Standards Development

Scope

This document specifies the principle, method and procedure for measuring the gas mass flow of weighing method standard facility flowing to a pipe in a weighing vessel at known time intervals, as well as the method for estimating the uncertainty associated with the measurement.

It is applicable to static weighing method gas flow standard facility (hereinafter referred to as the "facility") for the gas pressure range above 0.3MPa.

Purpose

Gas flow measurement plays a very important role in various industries. It is widely used in energy, metallurgy, environmental protection, aviation, medicine, chemical industry and other industries and research fields, involving the measurement of natural gas, compressed air, carbon dioxide, nitrogen, mixed gas and other types of industrial gases. With the rapid development of the global industry, the demand for gas flow measurement is increasing.

To meet the growing demand, researchers and engineers are constantly developing more precise, reliable, and efficient gas flow measurement technologies. These technologies must not only exhibit high precision and stability but also adapt to complex industrial environments and various types of gases. The ongoing enhancement of gas flow measurement technology is propelling the advancement and development of related industries. To ensure the accuracy and reliability of gas flow measurements, the values must be traced back to base or derived quantities of the International System of Units (SI) through a traceability chain, using legal metrology calibration steps. The gas flow primary standard plays a crucial role in the flow traceability system. The weighing method is one of the primary standards for gas flow rate measurement, allowing for direct tracing of flow values to SI units. Several countries, including China, Russia, the United States, Japan, and South Korea, have established primary gas flow standards using weighing methods and have conducted gas flow value transmission and related research in industries such as natural gas and aviation. However, there is no international standard to regulate the weighing method for gas flow measurement, and since the primary standard is the first step in the traceability chain, even a slight difference can lead to significant discrepancies in gas quantity values between countries.

As the need for frequent international gas trade grows, it is essential to implement the ILAC MRA (International Laboratory Accreditation Cooperation Mutual Recognition Arrangement) to ensure the fairness and justice of trade and to properly safeguard the national interests of trading partners. To achieve this, it is necessary to establish a standard that unifies gas flow measurement using the weighing method, thereby enhancing consistency and accuracy.