Kasus perusahaan terbaru tentang Guangzhou Cleanroom Construction Co., Ltd. sertifikasi

In pharmaceutical workshops, biological laboratories, and food processing plants, different areas cannot directly connect by opening doors in order to maintain air cleanliness. So how are materials, samples, and small equipment transferred without causing contamination?
The solution is a pass box.

I. Definition and Core Function of a Pass Box

A cleanroom pass box is an auxiliary device installed at cleanroom entrances or between rooms of different cleanliness levels. Its primary function is to allow small items to be transferred between clean areas, or between clean and non-clean areas.

The core purpose of its design is to reduce the frequency of cleanroom door openings. Every time a cleanroom door is opened, airflow disturbance occurs and contaminants may enter. Acting as a buffer zone, the pass box minimizes cross-contamination risk and reduces disruption to the clean environment.

II. Working Principle: How Does It Block Contamination?

A pass box is typically embedded into a wall, with each side facing a different clean area. Both doors are equipped with sealing strips to ensure airtightness.

The most critical technology is the interlocking system. When one door is opened, the opposite door is automatically locked and cannot be opened (or an indicator light shows it is unavailable). This physically prevents both doors from being opened simultaneously, effectively blocking airflow penetration between areas of different cleanliness levels.

This mechanism functions like an “airlock,” preventing contaminated air from flowing from lower-grade areas into higher-grade clean zones.

III. Main Types and Selection Guidelines

Based on working principles and additional functions, pass boxes are generally divided into three main types. These categories are key parameters to confirm during procurement.

1. Mechanical Interlock Pass Box

The interlocking mechanism is achieved through an internal mechanical structure. If one door is not fully closed, the other door cannot be opened.

Advantages:

• High reliability

• No power supply required

• Suitable for explosion-proof or special environments

2. Electronic Interlock Pass Box

Controlled by integrated circuits and electromagnetic locks. Usually equipped with indicator lights to show the status of the opposite door.

Compared with mechanical interlocks, electronic systems are more responsive and allow integration of accessories such as UV sterilization lamps and buzzers.

3. Self-Cleaning / Air Shower Pass Box

This is a more advanced type. Based on a standard pass box structure, it includes an internal fan and a HEPA filter.

During material transfer, high-speed clean air (typically ≥ 20 m/s) blows from the top to remove dust particles from the surface of the items. Filtration efficiency can reach 99.99%.

This type features built-in purification capability and is suitable for core areas requiring extremely high cleanliness standards.

Additionally, in terms of material and structure:

• Most pass boxes are made of 304 stainless steel to ensure smoothness and corrosion resistance.

• For long-distance transfer needs, the work surface can be designed with non-powered rollers to reduce operational effort.

IV. Technical Features and Key Parameters

When selecting or evaluating a pass box, the following technical indicators should be carefully reviewed:

• Material: Internal chamber usually made of stainless steel; external panel can be stainless steel or powder-coated cold-rolled steel.

• Interlock Type: Mechanical or electronic. Some models include UV sterilization lamps (commonly operated for 30 minutes per cycle).

• Sealing Performance: EVA sealing materials or specialized gaskets ensure airtightness.

• Common Sizes: For example, a 600-type model typically has internal dimensions around 600 × 600 × 600 mm. Customization is available according to wall openings.

V. Proper Operation and Maintenance

To ensure the pass box functions effectively and does not become a contamination source, proper Standard Operating Procedures (SOP) are essential.

1. Single-Side Door Principle
   Strictly follow the “one door open at a time” rule. After placing materials inside and closing the outer door, the inner operator may then open the opposite door to retrieve the items.

2. Cleaning and Disinfection
   After each transfer, wipe down internal surfaces. Regularly activate the UV lamp for sterilization.

3. Precautions
   If one door cannot be opened, do not force it. This is usually due to the interlock protection mechanism because the opposite door is not fully closed. Forcing it may damage the locking device.
   Additionally, no materials should be stored inside the pass box for extended periods.

Conclusion and Recommendation

The pass box is an essential physical barrier in modern cleanroom facilities. It is not only a material transfer channel but also a key device for maintaining pressure differentials, ensuring process environment integrity, and achieving GMP and other regulatory certifications.

If you are planning a new cleanroom project or upgrading existing logistics channels, it is recommended to select the appropriate pass box model based on:

• Your cleanliness classification (e.g., Grade D, C, or A)

• The characteristics of transferred items (whether they carry microorganisms or generate particles)

Choosing between mechanical interlock models or self-cleaning (dynamic) models should be based on these operational requirements to ensure optimal contamination control and regulatory compliance.