Air conditioning system design of 100-level clean area in pharmaceutical workshop in clean room

2019-02-16 10:42:26   Editor:    0

In the clean area of the pharmaceutical workshop, there are often local 100-level zones, or a room inside is required to be a hundred-level, which is usually part of a process line in a clean zone, but they all play an important role in the clean room. . For example, filling, dispensing, and tamping of sterile pharmaceutical injections, especially in non-terminally sterilized sterile aliquot injections, sterile lyophilized powder injections. Whether the 100-level zone can operate normally will directly affect the product quality. The environmental protection of the 100-level district is relatively high, and the noise requirements are high (the “clean factory design code” requires ≤65 dB). In addition, there are more air ducts around the ceiling of the 100-level area, and the space above the ceiling is limited.


The production level of the 100-level area of the clean factory of the pharmaceutical factory is mainly the filling of the liquid preparation soft bag large infusion, the filling of the glass bottle large infusion unit and the filling area of the plastic bottle large infusion coupling group, and the hundred-level laminar flow is set in this area. In order to ensure the quality of the products, at the beginning of the design, through the comparison of different air-conditioning system schemes in the 100-level area, a hundred-level air-conditioning method suitable for the filling area is adopted.


2. Hundred-level zone circulating air treatment


 The 100-level zone of the pharmaceutical workshop is usually vertical laminar flow, and the wind speed of the section is controlled at 0.25-0. 3 is too much waste. Too small a waste should not be guaranteed. The general practice of circulating air treatment in the 100-level area of the pharmaceutical workshop is as follows:


The scheme (1) is full of FFU fan purifying unit above the 100-level area. The FFU itself has both high-efficiency filters and circulating fans. The top return air (or side return air) is used to supply air to purify the home gas in the 100-level area. Independent cycle, see Figure 1. In this way, the circulating air pressure filtration is completed by the FFU, the treatment method is relatively simple, the air conditioning system layout is compact and flexible, and the construction is relatively simple. Due to the independent circulation of the laminar flow, the air volume is determined according to the number of FFUs assembled in the 100-level zone. The air supply volume and fresh air volume of the room are calculated according to the room purification requirements. Since the FFU in the 100-level zone is an independent cycle, the influence of the large air-conditioning system in the clean zone is small. When the daily process layout is adjusted in a small range, it is only necessary to adjust the FFU layout, and the air conditioning of the remaining clean areas is not greatly affected.


  

In this case, the FFU is arranged with a certain return air distance between the top and the ceiling, and an antistatic plastic block is placed at the boundary of the 100-level zone. Generally, the height of the clean zone is 2. 6m. When assembling a hundred-level laminar flow hood, the height of the ceiling should be raised to meet the requirements of the process operation; the advantages of this scheme are as follows: Firstly, because the purification unit is assembled in the interior of the room, the start-stop switching will not affect the air volume of the large system, and secondly According to the process layout adjustment, the assembly position is changed, which is more flexible. Thirdly, the lifting height can be changed according to the operation requirements, and the laminar flow area is closer to the process console, and the airflow effect is better. Of course, this method also has its shortcomings: firstly, the fan purification unit itself has a certain height. If the side air inlets are blocked when assembling multiple units, only the upper air inlet can be used. In this case, the air inlet spacing of the air outlets should be considered during installation. Generally speaking, the process operation area cannot be too low. If the height of the laminar flow area does not meet the requirements of the process operation, the ceiling of the area needs to be raised, which affects the layout of other professional equipment to a certain extent. In addition, since a plurality of fan purifying units are directly assembled in the lower part of the ceiling, the problem is that the noise is too large, the fan dissipates too much, and the overall cost is too large. However, in recent years, the FFU manufacturing technology has improved, the FFU single-machine cost and noise have been declining, and the fan efficiency has been continuously improved. At present, the noise of single-machine FFU products is between 52 and 57 d B (A). This method is ideal for small areas, but when the 100-level area is large, the number of FFUs is large, dozens or even more. The noise in the 100-level area is difficult to meet the specification requirements, and the cost is also high. This method is not recommended.


Scheme (2) A static pressure box is arranged in the upper part of the 100-level area. The ceiling of the 100-level area is covered with the FFU fan purification unit. The circulating air enters the return air duct from the lower air return port of the clamp wall of the 100-level area, and is connected to the static pressure box through the air duct. It is sent into the room through the FFU, see Figure 2. In this way, the circulating air pressure filtration is completed by the FFU, and the treatment method is relatively simple, and the circulating air treatment can be completed in the ceiling of the 100-level zone. Of course, this kind of solution also has its own shortcomings. When the laminar flow area is too large, the number of FFUs is too large, which makes the assembly of the equipment difficult, and affects the layout of other professional equipment to a certain extent.


Scheme (3) There is a static pressure box on the top of the 100-level area. The ceiling is covered with high-efficiency filter. The air is pressurized by a single circulating fan. The air is returned from the back air of the 100-level area, and then pressurized and sent to the static pressure box. It is sent into the room through a ceiling high efficiency filter, see Figure 3.

             

The method has the following advantages: 1_100-level area cost is lower than FFU system; 2. Can better control the noise of the circulating air system. The 100-level area of the pharmaceutical workshop is small. In the actual project, multiple circulating fans can be used to pressurize, and the total pressure of the control circulating fan is within 450Pa. In this way, the use of a small power fan to reduce the noise of the fan itself, and the installation of a muffler on the fan inlet and outlet ducts, can effectively control the noise of the hundred-level zone. The disadvantage of this method is that it is necessary to set up a circulating air chassis and handle noise, and a large space is required. Generally, the air ducts around the 100-level area are relatively dense and need to be carefully arranged. In this way, the upper static pressure box of the 100-level area is positive pressure relative to the indoor area of the 100-level area, and the ceiling high-efficiency filter and the hanger are leaked. The static pressure box flows into the room, which directly affects the cleanliness of the 100-level area, and has high construction requirements. .


3. Hundred-level zone circulating wind return mode


The circulating air return mode of the 100-level area can be returned to the wind by the grille floor and the return air of the lower part of the side wall. The airflow in the lower part of the grille has a good vertical airflow effect, but it needs to be provided with a return air static pressure box under the grille return air floor (about 500mm high, which can be adjusted according to the actual case). However, in actual engineering, because of the influence of this method on the surrounding clean area, the cost is too high, and the general project is rarely used. The 100-level area of the pharmaceutical workshop is small. The reasonable arrangement of the return air outlet can generally meet the vertical laminar flow requirements of the 100-level airflow, which is convenient for construction and low in cost. If the room is large, a return air shaft can be added in the center of the room, and a return air outlet is arranged around the shaft to reduce the distance between the air return ports on the side wall of the room.


Due to the characteristics of the process equipment in the 100-level area, the 100-level area often has a process line that passes through, and communicates with other clean areas. The process line runs through the wall with holes. Generally, it is required to calculate the leak through the hole according to the room pressure difference and the tuyere wind speed. The positive pressure air volume reduces the amount of return air in the room. The proper calculation of the air volume here will greatly affect the differential pressure debugging of the room in the future operation, and this effect is reflected in some rooms with higher pressure index. .


4 hundred district air conditioning temperature and humidity control


The 10,000-class clean workshop contains a local area of 100, which is more common in the clean area of the pharmaceutical workshop. In this case, the local hundred-level area is small. You can use the 10,000-level purification air-conditioning system to control the indoor temperature and humidity and supplement the fresh air. Increase the circulating air volume in the local 100-level zone. The circulating air treatment method can adopt the aforementioned method.


5. Practical engineering application


The 100-level clean area in a pharmaceutical factory's clean system has the following characteristics: There are many areas, and some of the 100-level process equipment belongs to high-temperature equipment (using steam and electric heating). The heat dissipation is large, and the process equipment is operated in three shifts all year round. According to the previous design experience and the feedback from the technicians of Party A on the past engineering results, it is found that in this case, the indoor temperature of the winter and transition seasons is higher in this area. Although the number of air changes has increased correspondingly, the internal temperature of the room is still relatively high. High, to a certain extent, affect the efficiency of staff. The reason for the analysis is that since the 100-level zone is located in the center of the clean plant, the annual temperature changes are not large, and the indoor temperature is simply treated by a large system. In the winter and transitional seasons, when other clean rooms need to be heated, the area needs to be cooled. At this time, the chiller has generally stopped running, and the cooling demand in this area is small. Considering the control, maintenance and cost of the system, It is not advisable to add an independent air conditioning system to a local 100-level area. In order to solve the problem of external heat inside, the bypass treatment is adopted, that is, a wind pipe is connected to the total air supply pipe of the room to be connected to a purification type direct evaporative hanging air conditioner. The electric valve is opened and closed on the two branch pipes, and the electrical interlock is shown in Figure 4.


       

This type of air handler has a small cooling capacity and a small amount of air. The cold source is an independent cold source, which is convenient for control and maintenance, and meets the requirements for use in this area. Excessive seasons and winter refrigerators are not turned on. When the indoor temperature exceeds the required temperature, the air handler is turned on to cool the air in the local area, and the cleaned air that has been cooled is sent to the room through the original air outlet. The circulating air treatment adopts the (1) scheme, that is, the FFU fan purifying unit is assembled under the indoor ceiling, and the 100-level zone is independently cycled. The room air supply is sent by the high-efficiency air outlet located outside the 100-level zone, and the air supply meets the fresh air requirement of the clean zone. .


If there is no high-temperature equipment, if the conditions permit, then the (3) scheme is adopted, that is, the top of the 100-level clean area is covered with a hundred-layer laminar flow hood, and the static pressure box is placed above the laminar flow hood. The return air is connected to the circulating fan through the return air vertical pipe, and is sent to the static pressure box through the pressure filtration. The air volume of the fan is calculated according to the air flow rate of the laminar flow hood. The total pressure of the fan is 450 Pa. Because of the noise requirement in the clean area, the fan enters. A purifying muffler is installed at the exit.


6. Conclusion


By comparing the air-conditioning modes of the 100-level district in the clean area of the pharmaceutical factory, it is considered that the air circulation mode in the 100-level clean area needs to closely match the requirements of the professional use of the process. The local area air-conditioning load needs to consider the heat dissipation at different stages of the process equipment, and Considering the particularity of such areas during the transitional season and winter, different treatments are used to treat the air supply to provide better indoor air quality in the clean room.


references


1 Implementation Guide for Quality Control of Pharmaceutical Production (GMP) (2001 Edition)


2 Clean factory design specifications (GB50073-2001)


3 Heating Ventilation and Air Conditioning Design Specification (GB50019-2003)


4 Ventilation and air conditioning engineering construction quality acceptance specifications (GB50243-2002)


5 Clean room construction acceptance and inspection specifications (JGJ71-90)