Clean rooms are used for experimental studies of a wide variety. Testing and analysis laboratories, used in the medical, military, and processing industries, are all designed to operate as clean rooms. The optimization of clean rooms, therefore, is an important subject to many industries. Therefore, the primary goal of optimization is to maximize plant productivity continuously through the accurate control of parameters. The second goal is to conserve energy. This chapter describes the main control elements and control loop configurations required for arriving at a high-productivity semiconductor manufacturing plant. Plant productivity is maximized if drafts are eliminated in the clean work aisle. Drafts would stir up the dust in this area, which in turn would settle on the product and cause production losses. An added measure of safety is provided by exhausting the air at high velocity, so as to obtain good dispersion in the atmosphere.