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.
For preventing cross-contamination coming from adjacent areas, several guidelines refer to a positive room-pressure of about 5- 20 (10-15) Pascals (Pa) as an essential factor for airflow from higher cleanliness to a lower cleanliness graded area under static conditions. To manufacturers of pharmaceutical products and the authorities controlling them, this cascaded pressure regime and room pressurization is seen as an essential element in preventing contamination (migration of particles) from adjacent outside areas.
Qualification tests are carried out to guarantee optimum product quality from all manufacturing and pharmaceutical research companies. These tests verify whether ambient cleanroom conditions affect product quality. If environmental cleanroom parameters affect the product, reviews are conducted with regards how conditions can be reduced, so that high output standards are adhered to.
Differential pressure refers to the difference in air pressure from one location to another within a system. In cleanrooms, maintaining the right amount of differential pressure—either positive or negative—is essential to preventing contamination.
In most large-scale FDA-regulated pharmaceutical manufacturing operations, it is required that the product be manufactured in a clean room classified between Class 100 and Class 100,000. In an operation where medical tubing is being extruded, the classification would likely be Class 100,000. In a process where inject-able drugs are being manufactured, the classification would most likely be Class 100 or Class 1000.
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