ForewordIntroductionScopeNormative referencesTerms, definitions and symbolsTerms and definitionsQuantitiesMeter designThermodynamic conditionsStatisticsSymbols and subscriptsAbbrevationsPrinciples of measurementBasic formulaeFactors affecting the performanceDescription of generic typesGeneralTransducersMeter body and acoustic path configurationsGeneralBasic acoustic paths typesCommonly used multi-path cross-sectional configurationsAverage velocity calculationContributions to the uncertainty in measurementReynolds numberUSM classificationMeter characteristicsOperating conditionsFlow rates and gas velocitiesPressureTemperatureGas qualityMeter body, materials, and constructionMaterialsMeter bodyConnectionsDimensionsGeneralGeometrical parameters of the measuring sectionUltrasonic transducer portsPressure tappingsAnti-roll provisionFlow conditionerMarkingsCorrosion protectionTransducersSpecificationRate of pressure changeTransducer characterizationPath configurationMarkingCableRobustnessElectronicsGeneral requirementsDisplayPower supplySignal detection methodSampling or pulsating flowSignal-to-noise ratioAlarm signalProcessing of dataOutputCable jackets and insulationMarkingSoftwareFirmwareMODBUS communication data specificationDiscontinuityMarking and version managementMonitoring and recording of measuring and diagnostic dataCorrection functions and parametersInspection and verification functionsExchange of componentsSecondary measurementsGeneralPressure measurementTemperature measurementPerformance requirementsGeneralAccuracy requirementsInfluence of pressure, temperature, and gas compositionOperation and installation requirementsGeneralOperational requirementsSound, noise, and pressure-regulating valvesContaminationAmbient temperatureVibrationElectrical noiseNon-steady flowInstallation requirementsGeneralDistance to perturbations, upstream and downstream straight pipe length requirementsProtrusions and diameter stepThermowells and density cellsFlow conditionersInternal surface and wall roughnessBidirectional useOrientation of meterManual handling and transportationDocumentationGeneralGeneric meter documentationParticular meter documentationTest and calibrationPressure testing and leakage testingIndividual testing — Static testingGeneralTiming and time delaysZero flow verification testIndividual testing — Flow calibrationGeneralLaboratory flow calibrationGeneralDuration of the calibrationUncertainty of the calibration facilityFlow conditionsThermal stratification at a calibration facilityBidirectional calibrationJudging the measurement performance of the meterAdjustment and recordsGeneralResultsMeter identification and description of the facilityConditions of the testType testingGeneralAccuracyInstallation conditionsPath failure simulation and exchange of componentsElectronics design testingAudit trail and diagnostics for meter verificationGeneralUSM Lifecycle ProcessProduction and Factory Acceptance TestInitial Flow CalibrationSite installation and site acceptance testOperationDiagnostic warning and alarm levels in operationMSOS and MSOS ratios warning & alarm levelsVelocity ratios warning & alarm levelsS/N ratios warning & alarm levelsService and recalibrationGeneralService Related DiagnosticsDiagnostic parametersSpeed of soundMeasured speed of sound (MSOS)Theoretical speed of sound (TSOS)Automatic gain controlSignal-to-noise ratio (S/N)Acoustic signal acceptanceFlow profileStandard deviation/turbulenceOperational practiceTemperature and pressure correctionCorrection for the temperatureCorrection for the pressureGeneralGeneral simplified expression for any body typeRefinement in initial estimate to account for different meter body designsRefinement in initial estimate for effects of end loading and end support or constraintEffects of transducer portsTotal metering errorDetailed calculation procedureRegistration of error bandsGeneralDerivation and correction of USM errorsMethods for correcting flow measurement error of a USMCalculation of flow-weighted mean error (FWME)GeneralExample of a flow-weighted mean error calculationValve characterization and noise in a metering and regulating stationIntroductionCalculation methodGeneralGeneration of noise by the control valvePractical determination of the valve weighting factor Theoretical determination of the valve weighting factor Propagation of noise from the valve to the USM using attenuation factor, Signal strength of the USM, Signal-to-noise ratio at the USMM&R station designThe calibration time of ultrasonic flow metersIntroductionComparing turbine meters and ultrasonic metersThe minimum calibration timeDetermining the value of Detailed calculation of geometry-related temperature and pressure correctionsGeneral backgroundDirect calculationStep 1 — Body temperature effectStep 2 — Body pressure expansionStep 3 — Correction for body style effect or proximity to flangesStep 4 — Combined pressure correction effectStep 5 — Expansion effects in the transducer portsGeneralPort temperature correctionPort pressure correctionCombined port correctionStep 6 — Combined flow correctionGuidance on the use of finite element modelsGeneralNote on intentional use of thin-wall equations beyond their normal limitCalculation of an initial estimate for the body pressure effectWorked exampleMeter detailsInitial flow error estimateCommon elements to detailed calculationDirect single stage detailed calculationThree stage detailed calculationStage 1 — Static calibration to dynamic calibrationStage 2 — Static calibration to field operationStage 3 — Dynamic calibration to field operation flow correction factorObservations on the example calculationGeneralInitial body pressure estimateMeter end-loading conditionsBody pressure effectBody temperature effectsPort effectsComparison against the results of an FE modelConclusionMODBUS communication data specificationGeneralExampleDisturbance tests