air shower

Air showers are enclosed chambers positioned at cleanroom entrances that remove particulate contamination from personnel and materials before entry. High-velocity HEPA-filtered air jets (typically 20-25 m/s) blow from multiple directions, dislodging particles from clothing, hair, and surfaces. The contaminated air is then filtered and recirculated. Standard air shower cycles last 15-30 seconds with interlocked doors preventing bypass. Personnel stand with arms raised, rotating to ensure complete coverage. The system typically achieves 90-95% particle removal efficiency for particles >0.5μm. Air showers are critical in semiconductor fabs where even microscopic contamination can cause defects. They complement gowning procedures but don't replace them. Modern systems include features like adjustable cycle times, occupancy sensors, and integration with facility access control. Regular maintenance includes HEPA filter replacement, nozzle cleaning, and airflow verification. While effective for loose particles, air showers cannot remove all contamination, making proper gowning protocols essential.