Cleanroom Classifications

Discover the different classes within the cleanroom ISO standards and their Federal Standard and GMP equivalent. These tables detail the particle counts that define each class. 

Do you need a cleanroom?

Tell us about your project

ISO 14644-1:2015 Cleanroom Classification

ISO 14644 is the international standard for cleanrooms and associated controlled environments. Part 1 details the classification of air cleanliness by particle concentration. 

This table details the air cleanliness classes by particle concentration within ISO 14644-1.

ISO Classification Number	Maximum allowable concentrations (particles/m3) for particles equal to and greater than the considered sizes, shown below
	≥0.1µm	≥0.2µm	≥0.3µm	≥0.5µm	≥1µm	≥5.0µm
ISO Class 1	10b	d	d	d	d	e
ISO Class 2	100	24b	10b	d	d	e
ISO Class 3	1,000	237	102	35b	d	e
ISO Class 4	10,000	2,370	1,020	352	83b	e
ISO Class 5	100,000	23,700	10,200	3,520	832	d,e,f
ISO Class 6	1,000,000	237,000	102,000	35,200	8,320	293
ISO Class 7	c	c	c	352,000	83,200	2,930
ISO Class 8	c	c	c	3,520,000	832,000	29,300
ISO Class 9g	c	c	c	35,200,000	8,320,000	293,000

^a All concentrations in the table are cumulative, e.g. for ISO Class 5, the 10,200 particles shown at 0.3µm include all particles equal to and greater than this size. 
^b These concentrations will lead to air sample volumes for classification. Sequential sampling procedure may be applied.
^c Concentration limits are not applicable in this region of the table due to very high particle concentration.
^d Sampling and statistical limitations for particles in low concentrations make classification inappropriate.
^e Sample collection limitations for both particles in low concentrations and sizes greater than 1µm make classification at this particle size inappropriate, due to potential losses in the sampling system.
^f In order to specify at this particle size in association with ISO Class 5, the macroparticle descriptor M may be adapted and used in conjunction with at least one other particle size.
^g This class is only applicable for the in-operation state.

Maximum permitted total particle concentration for classification by GMP grade

GMP Annex 1 details the maximum permitted particle concentrations for classification, for 'at rest' and 'in operation' states. 

Clean room and clean air device classification, in relation to GMP Annex 1 (2015).

Grade	Maximum limits for total particle ≥0.5µm/m³		Maximum limits for total particle ≥5.0µm/m³
	At rest	In operation	At rest	In operation
A	3,520	3,520	Not specifieda	Not specifieda
B	3,520	352,000	Not specifieda	2,930
C	352,000	3,520,000	2,930	29,300
D	3,520,000	Not predeterminedb	29,300	Not predeterminedb

^a Classification including 5µm particles may be considered where indicated by the CCS or historical trends.
^b For grade D, in operation limits are not predetermined. The manufacturer should establish in operation limits based on a risk assessment and routine data where applicable.

Comparison of Cleanroom Classifications

The 'at rest' limits for GMP, correspond with the limits for ISO classes. 

This table below shows the ISO classes with the equivalent GMP grades. It also details the equivalent Federal Standard class.

Cleanroom Standard	Cleanroom Classification Guidelines
ISO 14644-1	Class 3	Class 4	Class 5	Class 6	Class 7	Class 8
EU GMP (at rest)	-	-	A/B	-	C	D
Federal Standard 209E (replaced in 2001)	1	-10	100	1,000	10,000	100,000

The Federal Standard class was replaced by ISO 14644 in 2001.

  

Talk to the experts at Connect 2 Cleanrooms about your next project

Our cleanroom design and build specialists have experience working with customers in all kinds of industries, achieving great results time and time again. We’d love to work with you as well!

More about our cleanrooms  GMP Cleanrooms

Tell us about your project