the
isolated from the group; groupings of fibers must have more
analytical sensitivity for the measurement.
than two points touching.
3.2.23.1 Discussion—This limit of detection is based on the
3.2.10 d-spacing or inter-planar spacing—the perpendicu-
assumption that the count resulting from potential filter con-
lar distance between identical adjacent and parallel planes of
tamination, sample preparation contamination, and other un-
atoms in a crystal.
controllable background sources is no greater than 0.05 struc-
3.2.11 electron diffraction—techniques in electron micros-
tures per sample.At this time, however, this subcommittee has
copythatincludeselectedareaelectrondiffraction(SAED)and
no empirical data to confirm this rate.
microdiffraction by which the crystal structure of a specimen is
3.2.24 matrix—a structure in which one or more fibers, or
examined.
fiber bundles that are touching, are attached to, or partially
3.2.12 energy dispersive X-ray analysis—measurement of
concealed by, a single particle or connected group of nonfi-
the energies and intensities of X-rays by use of a solid state
brous particles. The exposed fiber must meet the fiber defini-
detector and multichannel analyzer system.
tion.
3.2.13 eucentric—the condition when the area of interest of
3.2.25 process blank—an unused wipe (that has not been
an object is placed on a tilting axis at the intersection of the
taken into the field) processed in accordance with the entire
electron beam at that axis and is in the plane of focus.
preparation and analytical procedure.
3.2.14 fiber—an elongate particle with parallel or stepped
3.2.26 replicate sampling—one of several identical proce-
sides. For the purposes of this test method, a fiber is defined to
dures or samples.
3.2.27 serpentine—a group of common rock-forming min-
erals having the nominal formula: Mg Si O (OH) . For further
The nonasbestiform variations of the minerals indicated in 3.2.3.1 have 3 2 5 4
different Chemical Abstract Service (CAS) numbers. information see Ref. (4).
D6480–99
3.2.28 structure—a single fiber, fiber bundle, cluster, or 5.1.2 At present, a single direct relationship between asbes-
matrix. tos sampled from a surface and potential human exposure does
3.2.29 structure number concentration—concentration ex- not exist. Accordingly, the user should consider these data in
pressed in terms of asbestos structure number per unit of relationship to other available information (for example, air
surface area. sampling data) in their evaluation.
3.2.30 zone-axis—the crystallographic direction of a crystal 5.2 One or more large asbestos-containing particles dis-
that is parallel to the intersecting edges of the crystal faces persed during sample preparation may result in large asbestos
defining the crystal zone. concentration results in the TEM analyses of that sample. It is,
3.3 Symbols: therefore, recommended that multiple replicate independent
samples be secured in the same area, and that a minimum of
three such samples be analyzed by the entire procedure.
eV = electron volt
h = hour
6. Interferences
J = joule
6.1 The following materials have properties (that is, chemi-
kV = kilovolt
cal composition or crystalline structure) that are very similar to
min = minute(s)
–3 asbestos minerals and may interfere with the analysis by
mL = millilitre (10 litre)
–6
causing a false positive to be recorded during the test.
µL = microlitre (10 litre)
–3
Therefore, literature references for these materials shall be
mm = millimetre (10 metre)
–6
maintained in the laboratory for comparison with asbestos
µm = micrometre (10 metre)
–9
mineralssothattheyarenotmisidentifiedasasbestosminerals.
nm = nanometre (10 metre)
6.1.1 Antigorite,
s = second(s)
W = watt
6.1.2 Fibrous talc,
Pa = pascals
6.1.3 Halloysite,
3.4 Acronyms: 6.1.4 Hornblende and other amphiboles,
6.1.5 Palygorskite (attapulgite),
6.1.6 Pyroxenes,
DMF = dimethyl formamide
6.1.7 Sepiolite, and
ED = electron diffraction
6.1.8 Vermiculite scrolls.
EDXA = energy dispersive X-ray analysis
FWHM = full width, half maximum
7. Apparatus
HEPA = High Efficiency Particulate Air
7.1 Equipment and Materials for Sampling:
MCE = mixed cellulose ester and also refers to pure
7.1.1 Disposable Wet Towels.
cellulose nitrate filters
7.1.2 Masking Tape.
PC = polycarbonate
7.1.3 Measuring Tape.
TEM = transmission electron microscope
7.1.4 Powderless, Rubber Gloves.
4. Summary of Test Method
7.1.5 Sample Container, clean, sealable, used for transport-
ing the sample to the laboratory.
4.1 Wiping a surface of known area with a wipe material
7.1.6 Template to Delineate Sampling Area, a reusable or
collects a sample. The sample is transferred from the wipe
disposable template of nonparticle-shedding material, such as
material to an aqueous suspension of known volume. Aliquots
aluminum, plastic, or nonshedding cardboard. A variety of
of the suspension are then filtered through a membrane filter.A
shapes (for example, square, rectangular) are acceptable. All
section of the membrane filter is prepared and transferred to a
templates shall have accurately known inside dimensions.
TEM grid, using the direct transfer method. The asbestiform
Templates should be thin (less than ⁄8 in. (3 mm)) and capable
structures are identified, sized, and counted by TEM, using ED
of lying flat on a flat surface. Clean reusable template before
and EDXA at a magnification from 15 000 to 20 000 3.
and after each use with a suitable cleaning method, such as
5. Significance and Use
surfactant solution or particle-free disposable wipe.
5.1 This wipe sampling and indirect analysis test method is 7.1.7 Wipe, particle free, sealed edge, continuous filament
used for the general testing of surfaces for asbestos. It is used cloth sampling medium. Satisfactory brands are available
to assist in the evaluation of surfaces in buildings, such as through commercial scientific suppliers. This material is com-
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