1、Designation: D7235 14D7235 16Standard Guide forEstablishing a Linear Correlation Relationship BetweenAnalyzer and Primary Test Method Results Using RelevantASTM Standard Practices1This standard is issued under the fixed designation D7235; the number immediately following the designation indicates th
2、e year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONOperation of a process stream analyzer system typi
3、cally involves four sequential activities:(1)Analyzer CalibrationWhen an analyzer is initially installed, or after major maintenance has beenperformed, diagnostic testing will typically be performed to demonstrate that the analyzer meetsmanufacturers specifications and historical performance standar
4、ds.These diagnostic tests may requirethat the analyzer be adjusted so as to provide predetermined output levels for certain referencematerials. (2)Correlation to Primary Test MethodFor process stream analyzer systems where theapplication objective is to provide prediction of results from a Primary T
5、est method, once thediagnostic testing is completed, process stream samples will typically be analyzed using both theanalyzer system and the corresponding primary test method. A mathematical function will be derivedthat relates the analyzer output to the primary test method (PTM).The application of
6、this mathematicalfunction to an analyzer output produces a predicted PTM result. (3)Initial ValidationOnce therelationship between the analyzer output and primary test method results has been established, aninitial validation is performed using an independent data set to demonstrate that the predict
7、ed PTMresults agree with those from the primary test method within the tolerances established from theCorrelation activities and with no statistically observable systemic bias. (4)Continual ValidationDuring normal operation of the process analyzer system, quality assurance testing is conducted todem
8、onstrate that the agreement between analyzer and primary test method results during the InitialValidation 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
9、 totalanalyzer system versus the results produced by the corresponding primary test method (PTM) that the analyzer system is intendedto emulate, using the principles and approaches outlined in relevant ASTM standard practices and guides.1.2 This guide describes how the statistical methodology of Pra
10、ctice D6708 can be employed to assess agreement between thePTM and analyzer results, and, if necessary, develop linear correlation to further improve the agreement over the completeoperating range of the analyzer. For instances where there is insufficient variation in property level to apply the Pra
11、ctice D6708multi-level methodology, users are referred to Practice D3764 to perform a level specific bias evaluation. The correlationrelationship information obtained in the application of this guide is applicable only to the material type and property range of thematerials representative of those u
12、sed to perform the assessment. Users are cautioned against extrapolation of the relationshipbeyond 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 measurementprinciple(s), or, if the pro
13、cess stream analyzer system uses a direct and well-understood measurement principle that is similar tothe measurement principle of the primary test method. If the process stream analyzer system uses a different measurement1 This guide is under the jurisdiction of ASTM Committee D02 on Petroleum Prod
14、ucts, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.25 on Performance Assessment and Validation of Process Stream Analyzer Systems.Current edition approved Dec. 1, 2014April 1, 2016. Published January 2015April 2016. Originally approved in 2005. Last previous editi
15、on approved in 20102014 asD7235 10.D7235 14. DOI: 10.1520/D7235-14.10.1520/D7235-16.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. Becauseit may not be technically possible to ad
16、equately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright AST
17、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1technology from the primary test method, provided that the calibration protocol for the direct output of the analyzer does notrequire use of the PTM, this practice also applies.1.4 This guide does no
18、t apply if the process stream analyzer system utilizes an indirect or mathematically modeled measurementprinciple such as chemometric or multivariate analysis techniques where results from PTM are required for the chemometric ormultivariate model development. Users should refer to Practices E1655 an
19、d D6122 for detailed correlation and model validationprocedures for these types of analyzer systems.NOTE 1For example, this guide would apply for the comparison of benzene measurements from a mid-infrared process analyzer system based onTest Method D6277 to those obtained using PTM Test Method D3606
20、, a gas chromatography based test method. For each sample, the mid-infraredspectrum is converted into a single analyzer result using methodology (Test Method D6277) that is independent of the primary test method (Test MethodD3606). However, when the same analyzer uses a multivariate model to correla
21、te the measured mid-infrared spectrum to Test Method D3606 referencevalues using the methodology of Practice E1655, this guide does not apply. In this case, the direct output of the analyzer is the spectrum, and theconversion of this multivariate output to an analyzer result require results from the
22、 primary test method.1.5 This guide assumes that the analyzer sampling system is fit for use, and both analyzer and lab systems are in statisticalcontrol during the execution of the required tasks. Procedures for testing for proper function of the analyzer sampling system arebeyond the scope of this
23、 guide. For ascertaining whether the systems are in statistical control, refer to Practice D6299 or othertechnical equivalent documents.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to e
24、stablish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3606 Test Method for Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatog-raphyD3764 Practice fo
25、r Validation of the Performance of Process Stream Analyzer SystemsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method)D6122 Practice for Validation of the Performance of Multivariate Online, At-Line, and Lab
26、oratory Infrared SpectrophotometerBased Analyzer SystemsD6277 Test Method for Determination of Benzene in Spark-Ignition Engine Fuels Using Mid Infrared SpectroscopyD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System Pe
27、rformanceD6624 Practice for Determining a Flow-ProportionedAverage Property Value (FPAPV) for a Collected Batch of Process StreamMaterial Using Stream Analyzer DataD6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purportto Measure the Same
28、 Property of a MaterialD7453 Practice for Sampling of Petroleum Products forAnalysis by Process StreamAnalyzers and for Process StreamAnalyzerSystem ValidationD7808 Practice for Determining the Site Precision of a Process Stream Analyzer on Process Stream MaterialE1655 Practices for Infrared Multiva
29、riate Quantitative Analysis2.2 American Petroleum Institute Document:3API TP-550 Manual on Installation of Refinery Instruments and Control Systems, Part II, Process Stream Analyzers3. Terminology3.1 All of the terminology as defined in Practices D3764, D6122, and D6708 are adopted for this guide.3.
