A pocket of stagnant air in a room or building caused by poor diffuser placement, blocked returns, or inadequate fan power. Without proper mixing, these zones suffer from temperature stratification, lingering odors, and poor indoor air quality. Technicians identify these spots using smoke pens or thermal anemometers during a test and balance procedure.
The conference room corner is completely dead air, so we need to adjust the throw on that ceiling diffuser.
Also heard as
- stagnant air
Related terms
Throw
How far a supply air jet reaches into a room before it slows to a chosen speed, such as 50 feet per minute.
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.
Test and balance
Measuring and adjusting a building's air and water flows so every outlet, coil and zone gets its design amount.