Takenami et al. (1994)discuss the clean-air distribution system for a super cleanroom in the semiconductor industry.
The major characteristic of this type of system is that large ducts and fans are not used to circulate the air. Instead, clean air is blown out from fan-equipped filters installed on the ceiling. The air then passes through floor grates into the air return space behind the cleanroom walls where it is returned to the chamber behind the ceiling and recirculated by the filter units. The advantage is that since ducts are not used, duct-induced pressure loss is eliminated, making it possible to reduce blowing power costs to less than one-third of conventional levels.