The purpose of the clean room air-conditioning system is to supply airflow in sufficient volume and cleanliness to support the cleanliness rating of the room. Air is introduced into the clean room in a manner to prevent stagnant areas where particles could accumulate. The air must also be conditioned to meet the clean-room temperature and humidity requirements. In addition, enough conditioned makeup air must be introduced to maintain the specified positive pressurization.

This article considers clean-room airconditioning system design. To simplify the presentation, clean rooms are divided into three general levels of cleanliness: Stringent, Intermediate, and Less Stringent (Table 1).