ASTM D3244-2018 Standard Practice for Utilization of Test Data to Determine Conformance with Specifications.pdf

1、Designation: D3244 16D3244 18 An American National StandardStandard Practice forUtilization of Test Data to Determine Conformance withSpecifications1This standard is issued under the fixed designation D3244; the number immediately following the designation indicates the year oforiginal adoption or,

2、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.INTRODUCTIONThe properties of commercial petroleum products are measured by standardized labo

3、ratory testmethods to assess their conformance to specifications. Two or more measurement results obtained byperforming the same test method for the same property of a specific sample usually will not benumerically identical. Therefore, the test methods generally include a paragraph on the precision

4、 ofresults. This precision (or, a more appropriate term is imprecision) is an expression of the degree ofagreement that can be expected between the aforementioned measurements.Many difficulties that arise in assessing conformance to specifications are due to test imprecision.Because of this, a true

5、value of a property can never be determined exactly; and it is necessary to inferfrom measured values the range within which the “true value” is likely to lie. The main purpose of thispractice is to indicate how test imprecision should be interpreted relative to specification limit values.1. Scope*1

6、.1 This practice covers guidelines and statistical methodologies with which two parties, usually a supplier and a receiver, cancompare and combine independently obtained test results to obtain an Assigned Test Value (ATV) for the purpose of resolving aproduct quality dispute.1.2 This practice define

7、s a technique for comparing an ATV with a specification limit.1.3 This practice applies only to those test methods which specifically state that the repeatability and reproducibility valuesconform to the definitions herein.1.4 The statistical principles and methodology outlined in this practice can

8、also be used to obtain an ATV for specificationconformance decision when multiple results are obtained for the same batch of product within a single laboratory. For thisapplication, site precision (R) as defined in Practice D6299 shall be used in lieu of test method published reproducibility (R).1.5

9、 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade

10、 (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator AdsorptionD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum P

11、roductsD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD6792 Practice for Quality M

12、anagement Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories1 This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of D02.94 onCoordinating Subcommittee on Quality Assurance an

13、d Statistics.Current edition approved June 1, 2016Oct. 1, 2018. Published June 2016October 2018. Originally published as an appendix to the 1968 Annual Book of ASTM Standards,Part 18. Originally approved as a standard in 1974. Last previous edition approved in 20122016 as D3244 12.D3244 16. DOI: 10.

14、1520/D3244-16.10.1520/D3244-18.2 For referencedASTM standards, visit theASTM website, 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.This document is not an ASTM s

15、tandard 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 adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all c

16、ases 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 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D7372 Guide f

17、or Analysis and Interpretation of Proficiency Test Program ResultsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications2.2 ISO Standard:3ISO 4259 Determination and Application of Precision Data in Relation to Methods of Test3. Terminology3.1 Definitions:

18、3.1.1 acceptance limit (AL), na numerical value that defines the point between acceptable and unacceptable quality.3.1.1.1 DiscussionThe AL is not necessarily the specification limit. It is a value that takes into account the specification limit, the test methodprecision, and the desired probability

19、 of product acceptance if the quality is at the specification limit.3.1.2 assigned test value (ATV), nthe average of all results obtained in the several laboratories which are consideredacceptable based on the reproducibility of the test method.3.1.3 determination, nthe process of carrying out the s

20、eries of operations specified in the test method whereby a single valueis obtained.3.1.4 dispute, nwhen there is a question as to product quality conformance to specification because a test value obtained fallsoutside the specification limit(s).3.1.5 operator, na person who normally and regularly ca

21、rries out a particular test.3.1.6 precision, nthe degree of agreement between two or more test results on the same property obtained using the same testmethod on identical test material. In this practice, precision statements are framed in terms of the repeatability and reproducibilityof the test me

22、thod.3.1.7 receiver, nany individual or organization who receives or accepts the product delivered by the supplier.3.1.8 receivers risk, nthe probability of accepting a product that fails to meet the specification.3.1.9 repeatability (a.k.a. Repeatability Limit) (r), nthe quantitative expression off

23、or the random error associated with a singleoperator in a given laboratory obtaining replicate results with the same apparatus under constant operating conditions on identicaltest material within a short period of time. It is defined (the 3.1.9.1) as that difference between two such single results a

24、sindependent results obtained under repeatability conditions that would be exceeded in the long run in only 1 with an approximateprobability of 5 % (one case in 20 in the long run) in the normal and correct operation of the test method (method.3.1.9.3). (Thisis known as the 95 % confidence level.)3.

25、1.9.1 DiscussionThe repeatability and reproducibility values should have been determined according to the methods described in ASTM ResearchReport RR:D02-1007, Manual on Determining Precision data forASTM Methods of Petroleum Products and Lubricants,4 PracticeD6300, or ISO 4259. D63003.1.9.2 Discuss

26、ionNot all standards organizations define repeatability and reproducibility in precisely these same terms, and attention should alwaysbe paid to definitions before comparing precision values quoted.3.1.9.3 DiscussionThis difference is related to the repeatability or the reproducibility standard devi

27、ation but is not the standard deviation.3.1.10 repeatability conditions, nconditions where independent test results are obtained with the same method on identical testitems in the same laboratory by the same operator using the same equipment within short intervals of time. D63003.1.11 reproducibilit

