What Is the Difference Between a Static and a Dynamic Pass Box?

Introduction

In cleanroom operations, controlling cross-contamination during material transfer is essential. That’s why pass boxes—also called transfer hatches—are installed between controlled and non-controlled areas.

But not all pass boxes are the same. Two main types are used in cleanroom environments: Static Pass Boxes and Dynamic Pass Boxes. Understanding their differences will help you choose the right one for your process needs.

1. What Is a Static Pass Box?

A Static Pass Box is designed for transferring materials between areas of the same cleanliness class—for example, between two ISO 7 zones.

Key Features:

l No air circulation or filtration system.

l Simple interlocking mechanism that prevents both doors from opening at once.

l Often equipped with UV sterilization for surface disinfection.

Typical Applications:

l Laboratories or production rooms where cleanliness levels are equal.

l Environments where airborne particle control is not a major concern during transfer.

In short: Static pass boxes are ideal when no air pressure differential or airflow management is required.

2. What Is a Dynamic Pass Box?

A Dynamic Pass Box, also known as an Active Pass Box, transfers materials between areas of different cleanliness grades—for example, from ISO 8 to ISO 6 rooms.

Key Features:

l Equipped with a HEPA or ULPA filtration system and airflow circulation.

l Features automatic blowing or air shower function to remove loose particles from surfaces.

l Includes differential pressure gauges for monitoring pressure balance.

l Can include UV sterilization and LCD-based programmable controls for customized operation cycles.

Typical Applications:

l Pharmaceutical, biotech, and semiconductor cleanrooms.

l Areas requiring particle removal before entry into a cleaner zone.

In short: Dynamic pass boxes actively maintain cleanliness integrity by using filtered airflow and pressure control.

3. How Advanced Pass Boxes Improve Both Models

Modern cleanroom facilities often choose multi-function pass boxes that integrate the best of both worlds.

For example, the latest models—like our High-Compliance Multi-Function Pass Box—feature:

l Redundant Contamination Control: Combining interlocks, UV sterilization, and automatic blowing for triple protection.

l Validation Ready Design: With PAO injection ports and differential pressure gauges, making qualification easy for FDA/EMA audits.

l Automation and Intelligence: The LCD controller automates air and sterilization cycles, ensuring repeatable and reliable performance with minimal human error.

These innovations ensure that every transfer step meets the highest standards of GMP (Good Manufacturing Practice) and ISO cleanroom compliance.

4. Choosing the Right Pass Box for Your Application

If your process involves cross-grade transfer, sensitive components, or pharmaceutical materials, a Dynamic Pass Box is the superior choice. For simpler, equal-grade transfers, a Static Pass Box remains a cost-effective solution.

Conclusion

While both static and dynamic pass boxes serve the same fundamental purpose—safe material transfer in clean environments—their working principles differ significantly.

A Static Pass Box offers simplicity for equal-cleanliness areas, while a Dynamic Pass Box ensures active contamination control through filtration, airflow, and automation.

With innovations like interlock redundancy, UV sterilization, automatic air blowing, and intelligent LCD control, modern pass boxes now provide unmatched reliability, validation readiness, and operational efficiency—making them essential for today’s regulated cleanroom industries.