Which is a higher cleanroom level, ISO 4 or ISO 5?
ISO 4 is a higher cleanroom level than ISO 5.
In the ISO 14644-1 cleanroom standard, the smaller the number, the higher the cleanliness level.
ISO 4 (Class 10): The number of airborne particles of diameter greater than 352 per cubic meter, a higher cleanliness level than ISO 5.
ISO 5 (Class 100): The number of airborne particles of diameter greater than 3,520 per cubic meter.
In short, ISO 4 has fewer airborne particles and a cleaner environment.
