This also works inside fully glazed walls. You can see this well in the flow visualisation. What happens next?
Filter Fan Units (FFU) with integrated high-performance HEPA filters are installed in the cleanroom ceiling, which suck in the air, filter it and blow it into the cleanroom at the desired pressure. The low-particle air flow, also called "laminar flow", displaces the particle-laden air in the cleanroom and directs it back into the recirculation walls through discharge openings on the floor.
Simpler systems, such as cleanroom tents or cleanrooms, can also be operated without a recirculation system. In these cases, 100% of the clean air is discharged via outflow grilles, process openings or the floor gap.