ISO Class is a designation from the ISO 14644-1 standard that specifies the maximum concentration of airborne particles of specific sizes within a cleanroom. This international standard provides a uniform classification system used globally in regulated industries. ISO Classes range from 1 (cleanest) to 9 (least clean).
Technical Details
ISO Class ratings are determined by counting particles 0.1 micrometers and larger using optical particle counters. The formula Cn = 10^N × (0.1/D)^2.08 calculates maximum particle concentration, where N is the ISO Class number and D is particle size in micrometers. Each class represents a factor of 10 difference in particle concentration from the next class.
Applications
Pharmaceutical manufacturing facilities use ISO Class 5 for aseptic processing. Electronics and semiconductor manufacturing typically use ISO Class 6 or 7. Medical device assembly uses ISO Class 7 or 8 depending on product criticality.
Practical Significance
ISO Class requirements directly drive HVAC specifications, including air change rates, filter types, and system redundancy. Meeting classification requires continuous monitoring and documentation for regulatory compliance in pharmaceutical and medical device sectors.