tokens: Bioburden controlled environments shall be equivalent at least to airborne particulate cleanliness class ISO 7 “ in operation ” in conformance with ISO 14644- Part 1 . NOTE 1 This airborne particulate cleanliness class is applicable to cleanrooms or clean zones within cleanrooms . NOTE 2 Achieving the airborne particulate cleanliness class is not necessarily a matter of changes in the cleanroom or clean zone design or HVAC system but can potentially be achieved by applying proper access control , gowning , and procedures .