ASTM D7808-22

Standard Practice for Determining the Site Precision of a Process Stream Analyzer on Process Stream Material

SIGNIFICANCE AND USE
4.1 The analyzer site precision is an estimate of the variability that can be expected in a UAR or a PPTMR produced by an analyzer when applied to the analysis of the same material over an extended time period.  
4.2 For applications where the process analyzer system results are required to agree with results produced from an independent PTM, a mathematical function is derived that relates the UARs to the PPTMRs. The application of this mathematical function to an analyzer result produces a predicted PPTMR. For analyzers where the mathematical function, that is, a correlation, is developed by D7235, the analyzer site precision of the UARs is a required input to the computation.  
4.3 After the correlation relationship between the analyzer results and primary test method results has been established, a probationary validation (see D3764 and D6122) is performed using an independent but limited set of materials that were not part of the correlation activity. This probationary validation is intended to demonstrate that the PPTMRs agree with the PTMRs to within user-specified requirements for the analyzer system application. The analyzer site precision is a required input to the probationary validation procedures.  
4.3.1 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 PTM then validation is done via D3764. Practice D3764 also applies if the process stream analyzer system uses a different measurement technology from the PTM, provided that the calibration protocol for the direct output of the analyzer does not require use of the PTM.  
4.3.2 If the process stream analyzer system utilizes an indirect or mathematically modeled measurement principle such as chemometric or multivariate analysis techniques where PTMRs are required for the development of the che...
SCOPE
1.1 This practice describes a procedure to quantify the site precision of a process analyzer via repetitive measurement of a single process sample over an extended time period. The procedure may be applied to multiple process samples to obtain site precision estimates at different property levels  
1.1.1 The site precision is required for use of the statistical methodology of D6708 in establishing the correlation between analyzer results and primary test method results using Practice D7235.  
1.1.2 The site precision is also required when employing the statistical methodology of D6708 to validate a process analyzer via Practices D3764 or D6122.  
1.2 This practice is not applicable to in-line analyzers where the same quality control sample cannot be repetitively introduced.  
1.3 This practice is meant to be applied to analyzers that measure physical properties or compositions.  
1.4 This practice can be applied to any process analyzer system where the feed stream can be captured and stored in sufficient quantity with no stratification or stability concerns.  
1.4.1 The captured stream sample introduction must be able to meet the process analyzer sample conditioning requirements, feed temperature and inlet pressure.  
1.4.2 This practice is designed for use with samples that are single liquid phase, petroleum products whose vapor pressure, at sampling and sample storage conditions, is less than or equal to 110 kPa (16.0 psi) absolute and whose D86 final boiling point is less than or equal to 400 °C (752 °F).
Note 1: The general procedures described in this practice may be applicable to materials outside this range, including multiphase materials, but such application may involve special sampling and safety considerations which are outside the scope of this practice.  
1.5 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in parentheses are the hi...

General Information

• Status: Published
• Publication Date: 31-Mar-2022
• ICS: 17.120.10 - Flow in closed conduits
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.25 - Performance Assessment and Validation of Process Stream Analyzer Systems

Relations

• Refers: ASTM D6708-24 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-Mar-2024
• Refers: ASTM D86-23ae1 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D6299-23a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Dec-2023
• Refers: ASTM D86-23a - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D6122-23 - Standard Practice for Validation of the Performance of Multivariate Online, At-Line, Field and Laboratory Infrared Spectrophotometer, and Raman Spectrometer Based Analyzer Systems
• Effective Date: 01-Jul-2023
• Refers: ASTM D6122-19b - Standard Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer Based Analyzer Systems
• Effective Date: 01-Jun-2019
• Refers: ASTM D6708-19 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-May-2019
• Refers: ASTM D6122-19a - Standard Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer Based Analyzer Systems
• Effective Date: 01-May-2019
• Refers: ASTM D6122-19 - Standard Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer Based Analyzer Systems
• Effective Date: 01-Jan-2019
• Refers: ASTM D6122-18 - Standard Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer Based Analyzer Systems
• Effective Date: 01-Jul-2018
• Refers: ASTM D6708-18 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-Apr-2018
• Refers: ASTM D6299-17b - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Dec-2017
• Refers: ASTM D6299-17a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Nov-2017
• Refers: ASTM D6299-17 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Jan-2017
• Refers: ASTM D86-16 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Jul-2016

Overview

ASTM D7808-22 is a standard developed by ASTM International, titled "Standard Practice for Determining the Site Precision of a Process Stream Analyzer on Process Stream Material." This standard outlines a systematic procedure for quantifying the site precision of process stream analyzers when measuring properties or compositions in process stream materials over an extended period. Site precision is a crucial measure of the variability or repeatability that can be expected from an analyzer when repeatedly analyzing the same material under consistent conditions.

