As the core component of the “primary – medium – high efficiency/ultra-high efficiency” three-stage filtration system in the air purification system, the medium-efficiency bag filter mainly functions to intercept 0.5 to 10μm particles (such as dust, pollen, fine fibers, and some microorganisms) that are not captured by the primary filter, reducing the load on the high-efficiency filter at the back end and extending its service life. At the same time, further enhance the air cleanliness. With the characteristics of “high dust holding capacity, low resistance and strong adaptability of filtration efficiency”, it is widely used in scenarios where there are clear requirements for air quality but no need to reach extremely high cleanliness standards (such as Class 100, Class 10). Specifically, it can be divided into the following six major categories:
I. Medical and health field: Ensure a sterile and low-bacterial environment
Medical scenarios are sensitive to microbial and particulate contamination. Medium-efficiency bag filters are the “key barrier” of clean air conditioning systems, with the core function of controlling the risk of nosocomial infections. Specific applications include:
Hospital clean areas: such as Class III to IV clean operating rooms (corresponding to Class 10,000 and Class 100,000 cleanliness levels), icus (Intensive Care Units), neonatal intensive care units (NICUs), intravenous drug preparation centers (PIVAS, B-level areas), general preparation rooms, medical laboratories (such as microbiological testing rooms), etc. Usually, F7 to F8 grade (EN 779 standard) filters are selected. In some high-risk areas (such as PIVAS), antibacterial filter materials are used to prevent the growth of mold and bacteria on the filters themselves.
Pharmaceutical production workshops: Clean areas for non-sterile drug production (such as oral solid dosage form workshops, traditional Chinese medicine extraction workshops), drug storage areas (raw material warehouses where dust and humidity need to be controlled), and medical device assembly workshops (such as assembly of general medical consumables). Such scenarios must comply with the “Good Manufacturing Practice for Pharmaceutical Products” (GMP). The filter efficiency is mostly F6 to F7 grade, focusing on intercepting the powder and equipment wear particles generated during the production process.
Moving to another crucial sector, the electronics and precision manufacturing field focuses on: Protecting precision equipment and products.
The electronics and precision manufacturing industries are extremely sensitive to “micro-particle contamination” (tiny particles may cause chip short circuits and the scrapping of precision parts). Medium-efficiency bag filters are used for front-end pretreatment to reduce the load on high-efficiency filters at the back end. Specific applications include
Pharmaceutical production workshops: Clean areas for non-sterile drug production (such as oral solid dosage form workshops, traditional Chinese medicine extraction workshops), drug storage areas (raw material warehouses where dust and humidity need to be controlled), and medical device assembly workshops (such as assembly of general medical consumables). Such scenarios must comply with the “Good Manufacturing Practice for Pharmaceutical Products” (GMP). The filter efficiency is mostly F6 to F7 grade, focusing on intercepting the powder and equipment wear particles generated during the production process.
Moving to another crucial sector, the electronics and precision manufacturing field focuses on: Protecting precision equipment and products.
The electronics and precision manufacturing industries are extremely sensitive to “micro-particle contamination” (tiny particles may cause chip short circuits and the scrapping of precision parts). Medium-efficiency bag filters are used for front-end pretreatment to reduce the load on high-efficiency filters at the back end. Specific applications include
Electronic component production: such as semiconductor packaging and testing workshops (non-core lithography areas), PCB (printed circuit board) production workshops, and electronic component (resistor, capacitor) assembly workshops. Usually, F7 to F8 grade filters are selected to intercept solder dust, resin particles and metal shavings in the workshop.
Precision instrument manufacturing: such as optical instrument (lens, telescope) assembly workshops, sensor production workshops, and small precision machinery (such as watch parts) processing areas. It is necessary to control the fine dust in the air (≤5μm) to prevent particles from adhering to the surface of precision components and affecting accuracy. The filter efficiency is mainly F8 grade.
Next, the food and beverage processing field emphasizes: Control of microbial and dust contamination.
The food industry must comply with the “National Food Safety Standards”. The core function of medium-efficiency bag filters is to “intercept dust + reduce microbial carriers”, preventing raw materials and finished products from being contaminated. Specific applications include:
Precision instrument manufacturing: such as optical instrument (lens, telescope) assembly workshops, sensor production workshops, and small precision machinery (such as watch parts) processing areas. It is necessary to control the fine dust in the air (≤5μm) to prevent particles from adhering to the surface of precision components and affecting accuracy. The filter efficiency is mainly F8 grade.
Next, the food and beverage processing field emphasizes: Control of microbial and dust contamination.
The food industry must comply with the “National Food Safety Standards”. The core function of medium-efficiency bag filters is to “intercept dust + reduce microbial carriers”, preventing raw materials and finished products from being contaminated. Specific applications include:
Food processing workshops: such as baking workshops (intercepting flour dust to prevent dust explosion risks + microbial contamination), dairy product processing (clean areas before liquid milk filling to control bacterial spores in the air), meat product processing (cooling rooms, packaging rooms to reduce Salmonella and Escherichia coli carried by dust). F6 to F7 grade filters are mostly selected. In some high-temperature and high-humidity scenarios (such as dairy workshops), anti-mold filter materials are often used in combination.
