Underfloor air distribution (UFAD) is an air distribution strategy for providing ventilation and space conditioning in buildings as part of the design of an HVAC system.

UFAD systems use the underfloor plenum beneath a raised access floor to provide conditioned air through floor diffusers directly to the occupied zone, with the intent of maintaining comfort and indoor air quality levels only in the occupied lower portion of space.

• UFAD Plenum typically at 0.05-0.10 in. wg (12-25 Pa)
• UFAD systems provide ~ 1.0 cfm/ft2 floor area
• Air Leakage affects comfort, energy, safety, security
• Goal is < 10% air leakage at design s.p.