The standard is widely applied in industries where process analyzers are used for continuous measurement and control, particularly in petroleum refining and chemical processing. By following ASTM D7808-22, operators and quality control personnel can ensure reliable, consistent, and accurate analytical data from process stream analyzers.

Key Topics

• Site Precision Determination

  • Specifies methods for repetitive measurement of a single process sample to quantify the variability in analyzer results.
  • Requires collecting a minimum of 30 valid analyzer results for statistically meaningful site precision measurements.

• Sample Collection and Handling

  • Emphasizes careful collection and storage of representative quality control (QC) samples to avoid sample stratification or instability.
  • QC samples must meet the analyzer's sample conditioning requirements, including appropriate feed temperature and pressure.

• Scope of Applicability

  • Designed for process analyzer systems analyzing physical properties or compositions where the feed stream can be captured and stored safely.
  • Primarily applicable to single liquid-phase petroleum products within specific vapor pressure and boiling point limits.

• Data Analysis and Validation

  • Provides guidance on utilizing site precision in establishing correlations between analyzer results and results from primary test methods (PTMs).
  • Site precision data is also essential for validating analyzer performance using related standards, ensuring agreement within user-specified requirements.

• Quality Control Integration

  • The procedures outlined can be integrated into ongoing quality control programs, allowing for real-time monitoring and assurance of analyzer performance.

Applications

• Process Stream Analyzers in Refining and Chemical Plants

  • Supports performance verification and validation of online and at-line analyzers used for process control and monitoring.
  • Enables quantification of measurement system precision, supporting compliance with internal and regulatory quality requirements.

• Correlation and Validation Protocols

  • Required for generating mathematical correlations between process analyzer outputs and laboratory test results, ensuring data comparability.
  • Used in probationary validation of new or modified analyzer systems, especially when changing technology or measurement principles.

• Ongoing Analyzer Maintenance

  • Facilitates early detection of analyzer drift or faults by routine precision checks using standardized QC samples, improving reliability and uptime.

Related Standards

Operators using ASTM D7808-22 may also reference the following ASTM standards for complementary procedures and quality assurance:

• ASTM D3764 - Validation of Performance of Process Stream Analyzer Systems
• ASTM D6122 - Validation of Multivariate Online and Laboratory Analyzer Systems
• ASTM D6708 - Statistical Assessment and Improvement of Agreement Between Test Methods
• ASTM D7235 - Guide for Establishing Linear Correlations Between Analyzer and PTM Results
• ASTM D6299 - Statistical Quality Assurance and Control Charting Techniques
• ASTM D86 - Test Method for Distillation of Petroleum Products

Practical Value

ASTM D7808-22 provides industry professionals with a comprehensive and consistent methodology for determining the precision of process stream analyzers in operational environments. Implementation of this practice enhances confidence in analytical measurements, supports process optimization, and contributes to maintaining high-quality standards in process industries. By leveraging this standard, organizations can improve product quality, ensure regulatory compliance, and minimize costly process variances.

Keywords: ASTM D7808-22, process stream analyzer, site precision, quality control, petroleum analysis, process measurement verification, analyzer validation, chemical process industry standards

