Both Underfloor Air Distribution (UFAD) and Displacement Air Distribution are well defined in the 2021ASHRAE Handbook Applications, Chapter 20, Space Air Diffusion. Generally, the idea for UFAD is to have a well-mixed lower level in the occupied space up to about 4.5 feet above the floor. From the thermocline at 4.5 feet to about 3 to 5 inches from the ceiling is a stratified space. Above the Stratified space, the upper region is the warmest and most polluted air in the room. It is being induced into the return air space or ducts at the ceiling and...
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Nailor Airwaves Archive
Post date: April 25, 2022
Area Source
When a room has a full ceiling stretching from wall to wall, the ceiling isolates the room from the area above the ceiling. Frequently that space above the ceiling is used for the return air path to the air handler. It is also used to mount mechanical equipment, plumbing, electric supplies and lighting. The open space is a separate space from the occupied area below. As such, sound that is generated in the return plenum spreads throughout the plenum and produces an area sound source that emanates across the entire ceiling somewhat...