A common assumption in cleanroom design is that more air changes means a cleaner area. That is not how classification works. ISO 14644 part 1 defines cleanroom classes from ISO 1 to ISO 9 based on the maximum allowable concentration of airborne particles per cubic metre at specific particle sizes. The air change rate is an engineering input used to achieve and maintain that concentration. The air changes create the conditions, and the particle count confirms whether those conditions are sufficient. Read more [Picture source: ABN Cleanroom Technology NV on linkedin.com]
