ForewordIntroductionScopeNormative referencesTerms and definitionsQuantitiesMeter designThermodynamic conditionsStatisticsCalibrationSymbols and subscriptsAbbreviated termsPrinciples of measurementDescriptionVolume flowGeneric descriptionGeneralTransducersMeter body and ultrasonic path configurationsTime measurementTime delay considerationsRefraction considerationsReynolds numberTemperature and pressure correctionPerformance requirementsUncertainty in measurementIntroductionEvaluation of the uncertainty componentsIntroductionUncertainty in the calibration factor (see )Uncertainty () in velocity profile (see )Uncertainty () in the cross-sectional area of the measurement sectionUncertainty () in the path geometry factorUncertainty () in the time measurementUncertainty () in the delay time compensationInstallationGeneralUse of a proverCalibration in a laboratory or use of a theoretical prediction procedureGeneralUpstream and downstream straight pipe length requirementsProtrusions and diameter stepsThermowellsFlow conditionersWall roughnessAdditional installation effectsNon-steady flowContamination by particles, a second liquid or gasVibrationElectrical noiseInsulationAcoustic couplantTest and calibrationGeneralIndividual testing — Use of a theoretical prediction procedureGeometrical parametersTiming and time delays, and zero flow verification testIndividual testing — Flow calibration under flowing conditionsGeneralLaboratory flow calibrationGeneralDuration of the calibrationUncertainty of the calibration facilityFlow conditionsLimited calibration range at initial calibrationBi-directional calibrationReportPerformance testingIntroductionRepeatability and reproducibilityAdditional test for meters with externally mounted transducersAssessing the uncertainty of a meter whose performance is predicted using a theoretical prediction procedureFluid-mechanical installation conditionsPath failure simulation and exchange of componentsMeter characteristicsMeter body, materials, and constructionMaterials and manufactureUltrasonic portsAnti-roll provisionFlow conditionerMarkingsCorrosion protectionTransducersGeneralMarkingCableElectronicsGeneral requirementsPower supplyPulsating flowCable jackets and insulationMarkingSoftwareFirmwareDiscontinuityMarking and version managementInspection and verification functionsInput for diagnosticsExchange of componentsDetermination of density and temperatureDensityTemperature measurementOperational practiceGeneralAudit processOperational diagnosticsSpeed of soundGeneralAbsolute speed-of-sound comparisonRelative speed-of-sound comparison; footprintVelocity ratiosOther parametersAudit trail during operation; inter-comparison and inspectionInter-comparison checks (with multiple meters in series)InspectionsGeneralZero-flow checksVisual InspectionRecalibrationGeneralRecalibration intervalField recalibrationGeneralProversAs-found laboratory recalibrationGeneralHandling in the fieldHandling in the laboratoryTemperature and pressure correctionTemperature correctionPressure correctionGeneralGeneral 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 constraintImpact of temperature and pressure effects on the transducer portsTotal effect of temperature and pressureDetailed calculation procedureEffect of a change of roughnessExample of uncertainty calculationsUncertainty calculation for a calibrated non-refracting chordal multipath meterMathematical modelResults from performance testsInstallation conditionsEvaluation of the contributory variancesGeneralUncertainties of the calibration factor (), the cross-sectional area () and the geometry factor ()Uncertainty in the velocity profile, ()Uncertainty of the time differences, ()Uncertainties of the transit time measurement system () and the delay time ()Combined standard uncertaintyUncertainty calculation for a meter with externally mounted transducersMathematical modelResults from performance testsInstallation conditionsEvaluation of the contributory variancesGeneralUncertainty in the velocity profile, ()Uncertainty of the cross-sectional area, ()Uncertainty of the geometry factor, ()Uncertainty of the time difference, ()Uncertainty of the delay time, ()Uncertainty of the transit time measurement system, ()Combined standard uncertaintyDocumentsGeneralAfter receipt of orderBefore shipment