If airflow is the lifeblood of cleanrooms, pressure differentials are the arteries that guide it. Pressure cascades ensure air moves from cleaner zones to less-clean zones, preventing cross-contamination.
This article explores the science, standards, and real-world applications of pressure differentials in cleanroom facilities across semiconductors, pharmaceuticals, and medical devices.
Positive Pressure: Maintains clean air inside by pushing air outward.
Negative Pressure: Contains hazardous substances by pulling air inward.
ISO 14644 requires controlled pressure cascades.
EU GMP Annex 1 mandates documented differentials in sterile processing.
Sterile Grade A/B areas: Positive pressure vs. background Grade C/D.
Cytotoxic drug manufacturing: Negative pressure in containment.
Positive pressure in lithography and wafer inspection areas.
Pressure balancing critical to particle transport prevention.
Implants: Positive pressure protects sterility.
Diagnostics: Mixed positive/negative depending on biological hazards.
Manometers & Pressure Sensors: Monitor differentials continuously.
Foggers: Visualize leakage or directional flow.
Alarm Systems: Alert when pressure is out of range.
Door openings collapsing pressure cascade.
Poorly sealed HVAC ducts.
Incorrect balance between zones.
Pressure differentials are invisible but critical. By maintaining pressure cascades, facilities control contamination flow and prove compliance to regulators. Tools like ultrapure foggers provide visible confirmation that invisible barriers are intact.
Since 1992, Applied Physics Corporation has been a leading global provider of precision contamination control and metrology standards. We specialize in airflow visualization, particle size standards, and cleanroom decontamination solutions for critical environments.
