ANSI ASME PTC 19.1-2013 Test Uncertainty.pdf

1、Test UncertaintyPerformance Test CodesAN AMERICAN NATIONAL STANDARDASME PTC 19.1-2013(Revision of ASME PTC 19.1-2005)ASME PTC 19.1-2013(Revision of ASME PTC 19.1-2005)Test UncertaintyPerformance Test CodesAN AMERICAN NATIONAL STANDARDTwo Park Avenue New York, NY 10016 USADate of Issuance: May 30, 20

2、14This Code will be revised when the Society approves the issuance of a new edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of this Code.Interpretations are published on the Committee Web page under go.asme.org/InterpsDatabase.Periodically certain act

3、ions of the ASME PTC Committee may be published as Cases. Cases arepublished on the ASME Web site under the PTC Committee Pages at go.asme.org/PTCcommittee asthey are issued.Errata to codes and standards may be posted on the ASME Web site under the Committee Pages toprovide corrections to incorrectl

4、y published items, or to correct typographical or grammatical errorsin codes and standards. Such errata shall be used on the date posted.The PTC Committee Page can be found at go.asme.org/PTCcommittee. There is an option availableto automatically receive an e-mail notification when errata are posted

5、 to a particular code or standard.This option can be found on the appropriate Committee Page after selecting “Errata” in the “PublicationInformation” section.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredit

6、ed as meeting the criteria for American NationalStandards. The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity to participate. The proposed code or standard was madeavailable for public revie

7、w and comment that provides an opportunity for additional public input from industry, academia,regulatory agencies, and the public-at-large.ASME does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or activity.ASME does not take any position with respect to the validi

8、ty of any patent rights asserted in connection with anyitems mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent, nor assumes any such liability. Users of a code or standard are expresslyadvised t

9、hat determination of the validity of any such patent rights, and the risk of infringement of such rights, isentirely their own responsibility.Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted asgovernment or industry endorsement of this

10、code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies, which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any form,in an electronic r

11、etrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersTwo Park Avenue, New York, NY 10016-5990Copyright 2014 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSNotice . viForeword viiCommi

12、ttee Roster . viiiCorrespondence With the PTC Committee ixSection 1 Introduction . 11-1 General 11-2 Uncertainty Classifications 11-3 Advantages of Using This Code . 11-4 Applications 11-5 Disclaimer 2Section 2 Object and Scope 32-1 Object 32-2 Scope 3Section 3 Nomenclature and Glossary. 43-1 Nomenc

13、lature 43-2 Glossary 4Section 4 Fundamental Concepts 64-1 Assumptions . 64-2 Measurement Error . 64-3 Measurement Uncertainty . 64-4 Pretest and Post-Test Uncertainty Analyses 11Section 5 Defining the Measurement Process 135-1 Overview . 135-2 Selection of the Appropriate “True Value” . 135-3 Identi

14、fication of Error Sources . 135-4 Categorization of Uncertainties 145-5 Comparative Testing 15Section 6 Uncertainty of a Measurement 176-1 Random Standard Uncertainty of the Mean 176-2 Systematic Standard Uncertainty of a Measurement 186-3 Classification of Uncertainty Sources 186-4 Combined Standar

15、d and Expanded Uncertainty of a Measurement . 19Section 7 Uncertainty of a Result . 217-1 Propagation of Measurement Uncertainties Into a Result . 217-2 Sensitivity 217-3 Random Standard Uncertainty of a Result . 227-4 Systematic Standard Uncertainty of a Result . 227-5 Combined Standard Uncertainty

16、 and Expanded Uncertainty of a Result 23Section 8 Additional Uncertainty Considerations . 248-1 Correlated Errors . 248-2 Nonsymmetric Systematic Uncertainty 288-3 Fossilization of Calibrations . 328-4 Spatial Variations . 338-5 Analysis of Redundant Means . 348-6 Regression Uncertainty . 358-7 Simp

17、lified Uncertainty Analysis for Calibrations . 37iiiSection 9 Step-by-Step Calculation Procedure 409-1 General Considerations . 409-2 Calculation Procedure . 40Section 10 Examples 4210-1 Combined Cycle Performance Uncertainty . 4210-2 Taylor Series Propagation for Random Errors That Are NotIndepende

18、nt 5210-3 Flow Measurement Using Pitot Tubes . 5410-4 Post-Test Uncertainty Analysis Example: HRSG High Pressure SteamFlow . 5910-5 Humidity Measurement . 6210-6 Periodic Comparative Testing . 71Section 11 References. 79Section 12 Additional References 81Figures4-2-1 Illustration of Measurement Erro

19、rs 74-2-2 Measurement Error Components 74-3.1-1 Population Distribution . 84-3.3-1 Uncertainty Interval 125-3.1-1 Generic Measurement Calibration Hierarchy . 145-4.3-1 “Within” and “Between” Sources of Data Scatter 168-2.1-1 Gaussian Distribution for Nonsymmetric Systematic Errors 298-2.1-2 Rectangu

