In terms of cleanroom standards, which ISO class provides the cleanest environment?

ISO class 4 provides the cleanest environment among the options listed. ISO classifications are a set of standards that define the maximum allowable levels of particulate contamination in a cleanroom environment.

In ISO class 4, the maximum allowable particle count for particles larger than 0.5 micrometers is significantly lower than in the other classes, allowing for an exceptionally clean environment. This is critical in industries where contamination can greatly affect product quality, such as in pharmaceutical manufacturing, where sterile conditions are necessary to prevent compromising the integrity of medications.

ISO class 5, while still maintaining a high standard of cleanliness, allows more particulate matter compared to ISO class 4. Classes 6 and 7 have even higher particle allowances, meaning the environments are less clean when compared to the stricter standards of ISO class 4. Therefore, for settings that require the utmost cleanliness, such as aseptic processing in pharmacies, ISO class 4 is the ideal choice.