A dynamic pass box is used to transfer the material between non-classified areas to classified areas or between two classified areas with a  class difference.Transfering material from Class D ( ISO 8) to Class C ( ISO 7) would require a Dynamic Pass-Through Hatch.

Air Circulation System and Velocity

A Motor-blower with suspension arrangement for reduced noise levels (Less than 67 dB)  is provided for Dynamic Pass Boxes. A Dynamic Pass box also acts as an ISO 5 ( Class A ) Airlock which could be any of the 3 airlock types  Bubble, Cascade, and Sink. In a dynamic pass box laminar air passed through HEPA EU14 filters (99.997% efficiency down to 0.3 Micron) at an average velocity of  0.45 m/s   is passed over the material. Dynamic Pass boxes have a perforation at the bottom to enable air circulation. No such arrangements are necessary for a Static Pass box.

Timers and Transfer protocol

Dynamic Passboxes have a clean down timer with operation Hold Indicator interlock to put on fluorescent lights only after clean down time is over. The Transfer mechanism of different products could depend on the usage, however, it is a given that the material being transferred has to spend a minimum amount of residence time ( Eg. 2 -5 mins)  inside the chambers so that the contamination causes are overcome and higher air classification is achieved inside the Box. There is a certain amount of time after which UV lights must be turned on for effective disinfection of the microbes and then turned off before the cabinets are to be opened from the other side.

The Validation protocols and procedures for Dynamic Pass Boxes are hence more stringent and elaborate with HEPA Integrity Tests, Air Velocity Test and recovery tests as per ISO -14644-3  as compared to the validation of Static or Passive Pass boxes.