ISO 14644-1 classifies cleanrooms by the number of particles 0.5 µm and larger per cubic meter of air. The scale runs from ISO Class 3 (equivalent to the former Federal Standard 209E Class 1) through ISO Class 8 (Class 100,000). For example, ISO Class 5 allows 3,520 particles of 0.5 µm or larger per cubic meter, equivalent to 100 particles per cubic foot (Class 100).
Learn more >>