The American Gas Association published Report No. 9, Measurement of Gas by Multipath Ultrasonic Meters 2nd Edition [Ref 1] in April 2007. Report 9 details recommended practice for using multipath gas ultrasonic meters (USMs) in fiscal (custody) measurement applications. This paper reviews some of history behind the development of AGA Report No. 9 (often referred to as AGA 9), key Report contents, which includes information on meter performance requirements, design features, testing procedures, and installation criteria. This paper also discusses changes that will be incorporated in the next revision. Rev3 of AGA TMC Report 9 was published in July of 2017.
Members of the AGA Transmission Measurement Committee (TMC) wrote AGA 9. It started in 1994 with the development of Technical Note M-96-2-3, Ultrasonic Flow Measurement for Natural Gas Applications [Ref 2]. This technical note was a compilation of the technology and discussed how the USMs worked, and is included as Appendix C in the 2007 edition, but it is deleted from the upcoming revision since most of the principles described in it have been adapted to the Report’s text.
After competition of the Technical Note, the AGA TMC began the developing a new Report for custody application of gas USM technology. More than 50 contributors participated in its development, and included participants from the USA, Canada, The Netherlands, and Norway, representing a broad cross-section of measurement personnel in the natural gas industry at the time (circa 1997).