A Computational Fluid Dynamics (CFD), commercial program was used to assist in the design of a Class I cleanroom, Two cases were studied. The first case included the design of a modular plenum system. The impact of the size of each plenum module on the modular plenum system
performance was studied. A 33-percent less pressure drop was achieved when a regularly designed module; plenum system was carefully redesigned, The second case studied the impact of tool geometry and location on the flow patterns and contamination control in a classroom on. A platform was placed in the cleanroom, and flow simulations by the CFD program were performed. Flow laminarity in the cleanroom was investigated for two designs. These are primarily the same except that one has the platform located so it is in direct contact with the cleanroom wall. It was observed that the design with a gap between the platform and the cleanroom wall significantly reduced the air turbulence above the platform compared with the design with no gap. A platform made of 55-percent perforated plates was shown to be highly efficient in reducing the air turbulence both above and below the platform in both designs.