In recent years, the demand for clean room design and construction of clean rooms has increased. Due to the requirements of high-tech products such as computer manufacturing, chip manufacturing, circuit boards, semiconductor technology ... or drugs in pharmaceuticals, medical equipment, and operating rooms in hospitals. All of these rooms require control of temperature, humidity, air flow, dust and dust contamination ... to an acceptable level and are called clean rooms.
For clean rooms usually solve five main problems are temperature (temperature), humidity (humidity), room pressure (Room Pressurization), cleanliness (Cleanliness) and cross-contamination problem. In the design of normal air-conditioning, it only solves two main problems: temperature and humidity, in fact, the problem of humidity often does not meet the design requirements. But in a clean room, in addition to temperature, the humidity in the room is much stricter.
The main differences between a clean room and a normal air conditioner are:
1. Room Pressurization:
The main task is to prevent air, dust, and infectious substances ... from getting from a room, a dirty area to a cleaner room or area. The basic principle of air movement is from high pressure to low pressure. Thus the room with the cleaner grade has higher pressure and vice versa. To control room pressure, there is usually a pressure gauge, when the room is exceeded, it will automatically overflow through the exhaust (Pass-Through Grilles). Usually, the rooms with high requirements are fitted with air vents. blow. The pressurization in the room when designing must consider the fan head and the difference between the supply and return air wages in the clean room. In the design of a pharmaceutical factory according to WHO-GMP (World Health Organization-Good Manufacturing Practice) standards, the pressure levels are + (15Pa), ++ (30Pa), +++ (45Pa), respectively.
2. Cleanliness (Cleanliness):
Room cleanliness is usually determined by two factors: the number of air changes or the number of cycles (Air Changes per Hour) and the Air Filter. Normally for air conditioning for office buildings can be from 2 to 10 times. But in a clean room, the number of wind exchanges is up to 20 times, especially in a clean room for chip production up to 100 times. Increase the number of air exchanges to reduce the concentration of dust, pollutants in the room. So clean room structures are different from office buildings. With rooms with different levels of cleanliness, the number of air exchanges is also different. For example, in a pharmaceutical manufacturing plant that the dressing area has an E grade (black grade) with a room pressure of + (15Pa), the number of air exchanges is 10, while the dispensing room has a grade C with room + ++ (30Pa), air exchange rate is 20, filter grade H12. The filter is responsible for filtering out the dust particles of the air before entering the room. Depending on the requirements of all types of clean rooms that use filters accordingly. Normally, with the rooms in the pharmaceutical factory, they should use high efficiency filter HEPA (High Efficiency Particle Air). The filter position can be mounted at the AHU or each room.
Figure HEPA filter
In order to understand cross-contamination, we define contaminants: contamination is the undesirable (introduction) contamination of impurities of chemical or microbial nature, or foreign particles into or on a starting material or intermediate product during manufacturing, sampling, packaging, storage and transport.
Thus cross-contamination is the adulteration of a starting material, intermediate product, or finished product with another starting material or product during production. Cross-contamination has both external and internal causes. Below is a summary of the main factors for cross-contamination in pharmaceutical plants.
Cross-contamination problem is quite complicated for pharmaceutical factory rooms as well as operating rooms in hospitals. The clean rooms for high technology are much less than producing one product in a large area.
In fact, Vietnamese pharmaceutical factories produce so many different drugs in the same room that a very high level of cleanliness is required and the problem of cross-contamination becomes difficult to control. The solution to cross-contamination is to solve the above 10 problems, to add pressure to the room