Air showers are an integral part of clean room access control systems and ensure critical manufacturing conditions in such industries as microelectronics, life science, biomedical, aerospace and others. Air showers guarantee that factory equipment is protected from pollutants and contaminating agents.

• Operating principle

The standard Air Shower is designed to accommodate one person. It features an insulated chamber with its own motor fan, facilitating the circulation of air through a HEPA filter. This filtered air is then directed at high velocity (25 m/s) using two rows of nozzles (11 in a row), with an additional nozzle positioned at the top, towards the person inside the chamber. Air, carrying particles released from the individual’s body, is drawn in through a pre-filter (G4), safeguarded by a suction grille, and guided through a duct to the suction opening of the motor fan. Personnel can enter and exit the air shower through a pair of doors that interlock with each other. The operation of the air showers is controlled by software running on a PLC Siemens Logo! with a display. The control panel is situated inside the air shower unit, positioned above the suction grille. The switch box is located in the ceiling inter space and becomes accessible after opening the ceiling panel.

• Cleaning cycle

The cleaning cycle is activated automatically when the door from a grey area opens and closes, and a person is detected inside the chamber. The door to the clean room is automatically blocked when the grey area door opens. Both doors are blocked during the cleaning cycle, which is preset for 30 seconds (can beset between 10-60 s with 5-s intervals). There is a 5 seconds-delay between the end of the cleaning cycle and the door opening. The grey area door can be opened only when the clean room door closes, and the preset delay time elapses.

• Regenerating cycle

After the person has left the Air Shower, the door closes, and the unit is shortly purged at high speed. Alternatively, continuous purging at low airflow rates can be selected.

• Emergency stop switch

In case of an emergency the cycle can be interrupted, and the unit completely switched off using one of the emergencies stop switches. The switch is located inside the chamber and in the clean room or is available as the main switch in the grey area.

• Control modes:

• Standard mode: Cleaning cycle runs when passing from grey to clean room. Moving from a clean room to a grey area does not start the cleaning cycle, only purging (regenerating) cycle.
• Two-way mode: Cleaning cycle runs when passing from grey to clean room and also when leaving clean room.
• One-way mode: Exit from clean room is not allowed through the Air Shower.

• Air shower unit components:

• radial fan with backward-curved blades with EC motor equipped with constant-flow control
• HEPA filter H13/H14 in an aluminum frame 78 mm high, with a gel gasket and protective grid on its clean air side
• suction grille made of perforated painted steel sheet, equipped with a pre-filter G4
• cabinet walls are assembled from 62 mm thick sandwich R-panels (two steel sheets with mineral wool insulation between them), with painted steel sheet facing in RAL 9002 / RAL 9010
• corner ducts with nozzles, each contains 11 nozzles, trough which air is blown at a mean axial velocity of 25 m/s
• ceiling equipment: one nozzle, three LED lights, PIR-motion sensor, and revision doors
• single-leaf ESG glass doors (700 x 2100 mm) in an aluminum frame with a polyester finish, equipped with a drop-down seal, door closer, reversible electromechanical lock and signaling units. The doors cannot be opened at the same time (acts as an air lock)
• stainless steel floor
• switch box