How to Choose the Right Pass Box for ISO Class 5 to 8 Cleanrooms

How to Choose the Right Pass Box for ISO Class 5 to 8 Cleanrooms

Selecting the appropriate pass box (transfer hatch) is critical for maintaining strict contamination control and pressure differentials when transferring materials between different cleanliness zones. Whether you are designing an ISO Class 5 semiconductor facility or an ISO Class 8 general packaging cleanroom, choosing the right pass box configuration ensures regulatory compliance (GMP, ISO 14644-1) and operational efficiency.

1. Understanding ISO Cleanroom Classifications & Transfer Requirements

Contamination control protocols become exponentially stricter as you move from ISO Class 8 toward ISO Class 5. The pass box acts as an airlock barrier to prevent particulate contamination and cross-contamination during material transfer.

• ISO Class 5 & 6 (High Purity / Semiconductor / Sterile Pharma): Require ultra-clean transfer environments, typically utilizing Dynamic Pass Boxes with integrated HEPA/ULPA filtration and laminar airflow.
• ISO Class 7 & 8 (General Manufacturing / Medical Device Assembly / Packaging): Often utilize Static Pass Boxes for transferring materials between similar or adjacent classification zones where mechanical interlocking and sealing are sufficient.

2. Static Pass Box vs. Dynamic Pass Box: Key Differences

Making the right choice starts with evaluating the two primary types of pass boxes:

• Static Pass Boxes:
  • Best for: Transferring items between rooms of equal or similar cleanliness levels (e.g., ISO Class 7 to ISO Class 7), or non-sterile environments.
  • Key Features: Mechanical or electronic interlocking doors (preventing both doors from opening simultaneously), stainless steel 304/316 construction, and easy-to-clean smooth surfaces without active airflow.
• Dynamic Pass Boxes (Air Shower Pass Box):
  • Best for: Transferring materials from a lower cleanliness area to a higher cleanliness cleanroom (e.g., ISO Class 8 to ISO Class 5/6), especially in pharmaceutical, laboratory, and biotech applications.
  • Key Features: Built-in HEPA filters (99.99% efficiency at 0.3μm), high-velocity air nozzles creating a self-cleaning air shower effect, differential pressure gauges, and intelligent PLC control systems.

3. Critical Factors for B2B Buyers When Sourcing Pass Boxes

When requesting quotes or customizing pass boxes for industrial cleanroom projects, engineering and procurement teams should evaluate the following specifications:

• Material & Construction: Opt for SUS304 or SUS316 stainless steel with polished or hairline finishes to resist chemical sanitization (hydrogen peroxide, isopropyl alcohol).
• Interlocking Mechanism: Ensure reliable electronic or mechanical interlocking to eliminate air bypass and pressure loss.
• Filtration & Airflow Velocity: For dynamic models, verify HEPA filter replacement accessibility and air velocity (typically 20-25 m/s at the nozzle).
• Custom Dimensions: Standard sizes range from 500x500x500mm up to large cart-pass sizes, tailored to your specific material handling containers.

4. Why Partner with Farclean for Cleanroom Pass Box Solutions?

At Farclean, we engineer high-performance cleanroom equipment tailored to global GMP and ISO standards. Our pass boxes are designed for maximum durability, airtight sealing, and seamless integration into modular cleanroom wall panels. Whether you need standard static units or custom dynamic air shower pass boxes with interlocking electrical systems, our engineering team delivers reliable, factory-direct solutions.