Diffuser catalogs list throw to terminal velocities such as 150, 100 and 50 feet per minute. Designers pick outlets whose throw reaches far enough to mix the room without blowing hard on people or slamming into walls. Too little throw leaves dead spots and stratification; too much creates drafts. Throw drops sharply when airflow is turned down, a known problem with VAV systems at low load.
Throw on that slot diffuser is 18 feet, it's hitting the glass wall and dumping on the desks below.
Throw shrinks when a VAV box turns down, so a diffuser that works at full flow can dump cold air at minimum.
Also heard as
- air throw
Related terms
Diffuser
A supply air outlet, usually in the ceiling, that spreads air into the room in a set pattern and mixes it with room air.
Register
A supply or return grille fitted with a damper so its airflow can be adjusted or shut off.
VAV
Variable air volume: a system that holds supply air temperature steady and varies the amount of air to each zone.
CFM
Cubic feet per minute: the standard unit of airflow through equipment, ducts and outlets.