HANDBOOK OF UNCERTAINTY CALCULATIONS - Ultrasonic fiscal gas metering stations
Norwegian regulations relating to fiscal measurement of oil and gas require that the overall measurement uncertainty is documented to be within defined limits. However, the different methods used have given different results. A consistent and standardised method of uncertainty evaluation has been required, so that different measurement systems could be directly and reliably compared.
In 1993 the ISO report “Guide to the expression of uncertainty in measurement” (commonly referred to as the “Guide” or the “GUM”) was published, with a revision in 1995. This report is providing general rules for evaluating and expressing uncertainty in measurement, intended for a broad scope of measurement areas. The GUM was jointly developed by the International Organisation of Standardization (ISO), the International Electrotechnical Commision (IEC), the International Organization of Legal Metrology (OIML) and the International Bureau of Weights and Measurement (BIPM).