Cleanroom: Controlled Environment for Sterile Processes and Products
Last updated: 04 February 2026
A cleanroom is a controlled environment in which the concentration of airborne particles and the microbiological loadare kept within defined limits through technical measures. In pharmaceutical production, the goal is to prevent contamination to ensure the sterility of the products.
What Are the Advantages of Cleanrooms?
The use of cleanrooms is much more than a regulatory requirement; it is the foundation for the control of complex manufacturing processes. Especially in aseptic production, controlled environments enable a maximum degree of reproducibility and safety, benefiting manufacturers and end consumers alike:
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Compliance with 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 – such as Blow-Fill-Seal systems – reducing the need for manual interventions and thus potential sources of contamination.
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Ensuring high product quality: through the targeted minimization of impurities and defective products.
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Increasing 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 range of industries. This begins with biotechnology, where they are primarily used in work on cell cultures or active ingredient production. The pharmaceutical industry requires cleanrooms, for example, for the production of sterile medicines and the aseptic filling of pharmaceutical products.
Rommelag's Blow-Fill-Seal technology offers a significant advantage here: since the forming, filling, and sealing take place in a closed system, the critical zone can be locally protected with Grade A air. This allows the surrounding cleanroom to be operated in GMP Grade C, depending on the application, which reduces operational complexity.
Cleanrooms also enable reliable chip production and wafer processing in the semiconductor and microelectronics industry. In the field of medical technology, these rooms are primarily required for the manufacture of implants, catheters, and testing devices.
Which Aspects are Decisive?
To ensure the integrity of a cleanroom over the long term, physical and microbiological parameters must be precisely coordinated and continuously monitored. The following factors form the levers for a stable Contamination Control Strategy (CCS):
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Air quality: The most important parameter for air quality is the number of particles contained in it. In pharmaceutical production, monitoring the germ count is also mandatory.
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Air temperature: Often, the room temperature is also a relevant aspect, whereby it should be constant – at least within a certain range.
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Air humidity: The moisture content of the air must permanently be such that it does not impair product quality and prevents static charges.
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Air pressure: Usually, overpressure prevents the entry of contaminants in interaction with a ventilation system and special filters. When handling hazardous substances, underpressure can conversely ensure that these do not escape to the outside.
What are Cleanroom Classes?
The requirements for the cleanliness of rooms can vary depending on the industry, process, and product. This led to the concept of cleanroom classes. The individual classes indicate which cleanliness requirements a room must meet. Previously, country- and industry-specific guidelines dominated here. In the meantime, however, worldwide uniform standards such as ISO 14644 exist. Further information on the concept of cleanroom classes is provided in our glossary.
How does a Cleanroom work?
The design of cleanrooms differs depending on the industry and requirement profile. Especially with very high requirements, there are often hierarchically arranged premises in which the degree of cleanliness increases successively through various measures. 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 systems – serve this purpose. Providers like Rommelag also specifically separate personnel and product through automated technology – such as Blow-Fill-Seal systems – and thus minimize the contamination risk 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. HEPA filters (High Efficiency Particulate Air) are used together with the ventilation systems.
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
EN ISO 14644
EN ISO 14644 refers to a European standard for cleanrooms and controlled environments. In Germany, it was published in the form of DIN EN ISO 14644. The operationalization of the term cleanliness takes place here based on the particle concentration in the room air. The standard deals not only 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. The amount of particles per cubic meter of air must be lower the lower the cleanroom class is.
EU GMP Guidelines, Annex 1
This "Good Manufacturing Practice" originates from medicine 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 compared roughly to ISO Class 5, but demands even stricter requirements regarding the maximum allowed particles per cubic meter in the operating state. In addition, there is a microbiological monitoring with limit 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. The guidelines are based on current research and EN ISO 14644.