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How are cleanrooms classified?
Cleanrooms are classified according to the number and size of particles permitted per volume of air.
ISO Standard Cleanrooms
The ISO 14644-1:2015 – ‘Classification of Air Cleanliness’ is the European standard for cleanroom classification.
Industries need various levels of “clean air” in their cleanrooms depending on the type of work/procedure to be carried out there. If you are not sure what classification of cleanroom you require, speak to one of Airology’s experts today. Call: 01527 894 279
Airology offer custom ISO Cleanrooms and has the knowledge to guide you to the right decision.
Table 1 – ISO Classes of air cleanliness by particle concentration
| ISO Class number (N) | 0,1 µm | 0,2 µm | 0,3 µm | 0,5 µm | 1 µm | 5 µm |
|---|---|---|---|---|---|---|
| 1 | 10b | d | d | d | d | e |
| 2 | 100 | 24b | 10b | d | d | e |
| 3 | 1 000 | 237 | 102 | 35b | d | e |
| 4 | 10 000 | 2 370 | 1 020 | 352 | 83b | e |
| 5 | 100 000 | 23 700 | 10 200 | 3 520 | 832 | d, e, f |
| 6 | 1 000 000 | 237 000 | 102 000 | 35 200 | 8 320 | 293 |
| 7 | c | c | c | 352 000 | 83 200 | 2 930 |
| 8 | c | c | c | 3 520 000 | 832 000 | 29 300 |
| 9g | c | c | c | 35 200 000 | 8 320 000 | 293 000 |
Table1: ISO Cleanroom Classification Information:
a. All concentrations in the table are cumulative, e.g. for ISO Class 5, the 10 200 particles as shown at 0,3 ΜM include all particles equal to and greater than this size.
b. These concentrations will lead to large air sample volumes for classifications. Sequential sampling procedure may be applied; see Annex D
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 1 ΜM make classification at this particle size inappropriate, due to potential particle losses in the sampling system.
f. In order to specify 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. (See C.7.)
g. This class is only applicable for the in-operation state.
More about cleanroom classification:
Cleanrooms are designated as controlled environments in which the concentration of airborne particles is carefully regulated. Their construction and operation are tailored to minimise the introduction, generation, and retention of particles and microbes within the space, while also controlling other relevant parameters like temperature, humidity, and pressure.
Impact of Particle Size on Classification
The cleanliness level, or ISO Class, of a cleanroom is determined by the concentration of airborne particles larger than 0.5µm per cubic metre. When a cleanroom is designed and built in a pristine environment using non-particulating materials, its cleanliness is primarily influenced by the airflow.
For instance, if a customer requires a cleanroom with fewer than 100 particles per square metre, they may opt for an ISO 5 cleanroom. However, the size of the particles matters significantly. A particle of 0.5 microns has different implications than a particle of 5 microns. Mistakenly assuming a particle to be 0.5 microns when it is actually 5 microns can lead to an incorrect classification. Instead of an ISO 5 cleanroom, it would be designated as an ISO 8 cleanroom from a cleanroom classification perspective.
Relationship between Contamination and Cleanroom Classification
Modular cleanrooms must be designed, constructed, and operated according to the cleanliness classification defined in ISO 14644-1.
The required level of cleanliness for a cleanroom depends on the specific tasks performed within it. Products that are highly susceptible to contamination necessitate higher cleanliness standards. Once a classification is determined, the cleanroom must be maintained to meet the specifications for:
- Cleanliness
- Temperature
- Humidity
- Pressure
- Number of air changes per hour
- Flow rate
Cleanroom ISO Classification
Cleanrooms are classified into ISO Class 1 (the cleanest) through ISO Class 9, with lower ISO ratings indicating a cleaner environment.
For example, an ISO Class 6 cleanroom is rated at 35,200 particles per cubic metre, where the concentration of particles larger than 0.5 microns must not exceed 35,200 per cubic metre.
Our commitment to quality is evident in every project we undertake – delivering innovative class leading solutions for all our projects..
We work closely with clients from every sector of industry including pharmaceutical, medical, veterinary, catering, research, engineering, and technology fields.
Airology can provide a complete bespoke turnkey solution for your project, from concept to completion, focusing on the design, manufacture and construction of innovative cleanroom and controlled environment solutions.
7 key decisions when creating a cleanroom environment
1. Decide how it’s to be used
2. Decide how it should be classified
3. Decide on the right environment
4. Decide what size it should be
5. Decide how impurities will be extracted or filtered
6. Decide on the right lighting condition
7. Decide how secure your facility needs to be
Industries Covered…
Below are are just some of the main industries we service. We can work with companies in near enough all fields so please do not hesitate to get in touch with your requirements today!