Cleanroom facilities are fundamental to ensuring the quality of biopharmaceutical products and preventing contamination. Newly constructed cleanroom require a two-stage process: completion acceptance and comprehensive performance evaluation, conducted by a qualified third-party institution. Cleanroom already in use require regular performance testing to ensure compliance with relevant standards. The following are seven key considerations in the design process.
I. Over-specification in Cleanroom Design and Construction
Some companies design and construct multiple cleanroom of different grades (from Class 10,000 to Class 300,000) according to a single Class 10,000 standard. While this simplifies the process, it leads to waste. Some oral solid dosage form workshops, which only require Class 300,000, are designed to Class 100,000 standards, and the cleanroom area and height exceed requirements. Except for special process workshops such as extraction and drying rooms, the cleanroom height should be controlled between 2.6 and 3.0 meters. The grade and height should be determined based on process requirements, using a design with localized high-grade areas and overall lower-grade areas to reduce initial investment and operating costs.
II. Unreasonable Air Change Rate in Cleanroom
Air change rate, pressure difference, and suspended particle count are the three core requirements for cleanroom. The dilution and displacement effects of cleanroom depend on the amount of clean air, so the air change rate should not be too low; otherwise, it cannot guarantee that the cleanliness parameters meet the standards.
III. Top-Supply and Top-Return Airflow Method is Not Recommended
Although the top-supply and top-return method is inexpensive, it has significant drawbacks: the concentration of 5μm large particles in the breathing zone exceeds the standard, the airflow velocity in localized Class 100 working areas is insufficient, and the self-purification time is doubled. While it may meet standards under static conditions, it is not conducive to removing contamination under dynamic conditions and is therefore not recommended.
IV. Problems with Localized Class 100 Areas
Some companies experience a decrease in product clarity and an increase in defective rates after installing localized Class 100 areas. The main reasons include: substandard HEPA filters that were not individually tested; improper installation, leading to looseness due to the lack of rubber gaskets; insufficient unidirectional airflow velocity, preventing timely removal of contamination; unreasonable design of air supply outlets, where non-unidirectional airflow outlets interfere with local airflow; and production personnel not strictly adhering to cleanroom work procedures.
V. Unreasonable Layout of Cleanroom Facilities
The facility layout does not consider airflow patterns and their impact on cleanliness: Non-unidirectional flow cleanroom only have return air vents on one side, increasing the risk of eddy currents and cross-contamination; return air vents are not located far from the work area; process equipment requiring exhaust and pressure relief valves are not positioned on the downstream side of the clean airflow, affecting the removal of pollutants.
VI. Insufficient Number of Supply Air Outlets
Due to site conditions or investment constraints, some designs excessively reduce the number of supply air outlets, leading to increased air velocity at the same air change rate, uneven velocity distribution, and increased or expanded eddy current areas, affecting the cleaning effect.
VII. Unreasonable Selection of Filters
Filter selection should follow three principles: the final filter must have reliable performance, the pre-filter efficiency specifications must be reasonable, and the primary and pre-filter must be easy to maintain; high-efficiency filters must be inspected individually. Prioritizing filters with larger filter media area can increase dust holding capacity and service life, reducing airflow resistance, maintenance costs, and air conditioning energy consumption.
Suzhou Pharma Machinery Co.,Ltd.
2026/05/08
Icey
