Air velocity and volume

By measuring an air velocity, you can see how much air is flowing through an air duct or pipe. If you multiply the air velocity by the area of that duct, you also know what the volume flow rate (also called air flow) is. You can then use the airflow measurement to control a ventilation system. Some measuring instruments can control the ventialtion directly, but the control can also be done using a building management system or PLC.

There are some snags in measuring airflow rates. Namely, some air velocity measurements are affected by temperature and, to a lesser extent, barometric pressure. This does not have to be a problem if the temperature, such as in a utility building, is constant, but for strongly fluctuating temperatures we recommend and air velocity measurement with temperature compensation.