ISO INTERNATIONAL STANDARD 4124 First edition 1994-12-15 Liquid hydrocarbons Dynamic measurement Statistical control of volumetric metering systems Hydrocarbures liquides - Mesurage dynamique - Controle statistique des systemes de mesurage volumetrique Reference number ISO4124:1994(E) n for Standardizatior Provided by IHS und No reproduction or networking permtted without license from IHS Not for Resale ISO 4124:1994(E) Contents Page Section 1 General 1.1 Scope 1.2 Definitions 1 1.3 Symbols and units 2 1.3.1 General symbols 2 1.3.2 Statistical symbols 2 1.4 Central proving 3 1.5 On-line proving 3 Section 2 Statistical measurements 4 2.1Principles of statistical measurement 4 2.1.1 Introduction 2.1.2 Distribution of measurements 2.1.3 Estimate of true quantity 5 2.1.4 Estimate of standard deviation 5 2.1.5 Estimate of the uncertainty 5 2.1.6 Estimate of repeatability 6 2.1.7 Estimate of maximum range 6 2.1.8 Combination of errors 7 2.2 Measurement procedure 2.2.1 Introduction 7 2.2.2 Statistical control 8 2.2.3 Measurement reliability 8 2.2.4 Performance charts 8 2.2.5 Control charts ISO1994 or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization CasePostale56.CH-1211Geneve20·Switzerland Printed in Switzerland No reproduction or networking permitted without license from IHS Not for Resale ISO ISO4124:1994(E) Section3 Central proving 11 3.1 Collection of data 11 3.1.1 Proving conditions 11 3.1.2 Test report 12 3.2 Reliability of data collected and resulting values 12 3.2.1 Central proving operational conditions 12 3.2.2 Reliability of data collected 12 3.2.3 Resulting values 14 3.2.4 Variation in meter factor with (Q, v) 14 3.3 Performance charts 14 3.3.1 General 14 3.3.2 Preparation of data 14 3.3.3 Meter calibration and performance charts 15 3.4 Control charts and tests 21 3.4.1 Quality of meters 21 3.4.2 Frequency of proving 21 3.4.3 Control charts and tests corresponding to any meter 21 3.4.4 Control charts and tests via polynomials 21 3.4.5 Control charts via direct matrix 24 3.5 Worked examples 24 3.5.1 Scope of examples 24 3.5.2 Example 1: Test for outliers 24 3.5.3 Example 2: Test for repeatability 25 3.5.4 Example 3: Test of the range 26 3.5.5 Example 4: Resulting values 27 3.5.6 Example 5: Preparation of data 28 3.5.7 Example 6: Universal calibration curve (UCC) 30 Section 4 On-line proving 51 4.1 Collection of data 51 4.1.1 Proving conditions 51 4.1.2 Effect of flowrate 52 ili nal Organiza n for Standardizatic No reproduction or networking permited without license from IHS Not for Resale ISO 4124:1994(E) @ ISO 4.2 Reliability of data collected 53 4.2.1 Operating conditions 53 4.2.2 Data analysis 53 4.3 Performance charts 53 4.3.1 General 53 4.3.2 Initial proving data 53 4.3.3 Prior data 54 4.4 Control charts 54 4.4.1 General 54 4.4.2 Use of control charts 56 4.5 Worked examples 59 4.5.1 Scope of examples 59 4.5.2 Example 1 -- Test for outliers 59 4.5.3 Example 2 - Estimation of random uncertainty of K-factor 60 4.5.4 Example 3 Establishing a control chart for a meter operating within its linear range 62 4.5.5 Example 4 -- Establishing a control chart for a meter operating outside its linear range and with varying temperatures 64 4.5.6 Example5 Uncertainty of metered quantity (combined random and systematic uncertainty) 69 Section 5 Secondary control 70 5.1 Comparison between meter and tank 70 5.1.1 General 70 5.1.2 Principle of monitoring system 70 5.1.3 Tank gauging uncertainty 70 5.1.4 Meter uncertainty 71 5.1.5 Caicuiation of uncertainty of transfer 71 5.1.6 Tables of uncertainty 71 Annexes A Statistical tables 75 B t-distribution values for 95 % and 99 % probability (two-sided) 78 C Normal(Gaussian)distribution 79 IV No reproduction or networking permitted without license from IHS Not for Resale CISO ISO 4124:1994(E) D Outlier tests 81 E Random uncertainty of poly