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An AHU plays a critical role in maintaining cleanroom conditions, controlling particulate contamination, and ensuring compliance with regulatory requirements (USFDA, EU GMP)
1. Air Intake and Pre-Filtration
Fresh air Intake: The AHU draws in fresh air and passes it through pre-filters (10-micron filters) to remove larger dust particles.
Return Air: Air from the controlled environment is also recirculated and passes through return air dampers (RAD). This maintains air exchange rates and optimizes energy efficiency.
2. Combination Filters
The pre-filtered air is passed through a combination of filters 5 and 10-micron (90% efficiency filters) to further remove finer particles, ensuring the air quality improves progressively.
3. Chiller Coils and Moisture Elimination
The air is then cooled by chiller coils to reduce its temperature, typically down to 10°C.
The cooled air passes through a mist eliminator, which removes moisture and prevents condensation-related issues in the cleanroom.
4. Heating Coils for RH Control
To maintain the relative humidity (RH) within the desired range, heating coils are used to warm the air slightly. Precise RH control is essential to prevent microbial growth and product degradation.
5. HEPA Filtration
The air then passes through HEPA filters (0.3-micron filters) with 95% efficiency. These filters remove almost all remaining particles, ensuring ultra-clean air suitable for pharmaceutical manufacturing areas.
6. Air Supply to the Cleanroom
The filtered air is distributed through ducts and supplied to the cleanroom or controlled area SG HEPA filters (0.3-micron filters) with 99.99% efficiency. Positive pressure is maintained to prevent contamination from entering.
7. Air Return
The return air, along with a small percentage of fresh air 10%, is recirculated. This ensures energy efficiency while maintaining compliance with air quality standards.
