GB/T 18604-2001 in English

《GB/T 18604-2001用气体超声流量计测量天然气流量》由515（中国石油天然气集团公司）归口，主管部门为中国石油天然气集团公司。
本标准适用于传播时间差法气体超声流量计，其通径大于或等于100mm，压力不低于0.1MPa（表压）。一般用于气质符合本标准第5.1条款规定的生产装置、输气管线、储藏设备、配气系统和用户计量系统中的天然气流量测量。本标准使用的天然气体积计算标准参比条件为0.101 325MPa（绝压），温度为20℃（293.15K）。也可采用合同规定的其他参比条件。

Scope

This standard applies to gas ultrasonic flowmeters using the propagation time difference method, with a diameter equal to or greater than 100 mm and a pressure not lower than 0.1 Mpa (gauge pressure). It is generally used for natural gas flow measurement in production equipment, gas transmission pipelines, storage facilities, gas distribution systems and user metering systems whose temperament meets the provisions of Article 5.1 of this standard. The standard reference conditions for natural gas volume calculation used in this standard are: the pressure is 0.101325 Mpa (absolute pressure), and the temperature is 20°C (293.15 K). Other reference conditions stipulated in the contract may also be adopted.