News - What are the common problems with purified air conditioning systems in pharmaceutical plants?

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What are the common problems with purified air conditioning systems in pharmaceutical plants?

What are the common problems with purified air conditioning systems in pharmaceutical plants? System selection The purification air conditioning system is the key equipment to ensure the pharmaceutical production environment. In actual operation, the pre-defined air conditioning system is unreasonable, resulting in the risk of cross-contamination in pharmaceutical production, large fluctuations in room temperature and humidity, difficulties in system adjustment, high energy consumption, and high renovation and maintenance costs, resulting in a pharmaceutical production environment that does not meet the requirements of pharmaceutical production management regulations and poses a risk to pharmaceutical quality. Therefore, the above situation should be fully considered when designing the purification air conditioning system, and to reduce and avoid similar situations. The basic basis and principles for the division of air conditioning and purification systems in pharmaceutical manufacturing enterprises are ①Divide according to the category of the product to avoid the risk of cross-contamination. ②By the pharmaceutical production environment (clean level), rooms of different clean levels should be divided into different air-conditioning systems for control. ③Separate air conditioning systems according to the base (e.g. 18 to 26°C, 45% to 60%) and accuracy (e.g. ± 0.5°C, ± 5%) of the room temperature and humidity. ④Dividing the air conditioning system according to space (room orientation, floor) location, etc., facilitates the layout and installation of air ducts and facilitates later operation and management. ⑤Dividing the air conditioning system according to the hazards of toxic and harmful substances and dust concentration to avoid cross-contamination and improve the life of medium and high-efficiency filters. ⑥Dividing the air conditioning system according to the operating hours and shifts of the air conditioner, to facilitate the economy of operation. ⑦According to the room airflow flow form ( laminar flow, turbulent flow) of a different division of the air conditioning system. ⑧Room humidity and heat load changes, and the temperature and humidity in the region need to be strictly controlled room should be partitioned set system, or set up a local treatment device (reheat system, partition unit system, etc.). ⑨For the sake of operation and maintenance convenience, large air volume air conditioning systems should be divided into different small systems according to the actual situation, generally ≤ 40000m3/h air volume is appropriate. ⑩According to the requirements of the fire partition, the partition of the air-conditioning system should meet the requirements of the fire partition of its building. Air volume selection In addition to meeting the temperature and humidity requirements of a clean room and preventing the outside air from polluting the cleanliness of the room, the air supply volume of the purified air conditioning system also needs to replace and dilute the pollutants in the indoor air, maintain the cleanliness level of the environment and ensure a reasonable airflow direction. In the actual operation of the air conditioning system, there is insufficient room air volume resulting in poor cleanliness and too high room air volume resulting in increased energy consumption, resulting in difficulties in balancing air volume during system commissioning, and poor system stability during operation. Therefore, in the purification air conditioning unit system selection, procurement should reasonably consider the air supply volume of the air conditioning system fan; the system's normal operation of regular monitoring of the change in air volume, to prevent the air supply volume from reducing the impact of clean room cleanliness. Key points of air conditioning fan selection 1)The total air supply volume of the fan should meet the air volume required for the minimum number of air changes in each room (the number of volume flow changes in the room in 1h). Usually based on the cleanliness level of the room and the typical values of engineering rules of thumb to estimate the total air supply: FDA and ISPE CNC (EU D dynamic standard) level space, 6 to 20 times/h; ISO8 (EU C dynamic standard) space, 20 to 40 times/h; ISO7 (EU B dynamic standard) space, 40 to 60 times/h; ISO5 (EU A level) space. For unidirectional flow, the number of air changes is not relevant; the speed and form of the airflow are crucial. 2)A comprehensive consideration of the minimum airflow required to meet the room's dehumidification heat source. This usually includes the following. ① The air volume required to remove the incremental heat generated by room equipment and personnel activities; ② the air volume required to remove the incremental moisture heat generated by cleaning activities. ③ the different air volumes required due to differences in air delivery methods and efficiency. ④ the different air volumes required for the different dressing of the operators (clean clothing or isolation suits). ⑤ different processes and their particle generation rates, resulting in more air volume being required for power units. ⑥Different air volumes are required for different ways and locations of room exhaust. 3) The air volume required to achieve the required differential pressure, which is usually less than that required by 1) and 2). 4) Choose a direct fan connection as far as possible to reduce belt maintenance; choose a fan frequency converter for energy saving and economic operation. The common situation and treatment method of air supply volume reduction 1) The fan belt is worn and slippery, resulting in a reduction in fan output; replace the worn belt and tighten the belt tension. 2)The soft connection between the air duct and the static pressure box is broken and leaking; repair and replace the soft connection. 3) Air leakage at the interface of the air supply line; glass glue seal or reconnect the air leakage gasket. 4) Clogged primary and secondary air filters, insufficient air supply; monitor the pressure difference between the front and rear of the filter and replace the filter in time. 5) High-efficiency filter blockage, wind can not be sent; regular detection of air volume and differential pressure at the air outlet, according to the use of the situation to determine a reasonable replacement cycle. 