scope:

This International Standard specifies requirements and recommendations for ultrasonic gas flow meters, which utilize the transit time of acoustic signals to measure the flow of single-phase homogenous gases in closed conduits. This International standard is applicable to transit time ultrasonic gas flow meters and is focused towards custody transfer and allocation metering, such as but not limited to full bore, reduced area, high pressure, low pressure meters or any combination of these. There are no limits on the minimum or maximum sizes of the meter. It can be applied to the measurement of almost any type of gas; such as but not limited to air, natural gas, ethane etc. Included are flow measurement performance requirements for meters of two accuracy classes suitable for applications such as custody transfer and allocation measurement. This International Standard specifies construction, performance, calibration and output characteristics of ultrasonic meters for gas flow measurement and deals with installation conditions. In many countries, some or all of the items covered by this International Standard are subject to mandatory regulations imposed by the laws of these countries. In cases where conflict exists between such regulations and this International Standard, the former shall prevail.