Application cleanroom

Owing to the precise measurement of differential pressure, it is possible to regulate the air flow between neighbouring rooms (see illustration below).
Air generally flows from higher to lower pressure. In order to maintain the highest air quality in the critical zone, P1 must be greater than P2, see illustration. Air contaminated with particles thus never flows from the normal or outdoor zone into the critical zone. Typical areas of application are, in addition to clean rooms, also hospitals ( positive pressure in operating theatres, negative pressure in isolation wards), as well as positive pressure maintenance in pharmaceutical or food filling plants

Which pressure differences must exist between individual cleanrooms is defined in the international norm ISO 14644-4: 5 - 20 Pa.