ASTM D6689-01(2019)e1
(Guide)Standard Guide for Optimizing, Controlling, and Reporting Test Method Uncertainties from Multiple Workstations in the Same Laboratory Organization
Standard Guide for Optimizing, Controlling, and Reporting Test Method Uncertainties from Multiple Workstations in the Same Laboratory Organization
SIGNIFICANCE AND USE
4.1 Many analytical laboratories comply with accepted quality system requirements such as NELAC, Chapter 5,5 (see Note 2) and ISO/IEC 17025. When using standard test methods, their test results on the same sample should agree with those from other similar laboratories within the reproducibility estimates (R2) published in the standard. Reproducibility estimates are generated during the standardization process as part of the interlaboratory studies (ILS). Many laboratories participate in proficiency tests to confirm that they perform consistently over time. In both ILS and proficiency testing protocols, it is generally assumed that only one workstation is used to generate the data (see 6.5.1).
Note 2: NELAC, Chapter 5, allows the use of a Work Cell where multiple instruments/operators are treated as one unit: the performance of the Work Cell is tracked rather than each workstation independently. This guide is intended to go beyond the Work Cell to achieve the benefits of monitoring workstations independently.
4.2 Many laboratories have workloads or logistical requirements, or both, that dictate the use of multiple workstations. Some have multiple stations in the same area (central laboratory format). Others’ stations are scattered throughout a facility (at-line laboratory format). Often, analysis reports do not identify the workstation used for the testing, even if workstations differ in their testing uncertainties. Problems can arise if clients mistakenly attribute variation in report values to process rather then workstation variability. These problems can be minimized if the laboratory organization sets, complies with, and reports a unified set of measurement quality objectives throughout.
4.3 This guide can be used to harmonize calibration and control protocols for all workstations, thereby providing the same level of measurement traceability and control. It streamlines documentation and training requirements, thereby facilitating flexibility in personnel...
SCOPE
1.1 This guide describes a protocol for optimizing, controlling, and reporting test method uncertainties from multiple workstations in the same laboratory organization. It does not apply when different test methods, dissimilar instruments, or different parts of the same laboratory organization function independently to validate or verify the accuracy of a specific analytical measurement.
1.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.3 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.
General Information
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Standards Content (Sample)
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.
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Designation: D6689 − 01 (Reapproved 2019)
Standard Guide for
Optimizing, Controlling, and Reporting Test Method
Uncertainties from Multiple Workstations in the Same
Laboratory Organization
This standard is issued under the fixed designation D6689; 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 (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Reapproved with editorial changes throughout in March 2019.
1. Scope E415 Test Method for Analysis of Carbon and Low-Alloy
Steel by Spark Atomic Emission Spectrometry
1.1 This guide describes a protocol for optimizing,
E1763 Guide for Interpretation and Use of Results from
controlling, and reporting test method uncertainties from mul-
Interlaboratory Testing of Chemical Analysis Methods
tiple workstations in the same laboratory organization. It does
(Withdrawn 2015)
not apply when different test methods, dissimilar instruments,
2.2 Other Documents:
or different parts of the same laboratory organization function
ISO/IEC 17025 General Requirements for the Competence
independently to validate or verify the accuracy of a specific
of Calibration and Testing Laboratories
analytical measurement.
MNL7-9TH ASTM Manual on Presentation of Data and
1.2 This standard does not purport to address all of the
ControlChartAnalysis,9thEdition,PreparedbyCommit-
safety concerns, if any, associated with its use. It is the
tee E11 on Quality and Statistics
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3. Terminology
mine the applicability of regulatory limitations prior to use.
3.1 Definitions—For definitions of terms used in this Guide,
1.3 This international standard was developed in accor-
refer to Terminologies E135 and D1129.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3.2 Definitions of Terms Specific to This Standard:
Development of International Standards, Guides and Recom-
3.2.1 laboratory organization, n—a business entity that
mendations issued by the World Trade Organization Technical
provides similar types of measurements from more than one
Barriers to Trade (TBT) Committee.
workstation located in one or more laboratories, all of which
operate under the same quality system.
