在建筑物的冷负荷和热负荷中，从外部吸入的空气占整个负荷的很大一部分；为了估算该负荷，有必要正确掌握通风和空调系统的空气流量。本国际标准规定了在稳定运行的通风和空调系统以及空气控制端口（包括空气扩散器、吸入口和排气口）中，测量通过管道的空气流量的方法。

In the cooling and heating loads of a building, the air taken in from outside account for a large portion of the entire load; in order to estimate this load, it is necessary to correctly grasp the air flow rate of ventilation and air-conditioning systems. This International Standard stipulates the methods for measuring the rate of air flow through the ducts in a steadily operating ventilation and air-conditioning system and in the air control ports including air diffuser, suction opening, and exhaust opening.