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.
Designation: D7808 − 22
Standard Practice for
Determining the Site Precision of a Process Stream
Analyzer on Process Stream Material
This standard is issued under the fixed designation D7808; 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.
INTRODUCTION
Whenaprocessstreamanalyzerisusedtomonitororcontrolaprocess,theresultsproducedbythe
analyzer are typically used as surrogates for values that would otherwise have been obtained via
analyses of process samples using a Primary Test Method (PTM). Successful application of the
analyzer requires that the Predicted Primary Test Method Result (PPTMR) produced by the analyzer
agreeswiththePrimaryTestMethodResult(PTMR)towithinsomeuserspecifiedaccuracy(biasand
precision). To achieve this goal, it is typically necessary to develop a correlation that relates raw,
UncorrectedAnalyzer Results (UARs) to PTMRs. The correlation and the analyzers performance are
then assessed during the analyzer validation to establish the expected agreement between the PPTMR
and PTMR. In establishing the correlation, and assessing the performance, it is necessary to know the
precision of both the PPTMR and the PTMR. The precision of the PTMRs is typically established
through statistical quality control procedures described in D6299. The precision of the PPTMRs is
established via procedures described herein. The techniques used to determine process analyzer site
precision can also be used for ongoing quality control of the analyzer measurement system.
1. Scope* 1.4 This practice can be applied to any process analyzer
system where the feed stream can be captured and stored in
1.1 This practice describes a procedure to quantify the site
sufficient quantity with no stratification or stability concerns.
precisionofaprocessanalyzerviarepetitivemeasurementofa
1.4.1 Thecapturedstreamsampleintroductionmustbeable
single process sample over an extended time period. The
to meet the process analyzer sample conditioning
proceduremaybeappliedtomultipleprocesssamplestoobtain
requirements, feed temperature and inlet pressure.
site precision estimates at different property levels
1.4.2 This practice is designed for use with samples that are
1.1.1 The site precision is required for use of the statistical
single liquid phase, petroleum products whose vapor pressure,
methodology of D6708 in establishing the correlation between
atsamplingandsamplestorageconditions,islessthanorequal
analyzer results and primary test method results using Practice
to 110kPa (16.0psi) absolute and whose D86 final boiling
D7235.
point is less than or equal to 400°C (752°F).
1.1.2 Thesiteprecisionisalsorequiredwhenemployingthe
NOTE 1—The general procedures described in this practice may be
statisticalmethodologyofD6708tovalidateaprocessanalyzer
applicable to materials outside this range, including multiphase materials,
via Practices D3764 or D6122.
but such application may involve special sampling and safety consider-
ations which are outside the scope of this practice.
1.2 Thispracticeisnotapplicabletoin-lineanalyzerswhere
the same quality control sample cannot be repetitively intro-
1.5 ThevaluesforoperatingconditionsarestatedinSIunits
duced. and are to be regarded as the standard. The values given in
parentheses are the historical inch-pound units for information
1.3 This practice is meant to be applied to analyzers that
only.
measure physical properties or compositions.
1.6 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 appro-
This test method is under the jurisdiction of ASTM Committee D02 on
priate safety, health, and environmental practices and deter-
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.25 on Performance Assessment and Validation of Process
mine the applicability of regulatory limitations prior to use.
Stream Analyzer Systems.
1.7 This international standard was developed in accor-
Current edition approved April 1, 2022. Published June 2022. Originally
dance with internationally recognized principles on standard-
approved in 2012. Last previous edition approved in 2018 as D7808–18. DOI:
10.1520/D7808-22. ization established in the Decision on Principles for the
*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
D7808 − 22
Development of International Standards, Guides and Recom- 3.1.5 site precision conditions, n—conditions under which
mendations issued by the World Trade Organization Technical test results are obtained by one or more operators in a single
Barriers to Trade (TBT) Committee. site location practicing the same test method on a single
measurement system which may comprise multiple
2. Referenced Documents
instruments, using test specimens taken at random from the
same sample of material, over an extended period of time
2.1 ASTM Standards:
spanning at least a 15day interval. D6299
D86Test Method for Distillation of Petroleum Products and
Liquid Fuels at Atmospheric Pressure
3.1.5.1 Discussion—Site precision conditions should in-
D3764PracticeforValidationofthePerformanceofProcess
clude all sources of variation that are typically encountered
Stream Analyzer Systems
during normal, long term operation of the measurement sys-
D6122Practice for Validation of the Performance of Multi-
tem. Thus, all operators who are involved in the routine use of
variate Online, At-Line, Field and Laboratory Infrared
the measurement system should contribute results to the site
Spectrophotometer, and Raman Spectrometer BasedAna-
precision determination. In situations of high usage of a test
lyzer Systems
method where multiple QC results are obtained within a 24h
