what is very low differential pressure i.e 1 pascal?
our atmospheric pressure is 100 000 Pa! A butterfly passing by causes a pressure change of 2,5 Pa

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

Whether it is cleanroom, greyroom, data center, operating theatre or filling system: Lowest differential pressures between the different rooms or zones must be sustained in order to avoid the in-flow of contaminated air.

Continuous measurement and control of these low differential pressures are required(according to ISO 14644: 5 to 20 Pa). This must be proven annually in accordance with ISO 14644 (against zero potential and against neighbouring rooms).

Solution: sensor and systems to measure single or multiple points, with or without integrated display, with or without signal outputs for centralized control, with or without single or multiple loggers and alarm GSM modems.