› › › FAQs ISO Classifications
What are ISO cleanroom classifications?
ISO cleanroom classifications, defined by ISO 14644-1, specify the maximum allowable concentration of airborne particles per cubic meter of air at specific particle sizes. The ISO Class scale ranges from 1 (cleanest) to 9 (least clean). The Federal Standard 209E equivalent classifications ranged from Class 1 (ISO Class 3) to Class 100,000 (ISO Class 8).
Common ISO classes and their approximate FS 209E equivalents:
Cleanrooms must undergo regular testing to maintain their ratings and ensure ongoing ISO compliance.
What ISO class cleanroom do I need for my application?
ISO class selection depends on the sensitivity of your product or process to airborne particle contamination:
- ISO Class 8 — Class 100,000 — general assembly, packaging, less sensitive manufacturing
- ISO Class 7 — Class 10,000 — medical device assembly, electronics manufacturing
- ISO Class 6 — Class 1,000 — pharmaceutical manufacturing, precision optics
- ISO Class 5 — Class 100 — aseptic pharmaceutical filling, critical semiconductor processes, clean bench work surfaces
- ISO Class 4 and cleaner — advanced semiconductor fabrication, nanotechnology, specialized life sciences
Clean Air Products manufactures cleanrooms from Class 100,000 (ISO 8) to Class 10 (ISO 4). Contact our engineering team for guidance on the right classification for your specific application.
How is ISO cleanroom classification tested and certified?
ISO cleanroom classification is verified through air particle count testing performed by a qualified third-party testing agency using calibrated particle counters. Testing is conducted per ISO 14644-1 and ISO 14644-2 standards, which specify the sampling locations, number of samples, and calculation methods required to certify a room to a specific ISO class. Cleanrooms must undergo regular re-certification testing (typically at least annually) to maintain their ISO rating. Clean Air Products designs
hardwall and
softwall cleanrooms to meet ISO 14644-5:2004 standards and Federal Standard 209E.
What is the difference between ISO 14644 and Federal Standard 209E?
Federal Standard 209E was the US government's cleanroom classification standard, which used particle counts per cubic foot of air. It was officially cancelled in 2001 and replaced by the international ISO 14644 standard, which uses particles per cubic meter. Many industries and customers still reference the older FS 209E designations (Class 100, Class 10,000, Class 100,000) alongside the current ISO equivalents (ISO 5, ISO 7, ISO 8). Clean Air Products' cleanrooms comply with both ISO 14644-5:2004 standards and Federal Standard 209E.
