cleanroom class

a standard method for characterizing the cleanliness level of a cleanroom, originally developed by the U.S. government and released as the 209 standard. For example, a class 1 cleanroom has less than 1 particle and a class 100 cleanroom has less than 100 particles >0.5µm in size per ft3 of air respectively. Generally speaking a class 1000, class 100, class 10 and class 1, class 0.1 cleanroom will support production down to approximately, 4µms, 1.25µms, 0.7µms, 0.3µms and <0.1µms respectively.