In cleanrooms, laminar flow is created by means of filter fan units (FFU), which consist of high-performance filters and fans. Clean air flows vertically from the ceiling to the floor by means of controlled air flow and transports airborne particles out of the cleanroom or into a recirculation loop.

The room through which the air flows achieves a defined cleanroom quality, as only clean air remains in the room or possible particles are blown away in a directed manner.

The air flow reduces turbulence of existing particles and discharges them through the downward air flow. This makes it interesting for applications where the increased risk of particle formation (e.g. due to friction of moving parts) must be compensated for, e.g. in the filling of pharmaceuticals or in semiconductor technology.