Dynamic Pass Box
A Dynamic Pass Box (also called an active pass box or dynamic transfer hatch) is a wall-mounted cleanroom transfer chamber that moves materials between areas of different cleanliness while actively filtering the air inside the chamber. Unlike a static pass box, it has a powered HEPA-filtered air-circulation system to purge particles during and after transfer.
How Dynamic Pass Box works
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An operator opens only the outer door, places the item inside, and closes it.
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The interlock prevents the opposite door from opening until the cycle is complete.
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A blower recirculates air through a pre-filter and HEPA filter, removing airborne contamination from the chamber.
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After a set purge/disinfection time—often with UV-C light—the inner-side door unlocks and the material is retrieved.
Key components
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Two interlocked doors: Electromagnetic or mechanical interlocks ensure only one door can open at a time, preventing direct airflow exchange between the two rooms.
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HEPA filtration: Typically a terminal HEPA filter, commonly H14-grade, with a washable prefilter upstream to extend filter life.
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Motor-blower system: Creates vertical, recirculating airflow to continuously clean the transfer chamber.
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UV-C lamp: Used for surface disinfection when both doors are closed; it is not a substitute for validated cleaning.
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Stainless-steel construction: SUS 304 is common; SUS 316L may be specified for more corrosive or higher-hygiene applications.
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Controls and alarms: Door-open alarms, cycle timers, LED lighting, and sometimes pressure gauges or DOP/test ports for filter validation
Typical applications
Dynamic pass boxes are used in pharmaceutical cleanrooms, aseptic filling and compounding areas, medical-device manufacturing, laboratories, biotechnology, electronics, and food-production environments where materials must enter or exit classified zones without frequent door openings.