ASTM E2653-23

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2653 − 21 E2653 − 23 An American National Standard
Standard Practice for
Conducting an Interlaboratory Study to Determine Precision
Estimates for a Fire Test Method with Fewer Than Six
Participating Laboratories
This standard is issued under the fixed designation E2653; 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.
1. Scope
1.1 This practice describes the techniques for planning, conducting, analyzing, and treating results of an interlaboratory study
(ILS) for estimating the precision of a fire test method when fewer than six laboratories are available to meet the recommended
minimum requirements of Practice E691. Data obtained from an interlaboratory study are useful in identifying variables that
require modifications for improving test method performance and precision.
1.2 Precision estimates developed using this practice will not be statistically equivalent to precision estimates produced by Practice
E691 because a small number of laboratories are used. The smaller number of participating laboratories will seriously reduce the
value of precision estimates reported by this practice. However, under circumstances where only a limited number of laboratories
are available to participate in an ILS, precision estimates developed by this practice will provide the user with useful information
concerning precision for a test method.
1.3 A minimum of three qualified laboratories is required for conducting an ILS using this practice. If six or more laboratories
are available to participate in an ILS for a given fire test method, Practice E691 shall be used for conducting the ILS.
1.4 Since the primary purpose of this practice is the development of the information needed for a precision statement, the
experimental design in this practice will not be optimum for evaluating all materials, test methods, or as a tool for individual
laboratory analysis.
1.5 Because of the reduced number of participating laboratories, a Laboratory Monitor shall be used in the ILS. See Standard
Guide E2335.
1.6 Field of Application—This practice is concerned with test methods that yield numerical values or a series of numerical values
for different fire-test response properties. properties associated with the test method. The numerical values mentioned above are
typically the result of calculations from a set of measurements.
1.7 This practice includes design information suitable for use with the development of interlaboratory studies for test methods that
have categorization (go-no-go) allocation test results. However, it does not provide a recommended statistical practice for
evaluating the go-no-go data.
This practice is under the jurisdiction of ASTM Committee E05 on Fire Standards and is the direct responsibility of Subcommittee E05.31 on Terminology and Services
/ Functions.
Current edition approved Dec. 1, 2021March 1, 2023. Published January 2022March 2023. Originally approved in 2008. Last previous edition approved in 20152021 as
E2653E2653 – 21.-15. DOI: 10.1520/E2653-21.10.1520/E2653-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2653 − 23
1.8 This fire standard practice cannot be used to provide quantitative measures.
1.9 This practice is issued under Committee E05, but it is generic in its statistical approach such that it is applicable to any other
method.
1.10 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.
1.11 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.
2. Referenced Documents
2.1 ASTM Standards:
E176 Terminology of Fire Standards
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E178 Practice for Dealing With Outlying Observations
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1169 Practice for Conducting Ruggedness Tests
E2335 Guide for Laboratory Monitors
3. Terminology
3.1 Definitions—For formal definitions of statistical terms, see Terminology E456. For formal definitions of fire terms, see
Terminology E176.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 protocol, n—in this practice, directions given to the laboratories for conducting the interlaboratory study (ILS).
3.2.2 repeatability (of results and measurements), n—quantitative expression of the random variability associated with successive
measurements of the same measurand carried out subject to all of the following conditions: the same measurement procedure, the
same observer, the same measuring instrument, used under the same conditions, the same location, and repetition over a short
period of time.
3.2.2.1 Discussion—
Repeatability deals with results in a single laboratory while reproducibility deals with results obtained in different laboratories.
3.2.3 reproducibility (of results of measurements), n—quantitative expression of the random variability associated with successive
measurements of the same measurand carried out by operators working in different laboratories, each obtaining single results on
identical test material when applying the same method.
3.2.3.1 Discussion—
Repeatability deals with results in a single laboratory while reproducibility deals with results obtained in different laboratories.
3.2.4 test method, n—in this practice, description of the actual measurement process as well as written description of the process.
3.3 For further discussion of the terms discussed above, see Practice E177 and the formal definitions in Terminology E456.
4. Summary of Practice
4.1 The procedure presented in this practice consists of three basic steps: planning the interlaboratory study, guiding the testing
phase of the study, and analyzing the test result data. The analysis evaluates the consistency of the data through the use of numerical
estimates of precision of the test method pertaining to both within-laboratory repeatability and between-laboratory reproducibility.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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4.2 Planning of the interlaboratory study will include a review of the test procedure to be used in the interlaboratory study. This
review will identify portions of the test method that appear to contribute to a loss in precision. Special interlaboratory instructions
or modifications to the test method wording are made as needed to clarify these sections and often result in a modification to the
test method following the interlaboratory study.
4.3 A manager for the interlaboratory study and an interlaboratory test monitor shall be selected. The same person is allowed to
conduct both functions.
