Cleanroom: Controlled Environment for Sterile Processes and Products
Last updated: 28. April 2026
A cleanroom is a controlled environment in which the concentration of airborne particles and the microbiological load are kept within defined limits through technical measures. In pharmaceutical production, the goal is to prevent contamination in order to ensure the sterility of the products.
Which advantages do cleanrooms offer?
The use of cleanrooms is far more than a regulatory mandatory exercise; it is the foundation for the controllability of complex manufacturing processes. Especially in aseptic production, controlled environments enable a maximum level of reproducibility and safety, from which manufacturers and end consumers benefit equally:
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Fulfillment of technical necessities and regulatory requirements: Various products can or may only be created in such a controlled environment.
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Automation of processes: Cleanrooms complement and enable automated manufacturing and filling processes while reducing the need for manual interventions and thus potential sources of contamination.
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Guarantee of high product quality: through the targeted minimization of impurities and defective products.
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Increase in process reliability: thanks to reproducible manufacturing processes under constant production conditions.
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Comprehensive protection: of products and personnel – for example, when handling hazardous materials and substances.
Where are cleanrooms used?
Cleanrooms are essential for a number of industries. This begins with biotechnology, where they are primarily used for work on cell cultures or active ingredient production. The pharmaceutical industry requires cleanrooms, for example, in the production of sterile medicinal products and the aseptic filling of pharmaceutical products. Furthermore, cleanrooms are what first enable reliable chip manufacturing and wafer processing in the semiconductor and microelectronics industry. In the field of medical technology, these rooms are required above all in the manufacture of implants, catheters, and testing devices.
Which aspects are decisive?
To ensure the integrity of a cleanroom permanently, physical and microbiological parameters must be precisely coordinated and continuously monitored. The following factors form the adjusting screws for a stable contamination control strategy (CCS):
Air quality: The most important parameter for air quality is the number of particles contained within it. In pharmaceutical production, monitoring the germ count is also mandatory. This is intended to prevent contamination of manufacturing processes and products.
Air temperature: Often, the room temperature is also a relevant aspect, whereby it should remain constant – at least within a certain range.
Air humidity: The moisture content of the air must permanently be such that it does not impair product quality and that no static charges can occur.
Air pressure: In most cases, overpressure prevents the ingress of impurities in interaction with a ventilation system and special filters. Conversely, when handling hazardous substances, negative pressure can ensure that these do not escape to the outside.
Focus: The Contamination Control Strategy (CCS)
With the revision of EU-GMP Annex 1, the holistic contamination control strategy (CCS) moves into the spotlight. Instead of looking at individual measures in isolation, the CCS requires a site-wide, dynamic document that brings together all technical and organizational controls.
In this process, factors such as plant design, personnel behavior, cleaning processes, and monitoring are combined to proactively prevent cross-contamination and particle entry. The CCS is thus not a one-time certificate, but a living process for the continuous improvement of cleanroom quality.
What are cleanroom classes?
The demands on the cleanliness of rooms can vary depending on the industry, process, and product. This led to the emergence of the concept of cleanroom classes. The individual classes indicate which requirements for cleanliness a room must fulfill. Previously, country- and industry-specific guidelines dominated this field. In the meantime, however, globally uniform standards such as ISO 14644 exist. Further information on the concept of cleanroom classes is provided by our glossary.
How does a cleanroom work?
The construction of cleanrooms differs depending on the industry and requirement profile. Especially where demands are very high, there are often hierarchically arranged premises in which the level of cleanliness – through various measures – increases successively. Two concepts are particularly decisive for cleanrooms.
Firstly, it is about preventing contamination from entering cleanrooms. Cleanroom clothing, floor mats that pick up foreign bodies, aids with minimal abrasion, and suitable machines – such as aseptic filling lines – serve this purpose. Providers such as Rommelag also specifically separate personnel and product through automated technology – such as blow-fill-seal systems – and thus minimize the risk of contamination caused by the human factor.
Secondly, it is about removing particles from cleanrooms or preventing excessive concentrations. Ventilation systems play a central role here. While unidirectional airflow systems direct the air in specific directions, multidirectional systems continuously dilute the particle concentration through mixed-flow. Together with the ventilation systems, HEPA filters (High Efficiency Particulate Air) are used. They are highly efficient particulate air filters that remove at least 99.95% of viruses, bacteria, pollen, fine dust, and allergens from the air.
What are the most important regulations for cleanrooms?
For cleanrooms, three regulations or classification systems are primarily relevant:
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EN ISO 14644
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EU-GMP Guidelines, Annex 1
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VDI 2083
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EN ISO 14644
EN ISO 14644 refers to a European standard for cleanrooms and controlled environments. In Germany, publication took place in the form of DIN EN ISO 14644. The operationalization of the term cleanliness occurs here based on the particle concentration in the room air. The standard does not only deal with the planning and operation of cleanrooms. It also defines – from ISO 1 to ISO 9 – nine different cleanroom classes and provides specifications for regular particle measurements. In this context, the lower the cleanroom class, the lower the amount of particles per cubic meter of air must be.
EU-GMP Guidelines, Annex 1
This "Good Manufacturing Practice" originates from drug production but is relevant today for various industries – such as biotechnology, medical technology, and pharmacy. It defines the four cleanroom classes A, B, C, and D, in which the requirements successively decrease. GMP Class A can be roughly compared to ISO Class 5, but demands even stricter requirements regarding the maximum permitted particles per cubic meter in the operating state. Additionally, there is extra microbiological monitoring with limit value recommendations regarding microbiological contamination.
VDI 2083
This is a catalog of guidelines from the Association of German Engineers (VDI), which is considered the most comprehensive set of rules regarding cleanroom aspects. In contrast to EN ISO 14644 and EU-GMP, however, VDI 2083 focuses on the German or German-speaking region. In this regard, the guidelines are oriented towards current research and EN ISO 14644.