D6299Practice for Applying Statistical Quality Assurance
period, then only results separated by at least 4h to 8h,
and Control Charting Techniques to Evaluate Analytical
depending on the absence of auto-correlation in the data, the
Measurement System Performance
nature of the test method/instrument, site requirements, or
D6708Practice for StatisticalAssessment and Improvement
regulations, should be used in site precision calculations to
of Expected Agreement Between Two Test Methods that
reflect the longer term variation in the system. D6299
Purport to Measure the Same Property of a Material
3.1.6 process analyzer system, n—see analyzer.
D7235GuideforEstablishingaLinearCorrelationRelation-
3.2 Acronyms:
ship BetweenAnalyzer and Primary Test Method Results
3.2.1 LPG—liquefied petroleum gas
Using Relevant ASTM Standard Practices
D7278GuideforPredictionofAnalyzerSampleSystemLag
3.2.2 PPTMR(s)—predicted primary test method result(s)
Times
3.2.3 PTM—primary test method
3.2.4 PTMR(s)—primary test method result(s)
3. Terminology
3.2.5 QC—quality control
3.1 Definitions:
3.1.1 aliquot, n—portion of sample being tested that is a 3.2.6 UAR(s)—uncorrected analyzer result(s)
representative portion of the whole.
4. Significance and Use
3.1.2 analyzer, n—see analyzer system.
4.1 The analyzer site precision is an estimate of the vari-
3.1.3 analyzer system, n—for equipment used in the analysis
ability that can be expected in a UAR or a PPTMR produced
of liquid petroleum products and fuels, all piping, hardware,
by an analyzer when applied to the analysis of the same
computer,software,instrument,linearcorrelationormultivari-
material over an extended time period.
ate model required to analyze a process or product sample; the
4.2 For applications where the process analyzer system
analyzer system may also be referred to as the analyzer, or the
results are required to agree with results produced from an
total analyzer system.
independent PTM, a mathematical function is derived that
3.1.3.1 Discussion—Online analyzers that utilize extractive
relates the UARs to the PPTMRs. The application of this
samplingincludesampleloop,sampleconditioningsystemand
mathematical function to an analyzer result produces a pre-
excesssamplereturnsystem(seeFig.1inD3764forexample).
dicted PPTMR. For analyzers where the mathematical
Online analyzers that utilize insertion probes include fiber
function, that is, a correlation, is developed by D7235, the
optics and sample probes.
analyzer site precision of the UARs is a required input to the
3.1.3.2 Discussion—At-line, field and laboratory analyzers
computation.
include the instrument and all associated sample introduction
apparatuses.
4.3 After the correlation relationship between the analyzer
results and primary test method results has been established, a
3.1.4 site precision (R'), n—the value below which the
probationary validation (see D3764 and D6122) is performed
absolutedifferencebetweentwoindividualtestresultsobtained
using an independent but limited set of materials that were not
undersiteprecisionconditionsisexpectedtoexceedabout5%
part of the correlation activity. This probationary validation is
of the time (one case in 20 in the long run) in the normal and
intended to demonstrate that the PPTMRs agree with the
correct operation of the method.
PTMRs to within user-specified requirements for the analyzer
3.1.4.1 Discussion—It is defined as 2.77 times σ , the
R’
system application. The analyzer site precision is a required
standard deviation of results obtained under site precision
input to the probationary validation procedures.
conditions. D6299
4.3.1 If the process stream analyzer system and the primary
test method are based on the same measurement principle(s),
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
or, if the process stream analyzer system uses a direct and
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
well-understood measurement principle that is similar to the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. measurement principle of the PTM then validation is done via
D7808 − 22
D3764. Practice D3764 also applies if the process stream 5.1.2.4 Entrained and free water can adversely affect some
analyzersystemusesadifferentmeasurementtechnologyfrom sample vessel materials of construction.
the PTM, provided that the calibration protocol for the direct
NOTE4—SamplevesselusedtostoreQCmaterialsshallbeconstructed
output of the analyzer does not require use of the PTM.
of materials that do not interact with the sample so as to alter measured
4.3.2 If the process stream analyzer system utilizes an
parameter(s) of interest.
indirect or mathematically modeled measurement principle
5.1.3 For applications where the sample being analyzed is
suchaschemometricormultivariateanalysistechniqueswhere
intended to include sediment or water, or both, then the QC
PTMRs are required for the development of the chemometric
sample should also include sediment or water, or both.
or multivariate model, then validation of the analyzer is done
5.1.3.1 For such multiphase QC samples, the sample must
using Practice D6122.
be homogenized prior to introduction into the analyzer.
4.3.3 BoththeD3764andD6122validationpracticesutilize
5.1.3.2 A common application of this type would be the
the statistical methodology of Practice D6708 to conduct the
measurement of sediment or water, or both, in crude and fuel
probationary validation. This methodology requires that the
oil.
site precision for the PTM and the analyzer site precision be
available.
5.1.4 The process analyzer system
...