30、2 Definitions of Terms Specific to This Standard:3.2.1 primary test method (PTM), ntest method designated by the user of this guide such that the process analyzer systemresults are estimates or prediction of PTM results that would have been obtained if applied to the same material.3.2.1.1 Discussion
31、It is not the intent of this guide to define a test method. Within the context of the intended application of this practice, a PTM canbe any user-designated test method that the process analyzer system test results are intended to estimate or predict.2 For referencedASTM standards, visit theASTM web
32、site, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American Petroleum Institute (API), 1220 L. St., NW, Washington, DC 20005-4070, http:/www.api
33、.org.D7235 1624. Significance and Use4.1 This guide is intended to be used in conjunction with Practice D3764 (Case 1) and Practice D6122 (Case 2). Methodologyin this guide can be used to determine if a linear correlation can improve the performance of the total analyzer system in termsof its abilit
34、y to predict the results that the PTM would have been if applied to the same material. This methodology, which is basedon the same statistical data treatment as Practice D6708, is use to derive the parameters of the linear relationship and to assess thedegree of improvement.4.2 This guide provides d
35、evelopers or manufacturers of process stream analyzer systems with useful procedures for developingthe capability of newly designed systems for industrial applications that require reliable prediction of measurements of a specificproperty by a primary test method of a flowing component or product.4.
36、3 This guide provides purchasers of process stream analyzer systems with some reliable options for specifying performancerequirements for process stream analyzer systems that are used in applications requiring reliable prediction of measurements of aspecific property by a primary test method of a fl
37、owing component or product.4.4 This guide provides the user of a process stream analyzer system with useful information on the work process forestablishing the PTM prediction relationship and prediction performance.4.5 Prediction (correlation) relationship obtained in the application of this guide i
38、s applicable only to the material type andproperty range of the materials used to perform the study. Selection of the property levels and the compositional characteristicsof the samples must be suitable for the application of the analyzer system. Users are cautioned against extrapolation of thepredi
39、ction 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 articulated in PracticeD6708, which is purely statistical in nature. No attempt is made in assessing the
40、 degree of similarity in the analytical techniquebetween the process analyzer and the PTM; hence, results between the PTM and analyzer unit can be highly correlated, but theirmeasurement principles may be completely different, and may not be the principal cause for correlation. Users are thereforeca
41、utioned that a high degree of correlation between results does not necessarily imply a high degree of similarity in themeasurement principles; nor does it imply a similar degree of agreement can be expected in future measurements. In general, ifsample-specific biases are detected, it suggests that t
42、he measurement principles may be different, and may affect thedegree-of-agreement in future use of the scaling/bias-correction equation. Presence or absence of sample-specific effect can be usedas a measure of the robustness of the correlation equation to sample composition or matrix differences.4.7
43、 Implementation of this guide requires that the process stream analyzer system complies with the following conditions:4.7.1 Meets the principles set forth in PART II Process Stream Analyzers of API TP-550,4.7.2 Meets the suppliers recommendation,4.7.3 Complies with operating conditions specified by
44、the manufacturer,4.7.4 A predicted PTM algorithm has already been established if necessary, and4.7.5 Meets applicable quality assurance, data collection and data telemetry protocols.4.8 After installation or major maintenance, conduct such diagnostic tests as recommended by the manufacturer to demon
45、stratethat the analyzer meets manufacturers specifications, historical performance levels or both. If necessary, adjust the analyzer systemcomponents so as to obtain recommended analyzer output levels for specified reference materials.4.9 Inspect the entire analyzer system to ensure it is installed
46、properly, is in operating condition, and is properly adjusted aftercompletion of the initial commissioning procedures.5. Analyzer Calibration Adjustments and Diagnostics Tests5.1 When an analyzer is initially installed or after major maintenance has been performed, diagnostic tests should be conduct
47、edto demonstrate that the analyzer meets manufacturers specifications and historical performance standards. These diagnostic testsmay require that the analyzer be adjusted so as to provide predetermined output levels for certain reference materials. Suchadjustment may be done in hardware, software o
48、r both. This should not be confused with the development of correlation to a PTM,which, is described below.6. Correlation to Primary Test Method6.1 General Approach:6.1.1 Define the sample set to be used for assessment.6.1.1.1 The material type and property range for which the analyzer system result
49、s are to be assessed versus the primary testmethod is defined.6.1.1.2 The recommended sample set design criteria for this assessment are:(1) A minimum of six replicates at each major product/property level combination,(2) The range of major product/property levels exceed at least two times the published reproducibility of the PTM, and(3) A minimum of 30 total samples.D7235 1636.1.1.3 Replication at a specific level/product combination can be different batches of production material that are nominallysimilar in property level (within 1.2 times the ASTM reproducibili
