Basic functioning of a cleanroom: The path of a particle in the cleanroom

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Cleanrooms are at the heart of many highly sensitive production and research processes. But how exactly does a clean room work? Let's explore the technologies and mechanisms that ensure these environments remain particle-free and germ-free. To illustrate this, we accompany a particle on its journey through a clean room.

From penetration to removal: The path of a particle in a clean room

1. Outside air: The particle is approaching

The outside air is often polluted with particles such as dust, pollen and microorganisms that could potentially enter the clean room. In typical cleanroom solutions, this risk is averted by HEPA filters in the supply air systems, which remove up to 99.995% of all particles over 0.3 microns【1】【3】. However, our room-in-room solutions offer a decisive advantage: Even in environments such as warehouses, where comprehensive pre-filtering is difficult, they make it possible to create a highly controlled cleanroom environment through careful sealing, intelligent airflow and additional measures. This allows you to ensure the required air purity even in demanding initial situations and achieve maximum efficiency in your processes.

2. Entry process: Control through locks

‍The process of entry into a clean room is crucial, as people and their clothing are the biggest source of particles. As a result, the focus today is less on airlocks that spray off remaining particles and more on effective changing processes. Putting on lint-free cleanroom clothing, including overalls, caps, and shoe covers, is essential to minimize particle entry.

In addition, the correct handling of materials and a structured access process ensure that particulate sources from outside do not enter the clean room. Changing into the correct cleanroom clothing is therefore the most important measure to ensure a contamination-free environment【2】【4】.

3. Clean room area: Strict air control

There is a precisely coordinated system inside the clean room:

• Airflow control: A low-turbulence displacement flow conducts clean air laminarly (unidirectionally) across the room and removes potentially contaminated air downwards. This system is essential to achieve even high purity classes such as ISO 5【3】【4】.
• Pressure differences: Higher pressures in the purest areas prevent particles from entering from adjacent zones【2】.

The remaining particles are either removed by continuous air circulation or captured on smooth, easy-to-clean surfaces.

4. HEPA filter: The heart of cleaning

The particles that make it into the clean room air are removed from the air circuit by high-performance HEPA filters. As already in the article HEPA filters: precision technology for clean air and the highest standards explained, these filters work with a combination of inertial deposition, diffusion and electrostatic attraction【3】【4】.

The technology behind purity

The processes described are supported by the following essential technologies:

• materials: Smooth, anti-static and chemical-resistant surfaces ensure that particles do not stick. Wall and ceiling elements are specially coated to facilitate cleaning processes and minimize the risk of cross-contamination【4】.
• Ventilation systems: Fans keep the air in constant motion and ensure continuous air exchange. This constant circulation prevents the accumulation of particles and ensures that the air quality remains consistently high in all areas of the cleanroom【2】【3】.
• Automated lock control: Intelligent locks with internal pressure sensors and airflow analyses prevent accidental air exchange between cleanroom areas and the outside world. They ensure that contamination is prevented at the point of entry【4】.

conclusion

Cleanrooms function thanks to a combination of filtration, airflow control and pressure regulation. They provide a controlled environment in which products and processes are protected from contamination. At Nordair Systems, we understand the importance of these technologies and are happy to help you plan and implement your cleanroom solution.

Source citations

1. ISO 14644-1: Cleanrooms and associated controlled environments — Part 1: Classification of air cleanliness by particle concentration.
2. ISO 14644-4: Cleanrooms and associated controlled environments — Part 4: Design, construction, and start-up.
3. Whyte W., Ward S, Agricola K (2018), Ventilation effectiveness in cleanrooms, European Journal of Parenteral and Pharmaceutical Sciences, 23 (4).
4. Ljungqvist B., Reinmuller B. (2020), People as a Contamination Source in Pharmaceutical Cleanrooms. DOI: 10.5731/pdajpst.2020.012054.

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