Between rooms of different cleanroom classes, pressure differences between 5 and 20 Pa must be ensured from cleaner room to less clean room. The minimal positive pressure of the cleanroom ensures that no air flows back into the cleaner area from the unclean area when doors are opened. The lowest contamination-level cleanroom itself is also accessed via airlocks for personnel and materials, where strong air currents stir up the particles present and extract them via filter systems. According to DIN EN ISO 14644-3, the pressure difference of a cleanroom to the personnel and material airlocks, to any cleanrooms of other purity classes as well as to the surroundings, must be tested. A test of differential pressure at the filter should also be carried out.

• Measurement of differential pressure requires highly precise measurement technology

• Measurement of differential pressure between rooms and at the filter

Valuable information on measurements of air temperature, relative air humidity and differential pressure as well as on flow velocity testing in cleanrooms

• The most important norms

• Useful tips on measurements

• Measuring instrument requirements