This part of GB/T 25915 classifies the air cleanliness level of clean rooms and related controlled environments only based on the concentration of airborne particles in them. The concentration refers to the total number of particles whose particle size is greater than or equal to the threshold (lower limit) The prescribed threshold (lower limit) particle size is 0.1 μm to 5 μm. This part does not establish the cleanliness level of the total number of particles other than the specified particle size of 0.1μm ~ 5μm. But U descriptor and M descriptor can be used to express the total number of ultrafine particles (<0.1μm) and large particles (>5μm) respectively. This section cannot be used to describe the physical, chemical, radioactive or survivable characteristics of airborne particles.
GB/T 25915.1-2010 history
2021GB/T 25915.1-2021 Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness by particle concentration
2011GB/T 25915.1-2010 Cleanrooms and associated controlled environments.Part 1:Classification of air cleanliness