Last edited 18 Oct 2018

Face velocity

Ventilation ductwork.jpg

Face velocity is the measured air speed at an inlet or outlet of a heating ventilation and air conditioning (HVAC) system.

For example, a fume hood is a ventilated enclosure that is used to safely handle harmful or toxic fumes or vapours. Airflow into a hood is achieved by an exhaust blower which ‘pulls’ air into and through the hood and exhaust system. The resulting ‘pull’ at the opening of the hood is measured as face velocity.

Face velocity is measured in m/s and can be calculated as the volume flow rate (m³/s) divided by the face area (m²).

Airflow velocity meters can be used to measure face veloity.

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