20、lar Distribution for Nonsymmetric Systematic Errors . 298-2.1-3 Triangular Distribution for Nonsymmetric Systematic Errors . 298-2.1-4 Triangular Distribution of Temperatures . 318-5-1 Three Cases of Redundant Means . 3410-1.1-1 Train Thermal Performance Test . 4310-3.1-1 Four Circumferential and Te

21、n Radial Traverse Locations . 5510-5.1-1 Schematic of Moisture Absorption and Removal System . 6710-5.3.3-1 Example for Estimating Sensitivity From a Chart 7010-6.1-1 Installed Arrangement 7210-6.1-2 Pump Design Curve With Factory and Field Test Data Shown . 7310-6.1-3 Comparison of Test Results Wit

22、h Independent Control Conditions . 7310-6.2-1 Comparison of Test Results Using the Initial Field Test as the Control 77Tables6-4.1-1 Circulating Water-Bath Temperature Measurements 206-4.1-2 Systematic Standard Uncertainty of Average Circulating Water-BathTemperature Measurement 208-1 Burst Pressure

23、s . 258-2.1-1 Expressions for q for the Gaussian, Rectangular, and TriangularDistributions in Figs. 8-2.1-1 Through 8-2.1-3 298-2.1-2 Systematic Standard Uncertainties, bXH6126ns, for the Gaussian, Rectangular,and Triangular Distributions in Figs. 8-2.1-1 Through 8-2.1-3 . 308-6.4.5-1 Systematic Sta

24、ndard Uncertainty Components for YDetermined FromRegression Equation 379-2-1 Table of Data, Independent Parameters 419-2-2 Summary of Data, Calculated Result 4110-1.6-1 Combined Cycle Net Facility Electrical Output Uncertainty Including theCorrelated Uncertainties 4810-1.6-2 Combined Cycle Net Facil

25、ity Heat Rate Uncertainty Including theCorrelated Uncertainties 4910-1.6-3 Combined Cycle Net Facility Electrical Output Uncertainty Excluding theCorrelated Uncertainties 5010-1.6-4 Combined Cycle Net Facility Heat Rate Uncertainty Excluding theCorrelated Uncertainties 51iv10-2.2-1 Test Pressure Dat

26、a for an Orifice Measuring Flow in a Pipe 5210-2.5-1 Individual Delta Pressure Measurements 5410-3.2-1 Average Values at Each Traverse Circumferential and Radial Location 5610-3.3-1 Standard Deviations at Each Traverse Circumferential and RadialLocation . 5610-3.3-2 Summarized Average Circumferentia

27、l Velocities and Grand AverageVelocity 5610-3.6-1 Random Standard Uncertainty for Both Average CircumferentialVelocities and Grand Average Velocity 5710-3.7.1-1 Systematic Standard Uncertainty for Average Circumferential Velocities 5810-3.7.1-2 Systematic Standard Uncertainty Due to Instrumentation

28、Sources forGrand Average Circumferential Velocities . 5810-3.9-1 Components of Uncertainty in the Grand Average Pipe Velocity 6010-4.3.2-1 Identification of Parameters . 6110-4.3.3-1 Calculated Sensitivities of Each Parameter . 6310-4.4-1 Random Standard Uncertainty Estimated for Each Parameter 6410

29、-4.5-1 Systematic Standard Uncertainty Estimated for Each Parameter 6510-4.5-2 Identified Elemental Uncertainty Components and Values That AreAssumed to Be the Same for Each Parameter 6510-4.5-3 Combined Standard Uncertainty and Expanded Uncertainty of theResult 6610-5.2-1 Measured Values and Statis

30、tical Properties 6810-5.4-1 Estimated Values, Standard Uncertainties, and Calculated Sensitivities . 7010-5.5-1 Standard Uncertainties, Combined Standard Uncertainty, and ExpandedUncertainty of the Result . 7210-6.1-1 Pump Design Data (Tcp 20C) . 7210-6.1-2 Summary of Test Results 7210-6.2-1 Uncerta

31、inty Propagation for Comparison With Independent Control 7610-6.2-2 Summary Uncertainties . 7610-6.2-3 Summary of Results for Each Test . 7610-6.3-1 Uncertainty Propagation for Comparative Uncertainty Analysis 7710-6.3-2 Correlated Terms for Comparative Uncertainty Analysis . 78Nonmandatory Appendic

32、esA Statistical Considerations . 83B Guidelines for Degree of Freedom and Confidence Intervals . 93C Propagation of Uncertainty Through Taylor Series . 95D The Central Limit Theorem . 99E General Regression Uncertainty . 100vNOTICEAll Performance Test Codes must adhere to the requirements of ASME PT