2. Referenced Documents
NOTE1—KeyaspectsofaqualitysystemarecoveredinISO/IEC17025
2.1 ASTM Standards:
and include documenting procedures, application of statistical control to
D1129 Terminology Relating to Water measurement processes and participation in proficiency testing.
D6091 Practice for 99 %/95 % Interlaboratory Detection
3.2.2 maximum deviation, n—themaximumerrorassociated
Estimate (IDE) for Analytical Methods with Negligible
with a report value, at a specified confidence level, for a given
Calibration Error
concentration of a given element, determined by a specific
D6512 Practice for Interlaboratory Quantitation Estimate
method, throughout a laboratory organization.
E135 Terminology Relating to Analytical Chemistry for
3.2.3 measurement quality objectives, n—a model used by
Metals, Ores, and Related Materials
the laboratory organization to specify the maximum error
associated with a report value, at a specified confidence level.
1 3.2.4 workstation, n—a combination of people and equip-
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
thedirectresponsibilityofSubcommitteeD19.02onQualitySystems,Specification, ment that executes a specific test method using a single
and Statistics.
specifiedmeasuringdevicetoquantifyoneormoreparameters,
Current edition approved March 15, 2019. Published April 2019. Originally
approved in 2001. Last previous edition approved in 2011 as D6689 – 01 (2011).
DOI: 10.1520/D6689-01R19E01.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6689 − 01 (2019)
with each report value having an established estimated uncer- 4.6 The general principles of this protocol can be adapted to
taintythatcomplieswiththemeasurementqualityobjectivesof other types of measurements, such as mechanical testing and
the laboratory organization. on-line process control measurements such as temperature and
thickness gauging. In these areas, users will likely need to
establish their own models for defining measurement quality
4. Significance and Use
objectives. Proficiency testing may not be available or appli-
4.1 Many analytical laboratories comply with accepted
cable.
quality system requirements such as NELAC, Chapter 5, (see
4.7 It is especially important that users of this guide take
Note 2) and ISO/IEC 17025. When using standard test
responsibility for ensuring the accuracy of the measurements
methods, their test results on the same sample should agree
with those from other similar laboratories within the reproduc- madebytheworkstationstobeoperatedunderthisprotocol.In
addition to the checks mentioned in 6.2.3, laboratories are
ibility estimates (R2) published in the standard. Reproducibil-
ity estimates are generated during the standardization process encouraged to use other techniques, including, but not limited
to, analyzing some materials by independent methods, either
as part of the interlaboratory studies (ILS). Many laboratories
participate in proficiency tests to confirm that they perform within the same laboratory or in collaboration with other
equally competent laboratories. The risks associated with
consistently over time. In both ILS and proficiency testing
generating large volumes of data from carefully harmonized,
protocols, it is generally assumed that only one workstation is
but incorrectly calibrated multiple workstations are obvious
used to generate the data (see 6.5.1).
and must be avoided.
NOTE 2—NELAC, Chapter 5, allows the use of a Work Cell where
multiple instruments/operators are treated as one unit: the performance of
5. Summary
the Work Cell is tracked rather than each workstation independently. This
5.1 Identify the Test Method and establish the required
guide is intended to go beyond the Work Cell to achieve the benefits of
monitoring workstations independently. measurement quality objectives to be met throughout the
laboratory organization.
