Pass Box in Pharma

A Pass Box (also called a pass-through hatch or transfer hatch) is a sealed chamber built into a cleanroom wall that lets materials move between two areas without people entering the room. Its main purpose is to protect the cleanroom’s cleanliness, pressure cascade, and contamination-control strategy.

How Pass Box in Pharma works

It has two interlocked doors—one opening into each room. The interlock ensures only one door can be opened at a time, preventing direct airflow between areas of different cleanliness.

Typical use flow:

1. Operator places decontaminated material in the pass box from the lower-cleanliness side.

2. Closes and, where applicable, disinfects/UV-treats the chamber.

3. The receiving-side operator opens the opposite door only after the first door is closed.

4. Material is removed into the higher-cleanliness area.

5. Main types:

   Type	Also called	Air handling	Typical use
   Static pass box	Passive pass box	No forced airflow; relies on sealed, interlocked construction	Transfer between areas of similar cleanliness or where an air purge is not required.
   Dynamic pass box	Active pass box	Has a blower and HEPA-filtered airflow; may include air shower or purge function	Transfer between areas of different cleanliness grades, especially where particle removal and pressure control are important.

   Dynamic units may be designed as cascade, sink, or bubble types, depending on whether air flows from clean to less clean, from less clean to clean, or is contained within the box.

   Common features

   • Stainless-steel construction, usually SS 304 or SS 316, with smooth cleanable surfaces.

   • Electromechanical or electronic door interlocks.

   • UV-C lamps for surface disinfection, where justified and validated.

   • HEPA-filtered forced airflow in dynamic models.

   • Viewing windows, internal lighting, door status indicators, and sometimes touchless operation.

   • Pharma applications

     Pass boxes are used to transfer raw materials, packaging components, tools, samples, and finished or in-process goods into cleanrooms; they may also be used to remove waste without personnel crossing through the controlled area.

     They are especially important in sterile and aseptic manufacturing, microbiology laboratories, and areas where maintaining differential pressure between rooms is critical.