6) Clogging of the system return air and exhaust air filters, resulting in high air pressure in the room and no air being sent out; regularly clean and replace the filters. 7) The position of the air supply valve changes during operation, resulting in the valve closing and not being able to send air; after the commissioning of the air volume, lock and fix the valve opening, affix the position mark, and conduct regular inspection. Contaminant control Depending on the process and properties of a pharmaceutical product, it needs to be produced in areas with different levels of cleanliness. The relevant domestic and international regulations governing the production of pharmaceuticals have specific provisions on the number of suspended particles in the production environment of pharmaceuticals in their respective quality management documents. The factors affecting the cleanliness of a clean room are made up of two components: exogenous and endogenous contaminants. Exogenous contaminants include the introduction of air into the cleanroom and the infiltration of contaminants into the cleanroom envelope. Endogenous contaminants include dust generated by the workforce and dust generated during the production of equipment and products. Control of dust particle contamination is an important function of a clean air conditioning system to ensure the purity, uniformity, and quality of pharmaceutical products. Inadequate maintenance and management of the HVAC system can lead to production stoppages and drug rejects, and should be taken seriously by HVAC maintenance and management staff. Control measures for clean room contaminants are as follows. ①Air-conditioning primary and secondary filters are regularly cleaned or replaced, and chassis or air supply ducts should be cleaned regularly. ②High efficiency filters are regularly tested for leakage rate, and the air volume is reduced or broken and replaced in time. ③The doors and windows of the clean room, the walls, floors, and roof gaps should be sealed, and the connections of the pipelines in and out of the clean room should be sealed to prevent exogenous sources of pollution from entering the clean room. ④Personnel in the clean room should wear suitable dust-free work clothes, standardize operations and reduce unnecessary movements. ⑤ Reduce the dust-producing aspects of the materials in the room and use closed production processes and equipment. ⑥Materials and items entering the clean room should be clean, using materials that are less likely to produce dust, and reducing unnecessary movement routes. ⑦ Regular cleaning of all types of equipment and facilities in the clean room to prevent the generation and retention of pollutants. Differential pressure control The differential pressure in a clean room is a certain static pressure difference between rooms of different cleanliness levels or between different clean rooms of the same level, the purpose of which is to protect the cleanliness of the clean room from the pollution of neighboring rooms when the normal work or air balance is temporarily disrupted. In the operation of purification and air conditioning systems in pharmaceutical companies, clean rooms are often subject to high or low differential pressures, large fluctuations, or even reversed airflow, bringing about quality risks in pharmaceutical production. According to years of experience analysis, the main influencing factors of clean room differential pressure lie in poor management and maintenance, as well as unreasonable system design and insufficient capital investment, resulting in poor stability of the differential pressure of the purified air conditioning system, which requires frequent adjustment of fan parameters, as well as air supply, air return, and air exhaust valves. The factors and countermeasures affecting the differential pressure in the clean room are as follows. 1) Changes in the air filter resistance of the purified air conditioning system, causing changes in the air supply, thus causing changes in the indoor differential pressure. Can regularly replace the primary, medium, and high-efficiency filters; or use variable frequency fan, to the actual air supply and set the difference between the air supply fan speed control, to ensure that the air supply is constant. 2) The opening and closing of the clean room door will cause fluctuations in the pressure difference of the clean room. Reduce the number of times the door is opened and closed and close the door by hand; set up a buffer room or airlock room; install a residual pressure valve and change the opening degree of the residual pressure valve by balancing the pressure block to achieve control of the clean room differential pressure. 3) Detect the pressure in the room through the differential pressure transmitter and control the opening degree of the air supply or return air valve to achieve control of the clean room pressure difference. 4) Excessive air leakage through the gaps in the doors and windows of the room causes the differential pressure to be too low. The enclosure structure and door seals can be regularly overhauled to ensure good air tightness. Temperature and relative humidity control In a clean room, if the temperature is too low, it does not facilitate the normal conduct of work; and if the temperature is too high, personnel sweating increase clean room pollution; and the temperature and relative humidity of materials sensitive to temperature and relative humidity, temperature and relative humidity need to be strictly controlled, otherwise, product quality can not be guaranteed. Therefore, ensuring that the clean room temperature and relative humidity are in line with the process requirements is an important ability of the air conditioning system. There are usually a variety of factors that cause the clean room air temperature and relative humidity not to meet the requirements, we should take different countermeasures. 1) Some pharmaceutical plants have a lot of heat-generating equipment and large, if only determined by the number of air changes, often lead to clean room temperature exceeding the standard. For example, through the fan filtration unit (FFU) to achieve an A-class purification area, you need to separately configure the air conditioning unit or use the air supply branch pipe secondary surface cooling (heating) method to control the room temperature. 