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Cleanroom Standards

ISO Cleanroom Classification

Cleanrooms are classified by cleanliness, measured by the number and size of particulates in the air. The International Standards Organization (ISO) has established a classification system specifically for cleanroom environments. The ISO 14644-1 cleanroom standards are composed of nine classifications for cleanrooms based on the maximum number and size of particulates that exist per cubic meter. A Class 1 designation indicates the highest level of cleanliness with the least number of particulates, while Class 9 indicates the lowest level of cleanliness with the maximum number of particles in the air. For more detailed information, see the chart below.

ISO 14644-1:2015 Cleanroom Standard – This chart details for each classification the maximum number of particles in micrometers (µm) permitted per cubic meter of air.

Class Maximum Particles per m3
≥0.1 μm ≥0.2 μm ≥0.3 μm ≥0.5 μm ≥1 μm ≥5 μm
ISO 1 10 2
ISO 2 100 24 10 4
ISO 3 1,000 237 102 35 8
ISO 4 10,000 2,370 1,020 352 83
ISO 5 100,000 23,700 10,200 3,520 832 29
ISO 6 1,000,000 237,000 102,000 35,200 83,200 2,930
ISO 7 352,000 832,000 2,930
ISO 8 3,520,000 832,000 29,300
ISO 9 35,200,000 8,320,000 293,000

Different industries require different standards of cleanliness in their cleanrooms. We work with you to ensure your space meets the requirements for your specific application.

STERIS offers modular cleanrooms, cleanroom certification and biodecontamination services to help you achieve the cleanroom classification you require.

Cleanroom Services

Certification, testing and decontamination services are part of our Controlled Environment Services portfolio. View a complete list of our service offerings.

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HEPA Filters

STERIS provides high-quality filters suitable for any application to support your needs.

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