Cleanroom Classification: ISO 14644 and FED-STD-209E Conversion
What is Cleanroom Classification?
Cleanrooms are classified by the concentration of airborne suspended particles. The current international standard is ISO 14644-1: an ISO 5 cleanroom allows no more than 10,200 particles ≥ 0.3 μm per cubic meter, corresponding to 209E Class 100 (no more than 100 particles ≥ 0.5 μm per cubic foot). The tool carries the particle size–concentration tables of both standards, and is also useful for re-classifying a remodeled cleanroom and reviewing supplier cleanliness certificates.
When to Use It
Use it for the design and acceptance of semiconductor fabs, pharmaceutical plants, electronics assembly, and medical or food cleanrooms; for comparing routine monitoring data with the class limits; for proving class compliance in customer audits; and when switching between the new ISO standard and legacy 209E specifications. For a new facility it can help set the target class and filter requirements at the design stage, reducing rework and acceptance risk.
How to Use It (Step by Step)
Select the target class or enter measured data, choose the particle size of interest (commonly ≥ 0.5 μm or ≥ 0.3 μm), and the tool computes the concentration limits per ISO 14644-1 plus the 209E equivalent. For measured data, it calculates the 95% upper confidence limit (UCL) per the ISO 14644-1 annex and judges conformance, with the testing state (static or dynamic) noted in the report.
Key Formulas / Example
ISO 14644-1 concentration limit: C_n = 10^N × (0.1/D)^2.08 particles/m³, where N is the ISO class and D the particle size in μm. Example: ISO 5 at D = 0.5 μm gives C_n = 10⁵ × (0.1/0.5)^2.08 ≈ 3,520 particles/m³, equivalent to 209E Class 100.