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: D7808 − 18 D7808 − 22
Standard Practice for
Determining the Site Precision of a Process Stream
Analyzer on Process Stream Material
This standard is issued under the fixed designation D7808; 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
When a process stream analyzer is used to monitor or control a process, the results produced by the
analyzer are typically used as surrogates for values that would otherwise have been obtained via
analyses of process samples using a Primary Test Method (PTM). Successful application of the
analyzer requires that the Predicted Primary Test Method Result (PPTMR) produced by the analyzer
agrees with the Primary Test Method Result (PTMR) to within some user specified accuracy (bias and
precision). To achieve this goal, it is typically necessary to develop a correlation that relates raw,
Uncorrected Analyzer Results (UARs) to PTMRs. The correlation and the analyzers performance are
then assessed during the analyzer validation to establish the expected agreement between the PPTMR
and PTMR. In establishing the correlation, and assessing the performance, it is necessary to know the
precision of both the PPTMR and the PTMR. The precision of the PTMRs is typically established
through statistical quality control procedures described in D6299. The precision of the PPTMRs is
established via procedures described herein. The techniques used to determine process analyzer site
precision can also be used for ongoing quality control of the analyzer measurement system.
1. Scope*
1.1 This practice describes a procedure to quantify the site precision of a process analyzer via repetitive measurement of a single
process sample over an extended time period. The procedure may be applied to multiple process samples to obtain site precision
estimates at different property levels
1.1.1 The site precision is required for use of the statistical methodology of D6708 in establishing the correlation between analyzer
results and primary test method results using Practice D7235.
1.1.2 The site precision is also required when employing the statistical methodology of D6708 to validate a process analyzer via
Practices D3764 or D6122.
1.2 This practice is not applicable to in-line analyzers where the same quality control sample cannot be repetitively introduced.
1.3 This practice is meant to be applied to analyzers that measure physical properties or compositions.
1.4 This practice can be applied to any process analyzer system where the feed stream can be captured and stored in sufficient
quantity with no stratification or stability concerns.
This test method 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, 2018April 1, 2022. Published August 2018June 2022. Originally approved in 2012. Last previous edition approved in 20122018 as
D7808 – 12.D7808 – 18. DOI: 10.1520/D7808-18.10.1520/D7808-22.
*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
D7808 − 22
1.4.1 The captured stream sample introduction must be able to meet the process analyzer sample conditioning requirements, feed
temperature and inlet pressure.
1.4.2 This practice is designed for use with samples that are single liquid phase, petroleum products whose vapor pressure, at
sampling and sample storage conditions, is less than or equal to 110 kPa (16.0 psi) absolute and whose D86 final boiling point is
less than or equal to 400 °C (752 °F).
NOTE 1—The general procedures described in this practice may be applicable to materials outside this range, including multiphase materials, but such
application may involve special sampling and safety considerations which are outside the scope of this practice.
1.5 The values for operating conditions are stated in SI units and are to be regarded as the standard. The values given in
parentheses are the historical inch-pound units for information only.
1.6 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.
1.7 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:
D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
D3764 Practice for Validation of the Performance of Process Stream Analyzer Systems
D6122 Practice for Validation of the Performance of Multivariate Online, At-Line, Field and Laboratory Infrared
Spectrophotometer, and Raman Spectrometer Based Analyzer Systems
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport
to Measure the Same Property of a Material
D7235 Guide for Establishing a Linear Correlation Relationship Between Analyzer and Primary Test Method Results Using
Relevant ASTM Standard Practices
D7278 Guide for Prediction of Analyzer Sample System Lag Times
3. Terminology
3.1 Definitions:
3.1.1 aliquot, n—portion of sample being tested that is a representative portion of the whole.
3.1.2 analyzer, n—see analyzer system.
3.1.3 analyzer, analyzer system, n—for equipment used in the analysis of liquid petroleum products and fuels, all piping, hardware,
computer, software, instrumentation and calibration instrument, linear correlation or multivariate model required to automatically
perform the analysis of analyze a process or product stream.sample; the analyzer system may also be referred to as the analyzer,
or the total analyzer system.
3.1.3.1 Discussion—