4.2 Many laboratories have workloads or logistical
requirements, or both, that dictate the use of multiple worksta-
5.2 Identify the workstations to be included in the protocol
tions. Some have multiple stations in the same area (central
and harmonize their experimental procedures, calibrations and
laboratory format). Others’ stations are scattered throughout a
control strategies to be identical, so they will be statistically
facility (at-line laboratory format). Often, analysis reports do
comparable.
not identify the workstation used for the testing, even if
5.3 Tabulate performance data for each workstation and
workstations differ in their testing uncertainties. Problems can
ensure that each workstation complies with the laboratory
arise if clients mistakenly attribute variation in report values to
organization’s measurement quality objectives.
processratherthenworkstationvariability.Theseproblemscan
5.4 Document items covered in 5.1 – 5.3.
be minimized if the laboratory organization sets, complies
with, and reports a unified set of measurement quality objec-
5.5 Establish and document a laboratory organization-wide
tives throughout.
Proficiency Test Policy that provides traceability to all work-
stations.
4.3 This guide can be used to harmonize calibration and
control protocols for all workstations, thereby providing the
5.6 Operate each workstation independently as described in
same level of measurement traceability and control. It stream-
its associated documentation. If any changes are made to any
lines documentation and training requirements, thereby facili-
workstation or its performance levels, document the changes
tating flexibility in personnel assignments. Finally, it offers an
and ensure compliance with the laboratory organization’s
opportunity to claim traceability of proficiency test measure-
measurement quality objectives.
ments to all included workstations, regardless on which work-
6. Procedure
station the proficiency test sample was tested. The potential
6.1 Identify the Test Method and establish the measurement
benefits of utilizing this protocol increase with the number of
workstations included in the laboratory organization. quality objectives to be met throughout the laboratory organi-
zation.
4.4 This guide can be used to identify and quantify benefits
6.1.1 Multi-element test methods can be handled
derived from corrective actions relating to under-performing
concurrently, if all elements are measured using common
workstations. It also provides means to track improved perfor-
technology, and the parameters that influence data quality are
mance after improvements have been made.
tabulated and evaluated for each element individually. An
4.5 It is a prerequisite that all users of this guide comply
example is Test Method E415 that covers the analysis of plain
with ISO/IEC 17025, especially including the use of docu-
carbon and low alloy steel by optical emission vacuum
mented procedures, the application of statistical control of
spectrometry. Workstations can be under manual or robotic
measurement processes, and participation in proficiency test-
control, as long as the estimated uncertainties are within the
ing.
specified measurement quality objectives. Avoid handling
multi-element test methods that concurrently use different
measurement technologies. Their procedures and error evalu-
ations are too diverse to be incorporated into one easy-to-
Available from The NELAC Institute (TNI), P.O. Box 2439, Weatherford, TX
76086, https://www.nelac-institute.org. manage package.
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D6689 − 01 (2019)
TABLE 1 Continued
6.1.2 Set the measurement quality objectives for the use of
Assumed
the Test Method throughout the laboratory organization, using
Std.
ERM True WS Av. UCL LCL
Dev.
customer requirements and available performance data. At the
Conc.
conclusion of this effort, the laboratory organization will know
648 0.25063 1 0.25174 0.25906 0.24442 0.00244
the maximum deviation allowable for any report value, at any 2 0.24891 0.25350 0.24432 0.00153
3 0.25123 0.25927 0.24319 0.00268
concentrationlevel,usingthemethodofchoice.Anexampleof
Cr 638 0.03746 1 0.03760 0.03886 0.03634 0.00042
a possible method for establishing measurement quality objec-
2 0.03745 0.03832 0.03658 0.00029
tives is given in Appendix X1. 3 0.03732 0.03813 0.03651 0.00027
648 0.23728 1 0.23190 0.23637 0.22743 0.00149
6.2 Identify the workstations to be included in the protocol 2 0.24012 0.24414 0.23610 0.00134
3 0.23982 0.24300 0.23664 0.00106
and harmonize their experimental procedures, calibrations and
Sn 638 0.00278 1 0.00255 0.00507 0.00003 0.00084
control strategies so that all performance data from all work-
2 0.00257 0.00296 0.00218 0.00013
stations are directly statistically comparable. 3 0.00322 0.00490 0.00154 0.00056
648 0.01424 1 0.01402 0.01600 0.01204 0.00066
6.2.1 For each workstation, list the parameters (personnel,
2 0.01412 0.01502 0.01322 0.00030
equipment, etc.) that significantly influence data quality. Each
3 0.01458 0.01668 0.01248 0.00070
Mo 638 0.06346 1 0.06253 0.06604 0.05902 0.00117
component of each workstation does not have to be identical
2 0.06398 0.06533 0.06263 0.00045
(such as from the same manufacturer or model number).
