Clean Rooms - ISO Standard 14644

Clean room class limits according ISO Standard 14644-1

Clean room maintained virtually free of contaminants, such as dust or bacteria, are used in laboratory work and in the production of precision parts for electronic or aerospace equipment.

In the clean room standard ISO 14644-1 "Classification of Air Cleanliness" the classes are based on the formula

Cn = 10N (0.1 / D)2.08         (1)

where

Cn = maximum permitted number of particles per cubic meter equal to or greater than the specified particle size, rounded to whole number

N = is the ISO class number, which must be a multiple of 0.1 and be 9 or less

D = is the particle size in micrometers

ISO
Class
Maximum Number of Particles in Air
(particles in each cubic meter equal to or greater than the specified size)
Particle size
> 0.1 μm > 0.2 μm > 0.3 μm > 0.5 μm > 1 μm > 5 μm
ISO Class 1 10 2
ISO Class 2 100 24 10

4

ISO Class 3 1000 237 102 35 8
ISO Class 4 10,000 2,370 1,020 352 83
ISO Class 5 100,000 23,700 10,200 3,520 832 29
ISO Class 6 1,000,000 237,000 102,000 35,200 8,320 293
ISO Class 7 352,000 83,200 2930
ISO Class 8 3,520,000 832,000 29,300
ISO Class 9 35,200,000 8,320,000 293,000

clean room particles sizes iso standard diagram

ISO Cleanroom Standards

  • ISO-14644-1 Classification of Air Cleanliness
  • ISO-14644-2 Cleanroom Testing for Compliance
  • ISO-14644-3 Methods for Evaluating & Measuring Cleanrooms & Associated Controlled Environment
  • ISO-14644-4 Cleanroom Design & Construction
  • ISO-14644-5 Cleanroom Operations
  • ISO-14644-6 Terms, Definitions & Units
  • ISO-14644-7 Enhanced Clean Devices
  • ISO-14644-8 Molecular Contamination
  • ISO-14698-1 Biocontamination: Control General Principles
  • ISO-14698-2 Biocontamination: Evaluation & Interpretation of Data
  • ISO-14698-3 Biocontamination: Methodology for Measuring Efficiency of Cleaning Inert Surfaces

Related Topics

  • Ventilation - Systems for ventilation and air handling - air change rates, ducts and pressure drops, charts and diagrams and more

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