ASTM D7235-21a
(Guide)Standard Guide for Establishing a Linear Correlation Relationship Between Analyzer and Primary Test Method Results Using Relevant ASTM Standard Practices
Standard Guide for Establishing a Linear Correlation Relationship Between Analyzer and Primary Test Method Results Using Relevant ASTM Standard Practices
SIGNIFICANCE AND USE
4.1 This guide is intended to be used in conjunction with Practice D3764 (Case 1) and Practice D6122 (Case 2). Methodology in this guide can be used to determine if a linear correlation can improve the performance of the total analyzer system in terms of its ability to predict the results that the PTM would have been if applied to the same material. This methodology, which is based on the same statistical data treatment as Practice D6708, is used to derive the parameters of the linear relationship and to assess the degree of improvement.
4.2 This guide provides developers or manufacturers of process stream analyzer systems with useful procedures for developing the capability of newly designed systems for industrial applications that require reliable prediction of measurements of a specific property by a primary test method of a flowing component or product.
4.3 This guide provides purchasers of process stream analyzer systems with some reliable options for specifying performance requirements for process stream analyzer systems that are used in applications requiring reliable prediction of measurements of a specific property by a primary test method of a flowing component or product.
4.4 This guide provides the user of a process stream analyzer system with useful information on the work process for establishing the PTM prediction relationship and prediction performance.
4.5 Prediction (correlation) relationship obtained in the application of this guide is applicable only to the material type and property range of the materials used to perform the study. Selection of the property levels and the compositional characteristics of the samples must be suitable for the application of the analyzer system. Users are cautioned against extrapolation of the prediction relationship beyond the material type and property range used to obtain the relationship.
4.6 The degree-of-agreement assessment promoted in this guide is based on the statistical principles articula...
SCOPE
1.1 This guide covers a general methodology to develop and assess the linear relationship between results produced by a total analyzer system versus the results produced by the corresponding primary test method (PTM) that the analyzer system is intended to emulate, using the principles and approaches outlined in relevant ASTM standard practices and guides.
1.2 This guide describes how the statistical methodology of Practice D6708 can be employed to assess agreement between the PTM and analyzer results, and, if necessary, develop linear correlation to further improve the agreement over the complete operating range of the analyzer. For instances where there is insufficient variation in property level to apply the Practice D6708 multi-level methodology, users are referred to Practice D3764 to perform a level specific bias evaluation. The correlation relationship information obtained in the application of this guide is applicable only to the material type and property range of the materials representative of those used to perform the assessment. Users are cautioned against extrapolation of the relationship beyond the material type and property range being studied.
1.3 This guide applies if the process stream analyzer system and the primary test method are based on the same measurement principle(s), or, if the process stream analyzer system uses a direct and well-understood measurement principle that is similar to the measurement principle of the primary test method. If the process stream analyzer system uses a different measurement technology from the primary test method, provided that the calibration protocol for the direct output of the analyzer does not require use of the PTM, this practice also applies.
1.4 This guide does not apply if the process stream analyzer system utilizes an indirect or mathematically modeled measurement principle such as chemometric or multivariate analysis techniques where results from ...
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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: D7235 − 21a
Standard Guide for
Establishing a Linear Correlation Relationship Between
Analyzer and Primary Test Method Results Using Relevant
1
ASTM Standard Practices
This standard is issued under the fixed designation D7235; 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.
INTRODUCTION
Operation of a process stream analyzer system typically involves four sequential activities: (1)
Analyzer Calibration—When an analyzer is initially installed, or after major maintenance has been
performed, diagnostic testing will typically be performed to demonstrate that the analyzer meets
manufacturer’sspecificationsandhistoricalperformancestandards.Thesediagnostictestsmayrequire
that the analyzer be adjusted so as to provide predetermined output levels for certain reference
materials. (2) Correlation to Primary Test Method—For process stream analyzer systems where the
application objective is to provide prediction of results from a Primary Test method, once the
diagnostic testing is completed, process stream samples will typically be analyzed using both the
analyzer system and the corresponding primary test method.Amathematical function will be derived
thatrelatestheanalyzeroutputtotheprimarytestmethod(PTM).Theapplicationofthismathematical
function to an analyzer output produces a predicted PTM result. (3) Initial Validation—Once the
relationship between the analyzer output and primary test method results has been established, an
initial validation is performed using an independent data set to demonstrate that the predicted PTM
results agree with those from the primary test method within the tolerances established from the
Correlation activities and with no statistically observable systemic bias. (4) Continual Validation—
During normal operation of the process analyzer system, quality assurance testing is conducted to
demonstrate that the agreement between analyzer and primary test method results during the Initial
Validation is maintained. This document provides guidance for item (2) above.
