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 µm0,2 µm0,3 µm0,5 µm1 µm5 µm
31 000
410 0002 3701 02035283be
5100 00023 70010 2003 520832d, e, f
61 000 000237 000102 00035 2008 320293
7ccc352 00083 2002 930
8ccc3 520 000832 00029 300
9gccc35 200 0008 320 000293 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:

  1. Cleanliness
  2. Temperature
  3. Humidity
  4. Pressure
  5. Number of air changes per hour
  6. 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

What our customers say…

“Throughout the project Airology provided us with guidance and their expertise to ensure that the installation met our specific requirements and was completed on time. We are delighted with our state of the art Clean Room and the professional approach and support given to us by the Airology team was invaluable.”

Andrew Stringer Managing Director, Entaco Ltd

“During the initial design and build we worked closely with Airology to create a facility that will provide one of the most comprehensive GMP stability storage and testing services in Europe. Working with Airology as the principal contractor enabled us to deliver a significant building project, on-scope, on-time and on-budget.”

Mark HammondManaging Director, Intertek Melbourn Scientific

“We have used Airology extensively to install air conditioning in Grosvenor House so wanted them to handle the M & E but we also wanted a single locally based supplier for the refurbishment contract.  Airology were able to provide a comprehensive service including the raised floor, ceilings, decoration and carpeting as well as the M & E  and the project came in on budget, on time and the quality was excellent.”

Mark RobertsManaging Director, Loxton Developments Ltd

“Airology provided us with a bespoke, managed development which has allowed us to double our production output. The service and communication which we received at all stages of the project was excellent and any impact on our production was kept to an absolute minimum. Malosa Medical would definitely recommend Airology.”

Will Stewart Operations Manager, Malosa Medical

“Airology completed our installation with a high degree of professionalism and knowledge. P3 would have no hesitation in recommending the company for similar projects.”

Simon TalbotManaging Director, P3 Medical Ltd

“We would like to thank you for the way the works were carried out to a high standard with the minimum of disruption. From concept to completion your staff were very helpful and professional throughout. We would be pleased to recommend you in the future without hesitation.”

Dr SilvaPerfect Image Consultants

“The quality of the work has been to a high standard and the people who have worked on the project have been exceptional. There were some challenges to be dealt with, but as we thought the Airology team was first class at solving the problems and kept the project to time and to budget.”

Nigel SouthernRidgeway Biologicals

“I have worked with Airology for several years and always found them to be reliable and responsive in regard to the servicing and maintenance of our HVAC equipment.”

Colin Welsh Orbit Group