𝗛𝗼𝘄 𝗱𝗼𝗲𝘀 𝗮𝗻 𝗔𝗶𝗿 𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴 𝗨𝗻𝗶𝘁 (𝗔𝗛𝗨) 𝘄𝗼𝗿𝗸 𝗶𝗻 𝘁𝗵𝗲 𝗽𝗵𝗮𝗿𝗺𝗮𝗰𝗲𝘂𝘁𝗶𝗰𝗮𝗹 𝗶𝗻𝗱𝘂𝘀𝘁𝗿𝘆?

𝗛𝗼𝘄 𝗱𝗼𝗲𝘀 𝗮𝗻 𝗔𝗶𝗿 𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴 𝗨𝗻𝗶𝘁 (𝗔𝗛𝗨) 𝘄𝗼𝗿𝗸 𝗶𝗻 𝘁𝗵𝗲 𝗽𝗵𝗮𝗿𝗺𝗮𝗰𝗲𝘂𝘁𝗶𝗰𝗮𝗹 𝗶𝗻𝗱𝘂𝘀𝘁𝗿𝘆?

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.

Conclusion:
In the pharmaceutical industry, the required percentage of fresh air in the returned air of an AHU system is typically very high, often exceeding 90%. This stringent requirement is essential for maintaining product quality, safety, and regulatory compliance. By carefully considering these factors and consulting with qualified HVAC professionals, pharmaceutical manufacturers can ensure that their AHU systems meet the necessary standards for a controlled and safe manufacturing environment.