3 0.06387 0.06621 0.06153 0.00078
However, each workstation must perform the functions de-
648 0.08652 1 0.08539 0.08995 0.08083 0.00152
2 0.08722 0.08941 0.08503 0.00073
scribed in the test method.
3 0.08696 0.09011 0.08381 0.00105
6.2.2 Harmonize the experimental procedures associated
V 638 0.02107 1 0.02076 0.02184 0.01968 0.00036
2 0.02114 0.02219 0.02009 0.00035
with each workstation to ensure that all stations are capable of
3 0.02132 0.02231 0.02033 0.00033
generatingstatisticallycomparabledatathatcanbeexpectedto
648 0.06937 1 0.06892 0.07123 0.06661 0.00077
fall within the maximum allowable limits for the laboratory
2 0.06949 0.07219 0.06679 0.00090
3 0.06969 0.07233 0.06705 0.00088
organization. Ideally, all workstations within the laboratory
Ti 638 0.00224 1 0.00272 0.00296 0.00248 0.00008
organization will have essentially the same experimental pro-
2 0.00200 0.00200 0.00200 0.00000
cedures.
3 0.00200 0.00200 0.00200 0.00000
TABLE 1 Sample SPC Control Parameter Tabulation 648 0.04279 1 0.04285 0.04726 0.03844 0.00147
2 0.04285 0.04684 0.03886 0.00133
Assumed
Std. 3 0.04268 0.04688 0.03848 0.00140
ERM True WS Av. UCL LCL
Dev. Al 638 0.02346 1 0.02373 0.02964 0.01782 0.00197
Conc.
2 0.02343 0.02646 0.02040 0.00101
C 638 0.06014 1 0.05996 0.06764 0.05228 0.00256
3 0.02323 0.02584 0.02062 0.00087
2 0.06040 0.06364 0.05716 0.00108
648 0.06268 1 0.06268 0.06721 0.05815 0.00151
3 0.06005 0.06308 0.05702 0.00101
2 0.06198 0.06633 0.05763 0.00145
648 0.25665 1 0.25212 0.27069 0.23355 0.00619
3 0.06222 0.06576 0.05868 0.00118
2 0.25923 0.27402 0.24444 0.00493
3 0.25861 0.27283 0.24439 0.00474
E = Element determined
Mn 638 0.29832 1 0.29620 0.30304 0.28936 0.00228
RM = Reference material used for SPC control
2 0.29967 0.30567 0.29367 0.00200
Assumed True Conc. = Concentration of E in the RM
3 0.29908 0.30643 0.29173 0.00245
WS = Work Station
648 0.90328 1 0.90408 0.92088 0.88728 0.00564
Av. = Grand Mean from the SPC chart
2 0.90408 0.92385 0.88431 0.00659
UCL = Upper control limit from the SPC chart
3 0.90168 0.92664 0.87672 0.00832
LCL = Lower control limit from the SPC chart
P 638 0.00563 1 0.00543 0.00600 0.00486 0.00019
Std. Dev. = Standard Deviation from the SPC chart {(UCL-LCL)/6}
2 0.00575 0.00605 0.00545 0.00010
6.2.3 Harmonize calibration protocols so that equivalent
3 0.00571 0.00601 0.00541 0.00010
648 0.03431 1 0.03413 0.03674 0.03152 0.00087
calibrants (that is, same material
...
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