1. Scope* operating range of the analyzer. For instances where there is
insufficient variation in property level to apply the Practice
1.1 Thisguidecoversageneralmethodologytodevelopand
D6708 multi-level methodology, users are referred to Practice
assess the linear relationship between results produced by a
D3764 to perform a level specific bias evaluation. The corre-
total analyzer system versus the results produced by the
lation relationship information obtained in the application of
corresponding primary test method (PTM) that the analyzer
this guide is applicable only to the material type and property
system is intended to emulate, using the principles and ap-
range of the materials representative of those used to perform
proaches outlined in relevant ASTM standard practices and
the assessment. Users are cautioned against extrapolation of
guides.
the relationship beyond the material type and property range
1.2 This guide describes how the statistical methodology of
being studied.
Practice D6708 can be employed to assess agreement between
1.3 This guide applies if the process stream analyzer system
the PTM and analyzer results, and, if necessary, develop linear
and the primary test method are based on the same measure-
correlation to further improve the agreement over the complete
ment principle(s), or, if the process stream analyzer system
usesadirectandwell-understoodmeasurementprinciplethatis
similar to the measurement principle of the primary test
1
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum
method. If the process stream analyzer system uses a different
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
mittee D02.25 on Performance Assessment and Validation of Process Stream
measurement technology from the primary test method, pro-
Analyzer Systems.
vided that the calibration protocol for the direct output of the
Current edition approved Dec. 1, 2021. Published December 2021. Originally
analyzer does not require use of the PTM, this practice also
approved in 2005. Last previous edition approved in 2021 as D7235 – 21. DOI:
10.1520/D7235-21A. applies.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7235 −
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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: D7235 − 21 D7235 − 21a
Standard Guide for
Establishing a Linear Correlation Relationship Between
Analyzer and Primary Test Method Results Using Relevant
1
ASTM Standard Practices
This standard is issued under the fixed designation D7235; 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.
INTRODUCTION
Operation of a process stream analyzer system typically involves four sequential activities:
(1)Analyzer Calibration—When an analyzer is initially installed, or after major maintenance has been
performed, diagnostic testing will typically be performed to demonstrate that the analyzer meets
manufacturer’s specifications and historical performance standards. These diagnostic tests may require
that the analyzer be adjusted so as to provide predetermined output levels for certain reference
materials. (2)Correlation to Primary Test Method—For process stream analyzer systems where the
application objective is to provide prediction of results from a Primary Test method, once the
diagnostic testing is completed, process stream samples will typically be analyzed using both the
analyzer system and the corresponding primary test method. A mathematical function will be derived
that relates the analyzer output to the primary test method (PTM). The application of this mathematical
function to an analyzer output produces a predicted PTM result. (3)Initial Validation—Once the
relationship between the analyzer output and primary test method results has been established, an
initial validation is performed using an independent data set to demonstrate that the predicted PTM
results agree with those from the primary test method within the tolerances established from the
Correlation activities and with no statistically observable systemic bias. (4)Continual Validation—
During normal operation of the process analyzer system, quality assurance testing is conducted to
demonstrate that the agreement between analyzer and primary test method results during the Initial
Validation is maintained. This document provides guidance for item (2) above.
1. Scope*
1.1 This guide covers a general methodology to develop and assess the linear relationship between results produced by a total
analyzer system versus the results produced by the corresponding primary test method (PTM) that the analyzer system is intended
to emulate, using the principles and approaches outlined in relevant ASTM standard practices and guides.
1.2 This guide describes how the statistical methodology of Practice D6708 can be employed to assess agreement between the
PTM and analyzer results, and, if necessary, develop linear correlation to further improve the agreement over the complete
operating range of the analyzer. For instances where there is insufficient variation in property level to apply the Practice D6708
multi-level methodology, users are referred to Practice D3764 to perform a level specific bias evaluation. The correlation
relationship information obtained in the application of this guide is applicable only to the material type and property range of the
1
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.25 on Performance Assessment and Validation of Process Stream Analyzer Systems.
Current edition approved July 1, 2021Dec. 1, 2021. Published July 2021December 2021. Originally approved in 2005. Last previous edition approved in 20162021 as
D7235 – 16.D7235 – 21. DOI: 10.1520/D7235-21.10.1520/D7235-21A.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7235 − 21a
materials representative of those used to perform the assessment. Users are cautioned against extrapolation of the relationship
beyond the material type and property range being studied.
1.3 This guide applies if the process stream analyzer system and the primary test method are based on the same measurement
principle(s), or, if the process stream analyzer system uses a direct and well-understood measurement principle that is similar to
the measurement principle of the primary test method. If the process stream anal
...
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