When UFAD systems are used, the air handling unit (AHU) sends conditioned air through ducts in the underfloor plenum to flow without constraints and barriers to supply outlets. Many small supply outlets, such as floor diffusers, desktop or partition outlets, are placed near occupants in the underfloor system. Underfloor air conditioning (UfAC) makes use of the space beneath a raised access floor for the distribution of air, eliminating most ducting and pipework. Zonal downflow units, or “CAM” generate conditioned air which is delivered into the supply plena.