A CFD study was carried out to aid in the design of a Class 1000 cleanroom without raised floors. Two design scenarios were considered:

– Scenario 1: Analysis was carried out based on current fan filter unit (FFU), integrated return air chassis (RAC), and high level return (HLR) system, with current equipment layout.

– Scenario 2: Analysis was carried out with proposed 10 units of standing low level return (LLR) to replace HLR at the critical area of the cleanroom.