Clean Rooms - ISO Standard 14644

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

C_n = 10^N (0.1 / D)^2.08         (1)
where
C_n = 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

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