33、C 1, GeneralInstructions. The following information is based on that document and is included here foremphasis and for the convenience of the user of the Code. It is expected that the Code user isfully cognizant of Sections 1 and 3 of ASME PTC 1 and has read them prior to applying thisCode.ASME Perf

34、ormance Test Codes provide test procedures that yield results of the highest levelof accuracy consistent with the best engineering knowledge and practice currently available.They were developed by balanced committees representing all concerned interests and specifyprocedures, instrumentation, equipm

35、ent-operating requirements, calculation methods, and uncer-tainty analysis.When tests are run in accordance with a Code, the test results themselves, without adjustmentfor uncertainty, yield the best available indication of the actual performance of the tested equip-ment. ASME Performance Test Codes

36、 do not specify means to compare those results to contractualguarantees. Therefore, it is recommended that the parties to a commercial test agree before startingthe test and preferably before signing the contract on the method to be used for comparing thetest results to the contractual guarantees. I

37、t is beyond the scope of any Code to determine orinterpret how such comparisons shall be made.viFOREWORDIn March 1979 the Performance Test Codes Supervisory Committee activated the PTC 19.1Committee to revise a 1969 draft of a document entitled PTC 19.1 “General Considerations.” ThePTC 19.1 Committe

38、e proceeded to develop a Performance Test Code Instruments and ApparatusSupplement which was published in 1985 as PTC 19.1-1985, “Measurement Uncertainty,” andwhich was intended, along with its subsequent editions, to provide a means of eventual standard-ization of nomenclature, symbols, and methodo

39、logy of measurement uncertainty in ASMEPerformance Test Codes.Work on the revision of the original 1985 edition began in 1991. The two-fold objective wasto improve the usefulness to the reader regarding clarity, conciseness, and technical treatment ofthe evolving subject matter, as well as harmoniza

40、tion with the ISO “Guide to the Expression ofUncertainty in Measurement.” That revision was published as PTC 19.1-1998, “Test Uncertainty,”the new title reflecting the appropriate orientation of the document.The effort to update the 1998 revision began immediately upon completion of that document.Th

41、e 2005 revision was notable for the following significant departures from the 1998 text:(a) Nomenclature adopted was more consistent with the ISO Guide. Uncertainties remainedconceptualized as “systematic” (estimate of the effects of fixed error not observed in the data),and “random” (estimate of th

42、e limits of the error observed from the scatter of the test data). Bothtypes of uncertainty were defined at the standard-deviation level as “standard uncertainties.”The determination of an uncertainty at some level of confidence was based on the root-sum-square of the systematic and random standard

43、uncertainties multiplied times the appropriateexpansion factor for the desired level of confidence (usually “2” for 95%). This same approachwas used in the 1998 revision but the characterization of uncertainties at the standard-uncertaintylevel (“standard deviation”) was not as explicitly stated. Th

44、e new nomenclature was expectedto render PTC 19.1-2005 and subsequent revisions more acceptable at the international level.(b) There was greater discussion of the determination of systematic uncertainties.(c) Text was added on a simplified approach to determine the uncertainty of straight-lineregres

45、sion.The preparation of this 2013 revision began immediately upon publication of PTC 19.1-2005.The main distinguishing characteristics of this revision compared to its immediate predecessorare the following:O The most significant new feature of this revision is the inclusion of several new examplesi

46、n Section 10; these were presented in a simplified format.O The methodology is given, in subsection 8-1, for including the effects of correlated randomerrors in the uncertainty determination.O Subsection 8-2 on nonsymmetric systematic uncertainty has been updated to include distri-butions other than

47、 Gaussian.O A simplified uncertainty analysis for calibrations is presented in subsection 8-7.O A new Nonmandatory Appendix E is included covering general regression uncertainty. Itis much more comprehensive than the treatment of this subject in the earlier versions of thisCode.ASME PTC 19.1-2013 wa

48、s approved by the PTC Standards Committee on October 15, 2013,and was approved as an American National Standard by the ANSI Board of Standards Reviewon November 26, 2013.viiASME PTC COMMITTEEPerformance Test Codes(The following is the roster of the Committee at the time of approval of this Code.)STA

49、NDARDS COMMITTEE OFFICERSP. G. Albert, ChairJ. W. Milton, Vice ChairJ. H. Karian, SecretarySTANDARDS COMMITTEE PERSONNELP. G. Albert, General Electric Co.R. P. Allen, ConsultantJ. M. Burns, Burns EngineeringW. C. Campbell, True North Consulting, LLCM. J. Dooley, Alstom PowerG. J. Gerber, ConsultantP. M. Gerhart, University of EvansvilleR. E. Henry, Sargent however, they shouldnot contain proprietary names or information.Requests that are not in this format will be rewritten in this format by the Committee priorto being answered, which may inadvertently change the intent of the original