Online analyzers that utilize extractive sampling include sample loop, sample conditioning system and excess sample return system
(see Fig. 1 in D3764 for example). Online analyzers that utilize insertion probes include fiber optics and sample probes.
3.1.3.2 Discussion—
At-line, field and laboratory analyzers include the instrument and all associated sample introduction apparatuses. D6122
3.1.4 site precision (R'), n—the value below which the absolute difference between two individual test results obtained under site
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D7808 − 22
precision conditions may be is expected to occur with a probability of 0.95 (95 %). It is defined as 2.77 times the standard deviation
of results obtained under site precision conditions.exceed about 5 % of the time (one case in 20 in the long run) in the normal and
correct operation of the method.
3.1.4.1 Discussion—
It is defined as 2.77 times σ , the standard deviation of results obtained under site precision conditions. D6299
R’
3.1.5 site precision conditions, n—conditions under which test results are obtained by one or more operators in a single site
location practicing the same test method on a single measurement system which may comprise multiple instruments, using test
specimens taken at random from the same sample of material, over an extended period of time spanning at least a 15 day interval.
D6299
3.1.5.1 Discussion—
Site precision conditions should include all sources of variation that are typically encountered during normal, long term operation
of the measurement system. Thus, all operators who are involved in the routine use of the measurement system should contribute
results to the site precision determination. In situations of high usage of a test method where multiple QC results are obtained
within a 24 h period, then only results separated by at least 4 h to 8 h, depending on the absence of auto-correlation in the data,
the nature of the test method/instrument, site requirements, or regulations, should be used in site precision calculations to reflect
the longer term variation in the system. D6299
3.1.6 process analyzer system, n—see analyzer.
3.2 Acronyms:
3.2.1 LPG—liquefied petroleum gas
3.2.2 PPTMR(s)—predicted primary test method result(s)
3.2.3 PTM —PTM—primary test method
3.2.4 PTMR(s)—primary test method result(s)
3.2.5 QC—quality control
3.2.6 UAR(s)—uncorrected analyzer result(s)
4. Significance and Use
4.1 The analyzer site precision is an estimate of the variability that can be expected in a UAR or a PPTMR produced by an
analyzer when applied to the analysis of the same material over an extended time period.
4.2 For applications where the process analyzer system results are required to agree with results produced from an independent
PTM, a mathematical function is derived that relates the UARs to the PPTMRs. The application of this mathematical function to
an analyzer result produces a predicted PPTMR. For analyzers where the mathematical function, that is, a correlation, is developed
by D7235, the analyzer site precision of the UARs is a required input to the computation.
4.3 After the correlation relationship between the analyzer results and primary test method results has been established, a
probationary validation (see D3764 and D6122) is performed using an independent but limited set of materials that were not part
of the correlation activity. This probationary validation is intended to demonstrate that the PPTMRs agree with the PTMRs to
within user-specified requirements for the analyzer system application. The analyzer site precision is a required input to the
probationary validation procedures.
4.3.1 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 PTM then validation is done via D3764. Practice D3764 also applies if the process stream analyzer system uses
a different measurement technology from the PTM, provided that the calibration protocol for the direct output of the analyzer does
not require use of the PTM.
D7808 − 22
4.3.2 If the process stream analyzer system utilizes an indirect or mathematically modeled measurement principle such as
chemometric or multivariate analysis techniques where PTMRs are required for the development of the chemometric or
multivariate model, then validation of the analyzer is done using Practice D6122.
4.3.3 Both the D3764 and D6122 validation practices utilize the statistical methodology of Practice D6708 to conduct the
probationary validation. This methodology requires that the site precision for the PTM and the analyzer site precision be available.
4.4 The procedures described herein also serve as the basis for a process analyzer quality control system. A representative sample
of the QC material is introduced into the analyzer system in a repeatable fashion. Such sample introduction permits capturing the
effect of the analyzer system operating variables on the UAR and PPTMR output signal from the process analyzer. By comparing
the observed analyzer responses to the expected response for the QC sample, the fitness for use of the analyzer system can be
determined.
5. Procedure
5.1 QC Sample Collection—The intent of t
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