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Foreword ii1 Scope 12 Normative references 13 Symbols and abbreviations 24 Selection 35 Installation recommendations 146 Operational considerations 227 Ultrasonic flowmeter verification and calibration 358 Condition-based maintenance (CBM) 53AnnexesAnnex A (informative) Application of flow calibration results 56Annex B (informative) Methods for correcting a USM’s flow measurement errorat flow calibration 59Annex C (informative) Thermowell installations in bi-directional flowinstallations incorporating flow-conditioners 66Bibliography 67List of figuresFigure 1 – General ray geometry for transit time velocity measurement 4Figure 2 – Transducer designs 7Figure 3 – Variations in path configuration 8Figure 4 – Some typical cross-sectional acoustic path configurations 11Figure 5 – Performance specification summary for Class 1 meters 23Figure 6 – Performance specification summary for Class 2 meters 24Figure 7 – Performance specification summary for Class 3 meters 25Figure 8 – Performance specification summary for Class 4 meters 26Figure B.1 – Un-corrected and FWME-corrected flow calibration 62Figure C.1 – Bi-directional flow installation employing two USMs 66Figure C.2 – Bi-directional flow installation employing one USM 66List of tablesTable 1 – Symbols and abbreviations 2Table 2 – Class performance criteria – Meter requirements 12Table 3 – System uncertainties and applications – System requirements 13Table 4 – Common thermal expansion coefficients in the 0 to 100 °C range 27Table 5 – Calibration options and applications 36Table 6 – Internal diameter tolerance 36Table 7 – Tolerance for beam path length 37Table 8 – Minimum nominal test flow rates 43Table 9 – Spread or repeatability (max. error minus min. error) versus number oftest points for a specified uncertainty in the mean 45Table 10 – Effects of number of readings 45Table A.1 – Sequential flow calibration results 58Table B.1 – Example flow calibration data table for 200 mm diameter USM 60Table B.2 – Flow weighted mean error calculation 61Table B.3 – FWME-corrected flow calibration data summary 61Table B.4 – Example results from a typical flow calibration 63Table B.5 – Example calibration results 64Table B.6 – Calculation of percentage flowrate 65