Purpose: According to the technical specifications of BS EN IEC 60879:2019, GB/T13380-2018, GB 12021.9-2021 “Energy Efficiency Limits and Grades for Electric Fans“: 1 Scope of application (applicable standards) The requirements for this air volume testing device are based on the convenience of walking, and because the testing methods are basically the same, it can meet the air volume testing requirements of table fans, wall fans, floor fans, and column fans Four anemometers are used to collect wind speed (two anemometers are added in the vertical direction on top of the original two horizontal anemometers on the test plane) to represent the average wind speed on the same ring.