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Particle
Counter
Calculator
Convert optical particle counts to ISO 4406 cleanliness code and NAS 1638 class
Input Parameters
Particles ≥4 µm (per mL)
Particles ≥6 µm (per mL)
Particles ≥14 µm (per mL)
Calculate
Results
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ISO 4406 Code
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NAS 1638 Class
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Cleanliness Level
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Suitable For
Reference
ISO 4406:1999 - 3-number code (≥4µm / ≥6µm / ≥14µm) Each code step = doubling of particle count NAS 1638 still used in some industries