Even if it’s classified as the “dirtiest” class, the ISO 9 clean room environment is cleaner than a regular room.The Iso Zone is the next Rom site to fall! No. ISO 1 is the “cleanest” class and ISO 9 is the “dirtiest” class. Jun 10, 2014This ISO standard includes these clean room classes : ISO 1, ISO 2, ISO 3, ISO 4, ISO 5, ISO 6, ISO 7, ISO 8 and ISO 9.
