Key differences between static and dynamic pass boxes

One of the systems commonly used in cleanrooms to minimize contamination is the pass box. As the name itself suggests, the primary and only work of this system is to pass materials from one side to the other, between controlled environments of different classes so as to avoid airborne cross-contamination. Should any particulate matter be present on the surface of the material being transferred, it is swiped away during the operation.

The prime feature of a pass box is the interlocking door mechanism – when the door on one side is open the door on the other side remains closed. Pass boxes are known by different names including cleanroom pass-through, the clean transfer window, and transfer hatch, and are widely used in microbiology laboratories in the food, pharmaceutical, and chemical industries.

Cleanroom passes come with different features and sizes, hence, installing the right product is paramount. Here are some things to know when choosing the right cleanroom pass box for your facility.

A pass box is designed in two different types; static and dynamic and it is the user-specific requirement that decides the right design configuration.

Difference between static and dynamic cleanroom pass box

Static pass boxes are used to transfer materials between two rooms of equal cleanliness levels. They are designed for minimal personnel movement. Dynamic ones are used to transfer materials from uncontrolled to controlled environments.

Read more blog: Demystifying Pass-through chambers for cleanroom applications

Dynamic cleanroom pass-through box works like an airlock or laminar airflow unit. Clean air enters the box system and prevents contamination. These boxes may be cascade, sink, or bubble type, similar to airlocks in pharmaceuticals.

1. Selecting the right pass boxes for your cleanroom 

The decision on which type of cleanroom pass-through to invest in must be made depending on the end requirements. 

• When building a new cleanroom or for established cleanrooms, a dynamic box is a clear choice as it offers flexibility and can be used to transfer materials from uncontrolled to controlled environments. The inclusion of a HEPA filter and equipment for complex air handling helps keep contaminants at bay and allows the cleanroom to achieve higher clean certification.
• Static boxes are ideal when ventilation is not required – primarily for moving non-sensitive products between two cleanrooms of equal cleanliness. They must never be used to transfer material between clean and non-clean rooms.

Whichever type of cleanroom pass box suits your need, choose one with flat surfaces so it is easier to clean and maintain. If the standard material of construction is not stainless steel, be sure to request a material that does not adversely react with chemicals in cleaning products.

2. Must-haves in your cleanroom pass box by Fabtech, a modular cleanroom equipment manufacturer

• Your pass box should be integrated with the cleanroom wall system.
•  It should be durable, aesthetically pleasing, and sit flush to the cleanroom walls, so dust accumulation is completely avoided.
• Interlocking is a critical safety feature of any transfer hatch. There should be an indicator light to signal when the door at the other end can be opened.
• These clean transfer windows should have an air pressure drain to keep air pressure under control and maximize safety, and a UV light for enhanced protection and destruction of pathogens. The ultraviolet light is controlled by an interlocking arrangement and is turned off whenever any of the doors are opened

Seamless material transfer by Fabtech’s modular cleanroom solutions

Fabtech’s cleanroom pass boxes have a re-circulatory air system with a certain percentage of air intake as fresh air to keep it under positive pressure. It has a microprocessor-based controller to manage door interlock, UV light–hour meter, door open delay, and other application-based requirements. Validation is per ISO / IEST RP with airflow visualization and specific execution based on application. The material of construction is SS304. Contact the Fabtech Team for a Custom Pass Box Solution and Other Cleanroom Equipment Requirements.