In fluid mechanics, laminar flow describes an air movement in which all air particles flow parallel and uniformly in one direction. In cleanrooms, laminar flow is achieved by special
filter fan units (FFU)
generated. These consist of powerful fans and high-performance filters that remove even the finest particles from the air. The cleaned air then flows vertically downwards from the ceiling – either directly out of the cleanroom or back into a recirculation circuit.
Why laminar flow is indispensable in the cleanroom
Air quality in the cleanroom is not just a question of cleanliness, but a basis for production. At the heart of a laminar flow system is the defined air flow. Laminar flow ensures that:
- particles are immediately removed from the work area.
- Contaminated air is not recirculated.
- The air is exchanged evenly.
- standards such as ISO 14644 or GMP guidelines are complied with.
In the pharmaceutical industry, a single dust particle can jeopardize the entire production run. In semiconductor production, a tiny foreign body can lead to high losses.
The technology behind it – How laminar flow is generated
A laminar flow system typically consists of:
- HEPA or ULPA filters – they clean the air of particles down to a size of 0.12 micrometers or smaller.
- Flow-guiding elements – grilles or perforated panels distribute the air evenly.
- Constant flow velocity – Usually 0.3 to 0.45 meters per second.
- Straight-line guide – Vertical (from top to bottom) or horizontal (from the rear wall to the front).
Laminar flow is at the heart of a functioning cleanroom. It not only guarantees compliance with legal regulations, but also protects products and processes, e.g. in the filling of pharmaceuticals or in semiconductor technology.
