The HEPA filter, or High Efficiency Particulate Air filter, is an essential component in cleanroom environments, commonly found in various cleanroom equipment, including the Pass Box. It plays a crucial role in maintaining the cleanliness of the air by filtering out particles. However, not all Pass Boxes require a HEPA filter. When replacing the filter for the Pass Box, certain precautions need to be taken into account.

Which type of Pass Box has a HEPA filter?

If you've been following VCR's articles for a while, you're probably familiar with the two main types of Pass Boxes: Static and Dynamic. Additionally, within the Dynamic Pass box category, there are variations such as Air Shower Pass Box, laminar flow Pass Box, and even VHP Pass Box (a device used for special disinfection). What they all share is their cleaning capability. In contrast, Static Passboxes lack this feature and are primarily used for interlocking and sterilization with UV light.

By now, we likely understand which type of Pass Box requires a HEPA Filter: the Dynamic Pass Box.

Dynamic Pass Box needs HEPA filter
Dynamic Pass Box needs HEPA filter

See also: What is a Pass Box?

So why does Dynamic Pass Box need HEPA filter?

Dynamic Pass Boxes are designed for transferring items between areas with varying levels of cleanliness, aiming to minimize door openings and thus reduce cross-contamination between clean rooms. When transferring items between environments of different cleanliness levels, there's a risk of contamination, especially when moving from a less pure environment. Therefore, the pass boxes need to be equipped with cleaning capabilities to address any contaminant particles on the samples. This is why Dynamic Pass Boxes require HEPA Filters.

Self-cleaning pass boxes draw in air and pass it through HEPA filtration, ensuring that the air entering the workspace is clean, with particles of 0.3 micrometers or larger filtered out at a rate of 99.99%. Subsequently, the pass box cleans the samples before introducing them into the clean room.

See also: How to choose the right pass box?

Things to Consider When Changing the HEPA Filter in a Dynamic Pass Box

Here are some important points to keep in mind when replacing HEPA filter in cleanroom pass box:

  • When replacing the HEPA filter in a self-cleaning pass box, ensure careful handling during opening and installation to prevent any damage to the filter paper. Avoid touching the filter paper to prevent any potential damage.

  • Before installing the HEPA filter in a Dynamic Pass Box, inspect it under adequate lighting to check for any gaps or damage caused during transportation. If there are any punctures or openings, the filter should not be used.

  • During the replacement process, start by removing the control panel and cleaning any dust. Then, remove the old filter and replace it with a new one, making sure to align the arrow marks on the filters correctly (to match the airflow direction). Finally, reinstall the control panel.


Structure of Pass Box with HEPA Filter

The HEPA filter plays a crucial role in the Dynamic Pass Box, emphasizing the importance of proper maintenance and replacement procedures. Attention to the aforementioned issues during replacement ensures optimal efficiency of the filter replacement process.