Air velocity (distance traveled per unit of time) is most often expressed in feet per minute (FPM). ... Air velocity is measured by sensing the pressure that is produced through the movement of the air. Velocity is also related to air density with assumed constants of 70° F and 29.92 in Hg.
Pitot Tube Wind Tunnel Anemometer Calibration 0.5-20 m/s. as per IEC-61400-12-1 STANDARD