ISO 12242:2012规定了超声波液体流量计的要求和建议，该流量计利用超声波信号的传输时间测量封闭管道中单相均质液体的流量。 仪表的最小或最大尺寸没有限制。 ISO 12242:2012规定了液体流量测量用超声波流量计（USM）的性能、校准和输出特性，并涉及安装条件。它包括有无专用验证（校准）系统的安装。 它涵盖了串联式和夹持式传感器（用于光束不折射和折射的配置）。包括带有仪表本体的仪表和带有现场安装传感器的仪表。

ISO 12242:2012 specifies requirements and recommendations for ultrasonic liquid flowmeters, which utilize the transit time of ultrasonic signals to measure the flow of single-phase homogenous liquids in closed conduits. There are no limits on the minimum or maximum sizes of the meter. ISO 12242:2012 specifies performance, calibration and output characteristics of ultrasonic meters (USMs) for liquid flow measurement and deals with installation conditions. It covers installation with and without a dedicated proving (calibration) system. It covers both in-line and clamp-on transducers (used in configurations in which the beam is non-refracted and in those in which it is refracted). Included are both meters incorporating meter bodies and meters with field-mounted transducers.