28、y (a.k.a. Reproducibility Limit) (R), na quantitative expression offor the random error associated withoperators working in different laboratories, each obtaining single results on identical test material when applying the same method.It is defined (the 3.1.9.1) as that difference between two such s

29、ingle and independent results as independent results obtained underreproducibility conditions that would be exceeded in the long run in only 1 with an approximate probability of 5 % (one case in20 in the long run) in the normal and correct operation of the test method. See 3.1.9.3. D63003 Available

30、from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.D3244 1823.1.12 reproducibility conditions, nconditions where independent test results are obtained with the same method on identicaltest items in different laboratories with differen

31、t operators using different equipment. D63003.1.13 result, nthe value obtained by following the complete set of instructions of a test method. It may be obtained from asingle determination or several determinations, depending on the instruction of the test method.3.1.14 supplier, nany individual or

32、organization responsible for the quality of a product just before it is taken over by thereceiver.3.1.15 suppliers risk, nthe probability of rejecting a product that meets the specification.3.1.16 test sample, na portion of the product taken at the place where the product is exchanged, that is, wher

33、e theresponsibility for the product quality passes from the supplier to the receiver. In the event that this is not possible, a suitablesampling location should be mutually agreed upon.3.1.17 true value (), nfor practical purposes, the value towards which the average of single results obtained by N

34、laboratoriesusing the same standard test method tends, when N becomes very large. Consequently, this definition of true value is associatedwith the particular test method employed.4. Significance and Use4.1 This practice provides a means whereby the parties to a transaction can resolve potential qua

35、lity disputes over those productproperties which can be tested and expressed numerically.4.1.1 This practice can be used to ensure that such properties are correctly stated on labels or in other descriptions of the product.4.1.2 This practice can be implemented in those cases where a supplier uses a

36、n in-house or a commercial testing laboratory tosample and test a product prior to releasing the product to a shipper (intermediate receiver) and the ultimate receiver also uses anin-house or commercial testing laboratory to sample and test the product upon arrival at the destination. The ATV would

37、still bedetermined according to 8.3.4.2 This practice can assist in the determination of tolerances from specification limits which will ensure that the true value ofa property is sufficiently close to the specification value with a mutually agreed probability so that the product is acceptable to th

38、ereceiver. Such tolerances are bounded by an acceptance limit (AL). If the ATV value determined by applying this practice falls onthe AL or on the acceptable side of the AL, the product can be accepted; otherwise it shall be deemed to have failed the productacceptance requirement established by appl

39、ying this practice.4.3 Application of this practice requires the AL be determined prior to actual commencement of testing. Therefore, the degreeof criticality of the specification, as determined by the Probability ofAcceptance (Pvalue) that is required to calculate the AL, shallhave been mutually ag

40、reed upon between both parties prior to execution of actual product testing.4.3.1 This agreement should include a decision as to whether the ATV is to be determined by the absolute or rounding-offmethod of Practice E29, as therein defined.4.3.1.1 If the rounding-off method is to be used, the number

41、of significant digits to be retained must also be agreed upon.4.3.1.2 These decisions must also be made in the case where only one party is involved, as in the case of a label.4.3.1.3 In the absence of such an agreement, this practice recommends the ATV be rounded in accordance with the rounding-off

42、method in Practice E29 to the number of significant digits that are specified in the governing specification.4.4 This practice is designed to be suitable for reference in contracts governing the transfer of petroleum products and lubricantsfrom a supplier to a receiver.4.5 As a prerequisite for acce

43、ptance for lab test results to be used in this practice, the following conditions shall be satisfied:4.5.1 Site precision (R) as defined in Practice D6299 for the appropriate test method(s) from each lab, as substantiated byin-house quality control programs, for property typical of the product in di

44、spute, should have a TPI 1.2 (see Practice D6792 forTPI explanation), but at a minimum shall be better than the published method reproducibility (R).4.5.2 Each lab shall be able to demonstrate, by way of results from interlaboratory exchange programs, a lack of a systemic biasrelative to exchange av

45、erages for the appropriate test method(s) as per methodology outlined in Guide D7372.4.5.3 In the event that the site precision of laboratories from two parties are statistically different as confirmed by the F-test (seeAnnex A4), then, for the purpose of establishing the ATV, each laboratorys test

46、result shall be inversely weighted in accordancewith laboratorys demonstrated variance.4.6 It is recommended that this practice be conducted under the guidance of a qualified statistician.5. Sampling5.1 Sampling should be carried out as specified in accordance with the referenced test method, contra

47、ct, or specification for thepetroleum product under test, such as Practice D4057, or Practice D4177, or other referenced standards as appropriate. Obtainenough sample to allow for all required determinations to be made by supplier, receiver, and a possible third party.NOTE 1In the event the contract

48、ual or specification-referenced sampling procedure differs from that outlined in the relevant test method, supplier andreceiver need to ensure the correct sampling procedure is used.D3244 1836. Applying Test Method Precision Data to Accept or Reject Test Results6.1 This section describes procedures

49、in which the precision limits of test methods can be used as a decision criterion to acceptor reject test results.6.2 Significance of Repeatability (r):6.2.1 Acceptance of ResultsWhen only two results are obtained under conditions of repeatability and the difference is equalto or less than the repeatability of the method, the operator may report the average of the two results as being applicable to thesample tested.6.2.2 Rejection of ResultsWhen two results are obtained that differ by more than the repeatability of the method, both shouldbe reje