2)There are problems with the design, installation, and commissioning of chilled water pipes, resulting in uneven flow distribution when using multiple sets of air-conditioning units in parallel, and difficulties in temperature and humidity control of air-conditioning units, which should be subject to pipeline transformation or water balance commissioning. 3) Equipment maintenance is not in place, resulting in purified air conditioning system operation, temperature, and relative humidity being out of range. For example, table cooler scaling, fin dust accumulation leading to low heat transfer efficiency, blocked pipelines leading to insufficient water flow, chilled water supply water temperature too high, steam supply pressure insufficient, steam condensate poor hydrophobic, etc., should strengthen the management and implementation of maintenance. Purified air conditioning unit design Improper design and selection of purified air conditioning units, which are equipped for cooling, heating, dehumidification, humidification, and purification through air purification and heat and moisture treatment, will cause great problems in the use of purified air conditioning systems. When making the selection and confirmation of the air conditioning unit, attention needs to be paid to the possible problems that may arise to reduce the trouble during the later commissioning and operation. 1) Insufficient space for maintenance. For example, the distance between the two sides of the table cooler and the two sides of the heater is insufficient, and in the case of heat exchanger maintenance, the box, and related parts need to be removed to repair. 2) Insufficient spacing between functional sections and no other remedial measures are taken, such as a short distance between the air supply section of the fan and the middle-effect filter section, and no even flow plate is added, resulting in extremely uneven air filtration speed across the entire section of the middle-effect filter at the fan outlet, affecting the filtration effect and shortening the service life of the filter. 3) The wind speed on the windward side of the box is larger, causing the condensation plate to drift after the table cooling section, and if the water baffle design is unreasonable, the problem will be more serious. Therefore, the wind speed on the windward side of the table cooler is controlled at 2~2.5m/s as far as possible during the selection. 4) The overall sealing performance of the unit is poor, such as when there is an air-conditioning unit power cable crossing the chassis, the sealing at the connection with the chassis plate is not strict, or even without any treatment. Therefore, in the unit acceptance of strict quality control. Usually, the standard requirement is that when the static pressure inside the purified air conditioning box is 1000 Pa, the air leakage rate inside the machine should not exceed 2%. 5) unit condensation system design is unreasonable, the water storage bend can not store water and condensation can not be discharged from the box, not only affect the air conditioning unit inside the surface but also affect the life of the filter, the heat and humidity treatment, and impact. Usually, the height of the condensate tray is greater than the negative static pressure of the unit (water column height) by 50%, the condensate pipe slope ≥ 0. 3%, the water seal height of the water storage bend is 2 times the maximum negative static pressure of the unit, the total height of the water storage bend is about 4 times the maximum negative static pressure of the unit. 6) The drainage port of the table cooler is unreasonably designed, and the stored water cannot be discharged cleanly, causing the table cooler to freeze and crack, making maintenance and replacement difficult. It is recommended that when using the air-conditioning unit in the north, after stopping the use of chilled water, disconnect the cold feed water inlet and outlet pipeline and blow the water stored in the table cooler with compressed air; if there is still some chilled water, the table cooler can be filled with an appropriate amount of glycol solution to prevent freezing. Energy-saving operation management In pharmaceutical manufacturing enterprises, the energy consumed by the operation of purification and air conditioning systems accounts for 20% to 30% of the energy consumption of the entire enterprise, which shows that energy saving in air conditioning is a very important task. Due to the lack of daily management and maintenance of air conditioning, there is a lot of hidden waste of energy in air conditioning. From the perspective of improving business performance, it is of great practical importance to achieve energy-efficient operation of air conditioning. The energy consumption of the HVAC system mainly depends on the determination of the air conditioning cooling and heat load and the reasonable operation parameters of the air conditioning system configuration, through good operation and maintenance management, can completely reduce the energy consumption of the purification and air conditioning system. 1) As the air volume and pressure loss of the air conditioning fan changes with the increase of the resistance of the primary, middle and high-efficiency filters, to maintain the cleanliness of the room, the air volume of the fresh air, air supply and return air needs to be kept consistent, therefore, a variable frequency fan is set up in the air conditioning system to achieve the requirements of purification and air supply by changing the fan frequency and fixing the air volume and air pressure, and at the same time, energy saving can be achieved. 2) The air conditioning system should be pressure tested, cleaned, and descaled before operation each year to prevent a reduction in heat transfer efficiency and increase operating costs. 3) Regularly replace the primary and secondary filters of the air conditioning system to reduce the waste of wind energy. 4) Increase the use of fresh outdoor air in the transitional season to regulate indoor temperature and humidity. 5) Under the premise of meeting the temperature and humidity requirements of the clean area, appropriately increase (summer) or decrease (winter) the temperature and humidity control value.