ASTM D6620-06(2010)
(Practice)Standard Practice for Asbestos Detection Limit Based on Counts
Standard Practice for Asbestos Detection Limit Based on Counts
SIGNIFICANCE AND USE
The DL concept addresses potential measurement interpretation errors. It is used to control the likelihood of reporting a positive finding of asbestos when the measured asbestos level cannot clearly be differentiated from the background contamination level. Specifically, a measurement is reported as being “below the DL” if the measured level is not statistically different than the background level.
The DL, along with other measurement characteristics such as bias and precision, is used when selecting a measurement method for a particular application. The DL should be established either at the method development stage or prior to a specific application of the method. The method developer subsequently would advertise the method as having a certain DL. An analyst planning to collect and analyze samples would, if alternative measurement methods were available, want to select a measurement method with a DL that was appropriate for the intended application. The most important use of the DL, therefore, takes place at the planning stage of a study, before samples are collected and analyzed.
SCOPE
1.1 This practice presents the procedure for determining the detection limit (DL) for measurements of fibers or structures using microscopy methods.
1.2 This practice applies to samples of air that are analyzed either by phase contrast microscopy (PCM) or transmission electron microscopy (TEM), and samples of dust that are analyzed by TEM.
1.3 The microscopy methods entail counting asbestos structures and reporting the results as structures per cubic centimeter of air (str/cc) or fibers per cubic centimeter of air (f/cc) for air samples and structures per square centimeter of surface area (str/cm2) for dust samples.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D6620 − 06 (Reapproved 2010)
Standard Practice for
1
Asbestos Detection Limit Based on Counts
This standard is issued under the fixed designation D6620; 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 for Asbestos Structure Number Surface Loading
D6281Test Method forAirborneAsbestos Concentration in
1.1 This practice presents the procedure for determining the
2 3 Ambient and Indoor Atmospheres as Determined by
detection limit (DL) for measurements of fibers or structures
TransmissionElectronMicroscopyDirectTransfer(TEM)
using microscopy methods.
D6480TestMethodforWipeSamplingofSurfaces,Indirect
1.2 This practice applies to samples of air that are analyzed
Preparation, and Analysis for Asbestos Structure Number
either by phase contrast microscopy (PCM) or transmission
Surface Loading by Transmission Electron Microscopy
electron microscopy (TEM), and samples of dust that are
E456Terminology Relating to Quality and Statistics
analyzed by TEM.
3. Terminology
1.3 The microscopy methods entail counting asbestos struc-
3.1 Definitions of Terms Specific to This Standard:
tures and reporting the results as structures per cubic centime-
3.1.1 average,n—thesumofasetofmeasurements(counts)
ter of air (str/cc) or fibers per cubic centimeter of air (f/cc) for
divided by the number of measurements in the set.
airsamplesandstructurespersquarecentimeterofsurfacearea
2
3.1.1.1 Discussion—The average is distinguished from the
(str/cm ) for dust samples.
mean. The average is calculated from data and serves as an
1.4 The values stated in SI units are to be regarded as
estimate of the mean. The mean (also referred to as the
standard. No other units of measurement are included in this
population mean, expected value,or first moment) is a param-
standard.
eter of the underlying statistical distribution of counts.
1.5 This standard does not purport to address all of the
3.1.2 background, n—a statistical distribution of structures
safety concerns, if any, associated with its use. It is the
introducedby(i)analystcountingerrorsand(ii)contamination
responsibility of the user of this standard to establish appro-
on an unused filter or contamination as a consequence of the
priate safety and health practices and determine the applica-
sample collection and sample preparation steps.
bility of regulatory limitations prior to use.
3.1.2.1 Discussion—This definition of background is spe-
cific to this practice. The only counting errors considered in
2. Referenced Documents
this definition of background are errors that result in an
4
2.1 ASTM Standards:
over-count(thatis,falsepositives).Analystcountingerrorsare
D1356Terminology Relating to Sampling and Analysis of
errors such as, determining the length of structures or fibers
Atmospheres
andwhether,basedonlength,theyshouldbecounted;counting
D5755TestMethodforMicrovacuumSamplingandIndirect
artifacts as fibers; determining the number of structures pro-
Analysis of Dust by Transmission Electron Microscopy
trudingfromamatrix;andinterpretingaclusterasone,two,or
more structures that should be counted only as zero or one
structure. For purposes of developing the DL, assume that
1
ThispracticeisunderthejurisdictionofASTMCommitteeD22onAirQuality
background contamination sources have been reduced to their
and is the direct responsibility of Subcommittee D22.07 on Sampling andAnalysis
of Asbestos. lowest achievable levels.
Current edition approved Oct. 1, 2010. Published November 2010. Originally
3.1.3 blank, n—a filter that has not been used to collect
approved in 2000. Last previous edition approved 2006 as D6620–06. DOI:
asbestos from the target environment.
10.1520/D6620-06R10.
2
The DL also is referred to in the scientific literature as Limit of Detection
3.1.3.1 Discussion—Blanks are used in this practice to
(LOD), Method Detection Limit (MDL), and other similar descriptive names.
determinethedegreeofasbestoscontaminationthatisreflected
3
For purposes of general exposition, the term “structures” will be used in place
inasbestosmeasurements.Contaminationmaybeonthevirgin
of “fibers or structures.” In the examples in Section 8, the specific term, “fiber” or
filter or introduced in handling the filter in the field or when
“structure,”isusedwhereappropriate.ThesetermsaredefinedseparatelyinSection
3.
preparing it for inspection with a microscope. The data
4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
required to determine the degree of contamination consists,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
therefore, of measurements of field bla
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.