Presented on Tuesday 16 May: Session 2 The accuracy of ultrasonic metering technology has advanced to a level that it is now the technology of choice in many custody transfer and fiscal applications. With meters capable of meeting the accuracy requirements of these applications when initially calibrated, end-user attention has moved to the diagnostic capability of these meters. Diagnostics are now commonly used to increase the confidence of the user that the meter is functioning accurately between calibrations, which could be a year apart or even longer. Although current ultrasonic meter diagnostics are very powerful, they are qualitative in nature, i.e. they provide an indication if something is wrong or has changed, but they have not yet been able to quantify the possible range of error, correctly termed the ‘measurement uncertainty’. This paper presents new technology that has been developed to equip ultrasonic flowmeters with additional measurement data that is used to quantify the uncertainty in the meter’s output. This capability reduces the complexity of diagnostic monitoring, as the result can be monitored as an uncertainty in volumetric or percentage terms, and hence, it allows for quick and simplified decision making. The paper presents the fundamentals of the new self-verifying technology and the testing that has been conducted to validate the uncertainty output provided by the meter. This includes an independent technology qualification evaluation conducted by DNV where the meter was subjected to a variety of real-world upset conditions and the meter performance and uncertainty output were compared with reference data from traceable test facilities. To access the Oral Presentation click the link on the right. To read the full paper click here