Pass-through chambers (also called pass-through boxes) have become a ‘must’ in many industries over the years. When creating a production process, material flow must be designed in accordance with the various standards the lab must comply with. Two environments in the same lab might have very different hygiene requirements that must be taken into consideration when material is processed from one room to the other. A pass-through chamber is a great way to avoid any issues that would be caused by that.
What is a clean room pass-through chamber?
A cleanroom pass-through chamber, as the name suggests, is a chamber designed for transferring materials in and out of a cleanroom. Its purpose is to move items between controlled areas without requiring staff to leave or re-enter the cleanroom and change gowning. By using a pass-through chamber, materials can be introduced into the cleanroom while minimizing the risk of contamination.
Difference between static, semi-active and dynamic pass-through chamber specifications
| FEATURE | STATIC | SEMI-ACTIVE | ACTIVE | DYNAMIC |
|---|---|---|---|---|
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| Seperate air supply | No, air flows directly from one controlled environment to the other | No, air flows directly from one controlled environment to the other | Yes, built-in fan filter unit (FFU), overpressure with purified air | Yes, integrated fan |
| Filters (HEPA/ULPA) | None | Yes (HEPA/ULPA) | Yes (HEPA/ULPA, high purity) | Yes, integrated HEPA filter |
| ISO classification | ISO7 - ISO8 | Case-dependent, depends on cleanroom requirements | ISO6 - ISO7 | ISO5 - ISO7 |
| Installation complexity | Complex, requires dedicated air supply and exhaust | Moderate, requires dedicated air supply | Simple–moderate, no external infrastructure needed | Simple–moderate, no external infrastructure needed |
| Cleanliness level | Lowest | Medium | High | Highest |
1. Separate air supply
Static and semi-active pass-through chambers are not equipped with their own air supply system; instead, they are connected to the cleanroom’s main ventilation system, which provides the necessary airflow and pressure control.
Active pass-through chambers include a standalone fan filter unit, providing high purity air into the pass-through chamber. By creating overpressure and filtering out the incoming air, they are able to achieve a higher level of cleanliness compared to static and semi-active models.
Dynamic pass-through chambers are equipped with their own air supply as well, which allows them to reach the highest level of cleanliness of all pass-through chambers, highly customisable and do not have any restrictions regarding the installation.
2. HEPA and ULPA filters
All pass boxes are equipped with HEPA filters to capture fine particles. In active models, the filter can also be ULPA, and they include an integrated fan filter unit (FFU) to maintain higher cleanliness standards. The choice between HEPA and ULPA should be based on the cleanroom’s ISO classification and specific contamination control requirements.
3. ISO standard classification
As a result of the different designs, the three main types of pass-through chambers comply with different levels of ISO standards. While static and semi-active pass-through chambers are usually suitable for clean rooms according to the ISO 7 category, active and dynamic pass-through chambers satisfy the requirements of ISO 5 - ISO 6 clean rooms.
General recommendations for compliance and quality assurance
Pass-through chambers are often a critical part of meeting regulatory requirements in cleanroom facilities. Proper installation, routine maintenance, and documented cleaning protocols help ensure compliance with ISO 14644 standards, GMP guidelines, and other industry-specific regulations. Using validated equipment not only protects products and staff but also supports consistent quality assurance.
How often should a static vs. an active pass-through chamber be cleaned and disinfected?
Daily and/or weekly clean room cleaning
In cleanrooms, pass-through chambers must be cleaned and disinfected on a daily basis whenever compounding takes place. A sporicidal treatment is recommended once a month. Cleaning should take place at the end of the compounding day, following a defined sequence that begins with the cleanest areas and is fully documented.
Maintaining a clean room requires both daily and weekly routines and pass-through chambers are also cleaned and wiped dry. Work areas must be disinfected at the end of every shift and in higher ISO class cleanrooms this should be done more frequently. Only cleanroom-approved products should be used to clean the pass-through chamber, such as sterilized disinfectants, deionized or distilled water, and non-ionic, non-foaming cleaning agents that leave no residue. Woven polyester wipes are recommended to prevent contamination and surface damage.
While these cleaning steps are standard for all pass-through chambers, the frequency may differ depending on the model. Static pass-through chambers often require more frequent cleaning due to the lack of filtered airflow, while active chambers with built-in HEPA or ULPA filters can maintain cleanliness longer between cleaning cycles.
