Clean-Cell™ Cleanliness & Air Change Rate

Nano Clean Clean-Cell™ Cleanrooms are designed to satisfy the cleanliness requirements of ISO 14644 - Cleanrooms and Associated Controlled Environments.

Cleanroom cleanliness is defined in ISO 14644-1:2015 Classification of Air Cleanliness by Particle Concentration in Table 1 - ISO Classes of Air Cleanliness by Particle Concentration:

ISO Class	Maximum allowable concentration (particles/m3) for particles equal to or greater than the consider sizes
	=>0.1um	=>0.2um	=>0.3um	=>0.5um	=>1.0um	=>5.0um
ISO Class 1	10
ISO Class 2	100	24	10
ISO Class 3	1 000	237	102	35
ISO Class 4	10 000	2 370	1 020	352	83
ISO Class 5	100 000	23 700	10 200	3 520	832
ISO Class 6	1 000 000	237 000	102 000	35 200	8 320	293
ISO Class 7				352 000	83 200	2 930
ISO Class 8				3 520 000	832 000	29 300
ISO Class 9				35 200 000	8 320 000	293 000

Cleanroom occupancy state is defined by ISO 14644-1:2015 Classification of Air Cleanliness by Particle Concentration, as either:

As Built
At Rest
Operational

The below table indicates the variables that practically impact Cleanroom cleanliness:

Variables	As Built	At Rest	Operational
Cleanliness Class	Yes	Yes	Yes
Air Change Rate	Yes	Yes	Yes
Filter Efficiency	Yes	Yes	Yes
Differential Pressure	Yes	Yes	Yes
Process Contamination		Yes	Yes
Personnel Contamination			Yes

When defining the requirements of a Nano Clean Clean-Cell™ Cleanroom facility additional client specific parameters are taken into consideration, including:

Variables	Clean-Cell™ 1.x	Clean-Cell™ 2.x	Clean-Cell™ 3.x	Clean-Cell™ 4.x
Cleanliness Class	Yes	Yes	Yes	Yes
Air Change Rate	Yes	Yes	Yes	Yes
Differential Pressure	Yes	Yes	Yes	Yes
Filter Efficiency	Yes	Yes	Yes	Yes
Process	Yes	Yes	Yes	Yes
Personnel	Yes	Yes	Yes	Yes
Ambient Conditions			Yes	Yes
Temperature			Yes	Yes
Relative Humidity			Yes	Yes
Process Heat Gain			Yes	Yes
Process Exhaust			Yes	Yes

As a rule of thumb, for cleanliness we can consider the following air change rates as a starting point:

ISO Class 9: >10 AC/H (non-unidirectional flow)
ISO Class 8: >15 AC/H (non-unidirectional flow)
ISO Class 7: >30 AC/H (non-unidirectional flow)
ISO Class 6: >60 AC/H (non-unidirectional flow)
ISO Class 5: >120 AC/H (non-unidirectional flow)
ISO Class 5: 0.3m/s (unidirectional flow)
ISO Class 4: 0.45m/s (unidirectional flow)

The project design review process will establish the appropriate air change rate to satisfy cleanliness and temperature control requirements, considering: