reatment of circulating air in FFU 100 level working area of pharmaceutical factory

Finally, it is sent into the room by FFU. In this process, the FFU itself has a high-efficiency filter and a fan, so the pressure filtration work of the circulating air is completed by the FFU, and the overall treatment is relatively simple, only need to complete the processing process of the circulating air in the suspended ceiling of the hundred level area.
This setting makes the layout of the air conditioning system more compact and convenient, and the construction is relatively simple. Moreover, the plenum in the upper part of the 100-level area presents a negative pressure state relative to the 100-level area, even if there is leakage between the FFU and the hanger in the 100-level area, it is also the indoor airflow to the plenum, which has a relatively small impact on the cleanliness of the 100 level area.
In recent years, with the continuous improvement of FFU manufacturing technology, the cost of FFU fans has gradually decreased, the noise generated is also continuously reducing, and the efficiency of the fan is still steadily improving, so the way of FFU treatment of circulating air in the hundred level area of the pharmaceutical dust-free workshop is becoming more and more common. However, it should also be noted that the current single-unit noise of FFU products is mostly between 52 and 57dB (A), and if the number of FFU used in the hundred-level area is larger, reaching dozens or even more, the noise in the hundred level area may be difficult to meet the requirements of the specification, and the overall cost will be relatively high.
(2) Other circulating air treatment methods and comparison
In addition to the circulating air treatment method of full FFU, there are other ways to choose. For example, a plenum is set at the upper part of the hundred-level area, and the ceiling is full of high-efficiency filters (full rate should be ≥65%), and then the circulation fan is used to let the circulating air enter the air from the vertical air duct of the hundred level area, and is fed into the plenum after pressure, and then through the ceiling high-efficiency filter, and finally into the room.
This method has its unique advantages, first, the cost of the hundred-level area is lower than the FFU system; Second, it can better control the noise generated by the circulating air system. Usually, the area of the 100-level clean area of the pharmaceutical clean workshop is relatively small, and the circulation air volume is mostly within 50000m³/h (to ensure the 100-level area of 50m²). In the actual project, multiple circulation fans can be used to pressurize the circulation fan, the total pressure of the circulation fan can be controlled within 420Pa, and the noise of the fan can be reduced by using low-power fans. By installing mufflers on the inlet and outlet pipes of the fan, the noise in the 100-level area is effectively controlled.
However, there are also some shortcomings in this way, it needs to set up a circulating fan box to deal with noise, so it needs a larger space, and the general air duct around the 100-level area is often dense, which requires careful layout planning. In addition, under this method, the upper plenum of the 100-level area is relatively positive pressure, and the leakage between the ceiling high-efficiency filter and the hanger flows from the plenum to the room, which will directly affect the cleanliness of the 100-level area, and the requirements for construction quality are also relatively high.
Compared with the way of full FFU, in terms of cost, the cost of full FFU will be high when the number of FFU is large, and the cost of the above method using a circulating fan is relatively low; In terms of noise control, it is difficult to control the noise to meet the standard when a large number of FFU is used, and the circulation fan can control the noise better through relevant measures. For the influence of cleanliness, the full FFU method has a small impact on cleanliness because the plenum is negative pressure, and the circulation fan method has a direct impact on cleanliness because the plenum is positive pressure. Therefore, when choosing a circulating air treatment method, pharmaceutical manufacturers need to consider their actual situation, budget, and requirements for cleanliness and noise to determine the most suitable program.