本标准建立了通用术语，并给出了热分散流量计的质量、说明、操作原理、选择、安装和流量校准指南，用于测量封闭管道中流体流量的质量流量，以及在较小程度上测量体积流量。多变量版本可额外测量流体温度。热分散质量流量计适用于已知成分的单相纯气体和气体混合物的流动，不太常见的是，适用于已知成分的单相液体。配套标准ASME MFC-21.1包括毛细管式热质量流量计和控制器。

This Standard establishes common terminology and gives guidelines for the quality, description, principle of operation, selection, installation, and flow calibration of thermal dispersion flowmeters for the measurement of the mass flow rate, and to a lesser extent, the volumetric flow rate, of the flow of a fluid in a closed conduit.Multivariable versions additionally measure fluid temperature. Thermal dispersion mass flowmeters are applicable to the flow of single-phase pure gases and gas mixtures of known composition and, less commonly, to single-phase liquids of known composition. Companion standard ASME MFC-21.1 covers capillary tube type thermal mass flowmeters and controllers.