Filtration in a clean room usually centers around the HVAC system. This system should be isolated from thae rest of the plant and utilize HEPA filters.
Special attention should be given to how the air moves around the room and how often it is recirculated. HEPA filters must be able to remove 99.97% of all particles 0.3 micron or bigger in a single pass. If compressed air is used in this area, it must also meet those specifications.
Clean rooms are classified by how many particles are allowed. A class 100 Clean room would have no more than (100) 0.5 micron particles per cubic foot. Go to our section on Air Intake Filters and Air Dryers & Coalescers for more information.