4.4 Parties conducting an interlaboratory precision study of a test method will acquire participation agreements with as many
laboratories as possible that are willing to take part in the interlaboratory study and have the capability to run the test method of
interest. A minimum of three laboratories shall participate in the precision study. Precision results will increase in quality with a
larger number of participating laboratories.
4.5 The types of materials and number of test specimens shall be selected for the interlaboratory study. No less than three test
specimens shall be selected for the interlaboratory study, and they shall be selected to reflect the range of performance of test
specimens normally evaluated by the test method. A minimum of three replicates shall be tested for each test material selected.
If a standard reference material is available for the test method, the material shall be included as a specimen in the interlaboratory
study. If a standard reference material is not available, a test specimen that consistently produces low variability test results shall
be selected as a reference material for the interlaboratory study.
5. Significance and Use
5.1 ASTM regulations require precision statements in all test methods in terms of repeatability and reproducibility. This practice
is used when the number of participating laboratories or materials being tested, or both, in a precision study is less than the number
specified by Practice E691. When possible, it is strongly recommended that a full Practice E691 standard protocol be followed to
determine test method precision. Precision results produced by the procedures presented in this standard will not have the same
degree of accuracy as results generated by a full Practice E691 protocol. This procedure will allow for the development of useful
precision results when a full complement of laboratories is not available for interlaboratory testing.
5.2 This practice is based on recommendations for interlaboratory studies and data analysis presented in Practice E691. This
practice does not concern itself with the development of test methods but with a standard means for gathering information and
treating the data needed for developing a precision statement for a fire test method when a complete Practice E691 interlaboratory
study and data analysis are not possible.
PLANNING THE ILS
6. Planning
6.1 Task Group—Either the task group that developed the test method or a special task group appointed for the purpose must have
overall responsibility for the ILS, including funding where appropriate, staffing, the design of the ILS, and decision-making with
regard to questionable data. The task group shall decide on the number of laboratories, materials, and test results for each material.
In addition, it shall specify any special calibration procedures and the repeatability conditions to be specified in the protocol.
6.2 ILS Coordinator—The task group must appoint one individual to act as overall coordinator for conducting the ILS. The
coordinator will supervise the distribution of materials and protocols to the laboratories and receive the test result reports from the
laboratories. Scanning the reports for gross errors and checking with the laboratories, when such errors are found, will also be the
responsibility of the coordinator. The coordinator will consult as needed with a statistician in questionable cases.
6.3 Laboratory Monitor—The task group must appoint one individual to act as a laboratory monitor for the ILS. The laboratory
monitor will develop an ILS checklist specific to the test method, inspect the test laboratories for equipment conformity and
operator training, verify compatibility of the data acquisition system, and based on the Checklist and inspection results report to
the sponsoring ASTM Subcommittee. Complete details for the function of a laboratory monitor are located in Guide E2335.
6.4 Statistician—The task group shall obtain the assistance of a person skilled in the use of statistical procedures, the test method
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being studied, and with the materials being tested in order to ensure that the requirements in this practice are met in an efficient
and effective manner. This person will conduct the data analysis using procedures given in this standard and will assist the task
group in interpreting results from the data analysis.
7. Basic Design
7.1 Keep the ILS design simple in order to obtain estimates of within-and between-laboratory variability that are free of secondary
effects. The basic design is represented by a two-way classification table in which the rows represent the laboratories, the columns
represent the materials, and the cell (the intersection of a row and column) contains the test results made by a particular laboratory
on a particular material (see Table 1).
7.2 An ILS using this practice shall include enough laboratories to represent a reasonable cross-section of the population of
qualified laboratories. A minimum of three laboratories is necessary for carrying out an ILS using this practice.
8. Test Method
8.1 Of prime importance is the existence of a valid, well-written test method that has been developed in one or more competent
laboratories, and had been subjected to a ruggedness test prior to the ILS.
8.2 The ruggedness test is a screening procedure for investigating the effects of variations in environmental and other conditions
in order to determine how control of such test conditions shall be specified in the written description of the method. Details for
ruggedness testing are found in Guide E1169.
8.3 A written version of the test method must be developed for the ILS (but not necessarily published as a standard method). This
draft shall describe the test apparatus and procedure in terms that are easily understood and followed in any properly equipped
laboratory by competent personnel with knowledge of the materials and the property to be tested. The method shall contain safety
and calibration procedures, details on control related limits that potentially cause test result variability, and specify how test results
are to be reported.
ILS TESTING
9. Pilot Run
9.1 Prior to beginning testing for the formal ILS a preliminary laboratory evaluation study shall be carried out using a well
characterized test material of known performance. This preliminary study is managed by the ILS Coordinator and Laboratory
Monitor and is used to determine if each of the participating laboratories are capable o
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