Letzter Unternehmensfall über Guangzhou Cleanroom Construction Co., Ltd. Zertifizierungen

In cleanroom HVAC systems, the selection of FFUs (Fan Filter Units) and HEPA filters directly affects the cleanliness level, airflow distribution, energy efficiency, and long-term operational stability. Proper sizing ensures the cleanroom meets its required classification while maintaining system performance and operational reliability.

1. Key Principles for Selecting FFUs

1.1 Coverage Ratio Based on Cleanroom Classification

Different ISO classes require different airflow and supply coverage levels. The following ratios are commonly used in industry practice:

Coverage may be adjusted according to process requirements and airflow uniformity.

1.2 FFU Size Selection

Common FFU dimensions include:

1175 × 575 mm (4×2 ft)

1175 × 1175 mm (4×4 ft)

575 × 575 mm (2×2 ft)

Selection depends on ceiling grid type, layout, equipment spacing, and maintenance access.

1.3 Critical Performance Parameters

Important criteria include:

Rated airflow

Energy consumption (EC motors offer better efficiency)

Noise level

Air velocity stability

Compatibility with HEPA filters

These factors influence comfort, system efficiency, and service life.

2. Key Principles for Selecting HEPA Filters

2.1 Filtration Efficiency Levels

HEPA filters must be selected according to the required cleanliness standard:

The required grade depends on process sensitivity and regulatory requirements.

2.2 Dimensional Matching

HEPA filter size must match the FFU dimensions, typically:

1175 × 575 mm

1175 × 1175 mm

575 × 575 mm

Proper sealing is essential to avoid leakage.

2.3 Technical Considerations

Include:

Factory leak test according to EN 1822

Filter media type (glass fiber or PTFE)

Initial and operating resistance

Sealant and frame materials

These factors determine filtration performance and lifespan.

3. System-Level Design Recommendations

When integrating FFUs and HEPA filters into a cleanroom HVAC system, the following factors should be evaluated:

3.1 Air Change Rate

ACH requirements differ among ISO classes and influence the number of FFUs needed.

3.2 Airflow Design

Includes:

Vertical unidirectional flow (common for ISO 5/6)

Full-ceiling laminar flow layouts

Localized high-cleanliness zones

This determines FFU layout, spacing, and quantity.

3.3 Energy Performance

Selecting low-resistance HEPA filters and high-efficiency FFUs helps reduce operational energy consumption.

4. Conclusion

Proper sizing of FFUs and HEPA filters is essential to achieving stable cleanroom performance. By determining the required cleanliness level, optimizing coverage ratios, selecting appropriate dimensions, and ensuring filter quality, cleanroom systems can maintain reliable airflow, efficiency, and long-term functionality.