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Pass boxes are used to transfer material from lower cleanliness areas to higher cleanliness areas or vice versa to classified areas and are also known as hatches. The pass box acts as a barrier between the two cleanliness level areas.
Pass boxes are used to transfer material for mixing, granulation or sterilization in production areas and for sterilization and incubation in microbiology laboratories. In some cases, equipment parts are also moved through pass boxes in the sterile manufacturing area.
Pass boxes help prevent air flow from one area to another while moving material. One door of the pass box opens at a time and both doors cannot be opened simultaneously. Pass boxes shall have an interlocking system.
Pass boxes are of two types – a) Dynamic pass box b) Static pass box
a) Dynamic pass box: Dynamic pass box works like an airlock or laminar air flow unit. Clean air enters the pass box and prevents contamination from entering. Dynamic pass boxes can be cascade, sink or bubble type like airlocks in pharmaceuticals.
b) Static Pass Box: Static pass box is simple box placed between two areas and also known as passive pass box. Areas with high levels of cleanliness must have high pressures that help prevent contamination from entering sterile areas.
Ultra-violet lights are also installed in pass boxes to remove contamination that may enter during material transfer. It should be replaced after 1000 burning hours. Pass boxes should be cleaned with disinfectant at regular intervals.
Functionality of pass box should be checked and verified. Validation can be done by expressing known populations of bacterial cultures.
