The first issue is the problem of layout, which is particularly significant in the design of pharmaceutical cleanrooms and biosafety laboratories. The main challenge lies in the complexity of the floor plan. In pharmaceutical factory design, it's essential to ensure that clean areas remain uncontaminated, with clear zoning, separation, and distinct pathways for personnel and logistics. However, overcorrection often occurs due to a lack of professional understanding by some industry authorities when setting acceptance criteria. This leads to overly complicated layouts, especially in buffer zones, causing unnecessary operational difficulties.
For example, when China Southern Purification Company designed a pharmaceutical factory, the workflow involved multiple steps: changing shoes, entering a buffer room, washing hands, disinfecting, and then proceeding through several more buffer areas before reaching the high-level cleanroom. This meant staff had to pass through nine rooms and open/close 18 doors, making the process extremely cumbersome. Additionally, many small-scale pharmaceutical companies have limited space, resulting in auxiliary rooms as small as 2 square meters, where even two people struggle to move comfortably. The tight spaces make door operations difficult and increase the risk of accidents.
While strict requirements are important, overcomplication can be counterproductive. Many workers end up closing multiple doors just to access a single area, leading to inefficient use of space. A better approach is to merge unnecessary rooms and eliminate those that don't add value. For instance, hand sanitization areas can double as buffer zones, and buffer chambers between 10,000 and 100,000-class cleanrooms may not always be necessary. The primary purpose of buffer rooms is to isolate airflow by using two doors, and in some cases, existing auxiliary rooms can serve this function effectively.
Another common misconception is the need for buffer zones between 100,000 and 10,000-class rooms. In reality, the difference in dust concentration is not as drastic as some non-experts assume. According to the Veterinary Drug GMP (2002), the minimum air exchange rate for a 100,000-class room is 15 times per hour, while for a 10,000-class room, it's 20 times. For small rooms, the actual impact is minimal, and in practice, there’s little difference in cleanliness levels. Therefore, unnecessary buffers only complicate the layout without adding real value.
This same issue has also appeared in the construction of three-level biosafety laboratories. Some authorities require strict separation of people, logistics, waste, and dirt, but such rigid configurations are often impractical and unnecessary. Policies that emphasize "biosecurity cannot be overemphasized" may stem from a lack of technical knowledge rather than genuine concern. In reality, practicality, safety, and cost-efficiency should guide the design. For example, some countries use simpler layouts like "two districts and one slowdown," while others impose overly complex structures like "three districts and two mitigations." These designs are hard to implement and maintain, especially under negative pressure conditions, making them less feasible for real-world applications.
A major issue in biological cleanroom construction is the use of rounded corners. While they are intended to reduce dead spaces and improve cleanliness, poor execution often leads to problems. JGJ 71-90 specifies that skirting boards should be flush or slightly recessed, with rounded corners of at least 50mm radius. However, many projects use aluminum fillets that are poorly installed, creating gaps where bacteria can accumulate. These issues become apparent during cleaning, as water can seep into adjacent areas, promoting microbial growth. To address this, alternatives like self-flowing floors or integrated coiled flooring can be used to eliminate joints and improve hygiene.
Terrazzo floors are commonly used in low-grade cleanrooms due to their durability and cost-effectiveness. However, some projects experience high dust levels, especially with particles ≥5μm exceeding limits. This is often due to the use of low-quality cement or improper finishing. According to JGJ 71-90, cement grades should not be lower than 425, and pebbles should be 6–15mm in diameter. Proper sealing with non-volatile materials is also crucial. While terrazzo can be an effective option, substandard workmanship can undermine its performance.
In conclusion, designing biological cleanrooms requires a deep understanding of different requirements and regulations. Overcomplication, lack of practicality, and poor execution can lead to inefficiencies and safety risks. By focusing on real-world needs and following best practices, cleanrooms can be both functional and compliant. This article is organized by professional purification engineering, purification equipment, and air filter experts in China Southern.
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