ISO 17089-1 is a safety standard on ultrasonic meters for gas. It specifies requirements and recommendations for ultrasonic gas flowmeters (USMs), which utilize the transit time of acoustic signals to measure the flow of single-phase homogenous gases in closed conduits.
ISO 17089-1 applies to transit time ultrasonic gas flowmeters used for custody transfer and allocation metering, such as full-bore, reduced-area, high-pressure, and low-pressure meters or any combination of these. There are no limits on the minimum or maximum sizes of the meter. ISO 17089-1 can be applied to the measurement of almost any type of gas, such as air, natural gas, and ethane.
Included are flow measurement performance requirements for meters of two accuracy classes suitable for applications such as custody transfer and allocation measurement. ISO 17089-1 specifies construction, performance, calibration, diagnostics for meter verification, and output characteristics of ultrasonic meters for gas flow measurement and deals with installation conditions.
NOTE: It is possible that national or other regulations apply which can be more stringent than those in ISO 17089-1.
ISO 17089-1 on ultrasonic meters for gas is relevant to:
Ultrasonic meters (USMs) for gas flow measurement have penetrated the market for meters rapidly since 2000 and have become one of the prime flowmeter concepts for operational use as well as custody transfer and allocation measurement. Next to the high repeatability and high accuracy, ultrasonic technology has inherent features like negligible pressure loss; high rangeability; and the capability to handle pulsating flows.
USMs can deliver extended diagnostic information through which it is possible to demonstrate the functionality of a USM. Also, the measured speed of sound of the USM may be compared with the speed of sound calculated from pressure, temperature, and gas composition, to check the mutual consistency of the four instruments involved. Due to the extended diagnostic capabilities, ISO 17089-1 advocates the addition and use of automated diagnostics instead of labor-intensive quality checks. ISO 17089-1 focuses on meters for custody transfer and allocation measurement (class 1 and class 2 meters). USMs are available in a variety of path configurations. The number of measurement paths is generally chosen based on a requirement with respect to variations in velocity distribution and required accuracy.
Overall, ISO 17089-1 is useful as it provides guidance on USMs that are based on the measurement of the propagation time of acoustic signals in a flowing medium. The performance of a USM is dependent on several intrinsic and extrinsic factors.
BS ISO 17089-1:2019 supersedes BS ISO 17089-1:2010, which is withdrawn. BS ISO 17089-1:2019 replaces the first edition (ISO 17089-1:2010), which has been technically revised. The main changes compared to the previous edition are as follows:
ISO 17089-1