Beverage production workshops: such as filling workshops for bottled water and fruit juice (non-aseptic filling lines), and mixing workshops for beverage raw materials (such as powdered sugar and flavoring), with a focus on intercepting raw material dust and suspended microorganisms in the air to prevent product deterioration.
Iv. Commercial and Public Building Sector: Enhance indoor air comfort
Air conditioning systems in commercial and public buildings need to balance “air cleanliness” and “energy consumption cost”. Medium-efficiency bag filters are used to improve indoor air quality and reduce the impact of dust and pollen on people. Specific applications include:
Beverage production workshops: such as filling workshops for bottled water and fruit juice (non-aseptic filling lines), and mixing workshops for beverage raw materials (such as powdered sugar and flavoring), with a focus on intercepting raw material dust and suspended microorganisms in the air to prevent product deterioration.
Iv. Commercial and Public Building Sector: Enhance indoor air comfort
Air conditioning systems in commercial and public buildings need to balance “air cleanliness” and “energy consumption cost”. Medium-efficiency bag filters are used to improve indoor air quality and reduce the impact of dust and pollen on people. Specific applications include:
Central air conditioning systems in large commercial Spaces such as shopping malls, supermarkets, and shopping centers (especially in areas with high ceilings and dense foot traffic) can intercept dust and vehicle exhaust particles brought in from outside, preventing dust accumulation at air conditioning vents and the generation of unpleasant odors. Usually, F5 to F6 grade filters are selected to balance the filtration effect and replacement cost.
Office and public venues: such as fresh air systems in Grade A office buildings, air conditioning filtration in hotel rooms, libraries (to protect books from dust erosion), gymnasiums (to reduce dust inhalation during exercise). Some places with high air quality requirements (such as high-end hotels and office buildings) will choose F6 grade filters to reduce the concentration of PM10.
Central air conditioning systems in transportation hubs such as airport terminals and high-speed railway stations intercept outdoor sand and exhaust particles, while reducing the spread of dust caused by personnel movement and enhancing the breathing comfort of passengers.
In general industry and manufacturing fields, the focus shifts to: Controlling production dust and protecting equipment.
Apart from precision manufacturing, medium-efficiency bag filters in general industrial scenarios are mainly used for “protecting production equipment” and “improving the working environment in workshops”. Specific applications include:
Mechanical processing workshops: such as machine tool processing and hardware manufacturing workshops, to intercept metal cutting dust and lubricating oil mist particles, prevent dust from entering the equipment interior and causing wear (such as bearings and motors), and at the same time reduce the occupational health risks of workers inhaling dust, F5 to F6 grade filters are mostly selected.
In the chemical and coating industries, such as coating blending and resin production workshops, to intercept chemical dust and particles accompanied by volatile organic compounds (VOCs), prevent dust from affecting product purity (such as uneven coating color), and at the same time reduce corrosion to workshop ventilation equipment, polyester fiber filter materials with chemical resistance (F6 grade) are usually selected.
Textile and furniture industry: such as the spinning workshop of textile factories (to intercept cotton fluff and fiber dust), and the spray painting workshop of furniture factories (to intercept paint mist particles), to prevent dust from adhering to the product surface and affecting quality (such as fabric pilling, paint surface defects of furniture).
Vi. Laboratory and Research Fields: Assist in controlling the experimental environment
Scientific research laboratories have specific requirements for air cleanliness (non-sterile laboratories). Medium-efficiency bag filters are used as front-end filters to support high-precision filtration at the back end. Specific applications include
For general scientific research laboratories, such as biological laboratories (non-microbiological culture areas), material laboratories (such as polymer material synthesis), and environmental monitoring laboratories, to intercept dust and pollen in the air and prevent particles from interfering with experimental results (such as material characterization experiments and sample analysis), F6 to F7 grade filters are usually selected.
Universities and research institutions: For instance, the fresh air systems in chemistry and physics laboratories of universities can reduce the entry of outdoor pollutants into the experimental area, protect experimental equipment (such as microscopes and spectrometers) from dust pollution, and ensure the accuracy of experimental data.
Summary: Reference for selecting efficiency levels in different scenarios
The core adaptation logic of medium-efficiency bag filters is “scene cleanliness requirements → efficiency grade matching”. The following table can visually reflect the selection differences in different scenarios:
Office and public venues: such as fresh air systems in Grade A office buildings, air conditioning filtration in hotel rooms, libraries (to protect books from dust erosion), gymnasiums (to reduce dust inhalation during exercise). Some places with high air quality requirements (such as high-end hotels and office buildings) will choose F6 grade filters to reduce the concentration of PM10.
Central air conditioning systems in transportation hubs such as airport terminals and high-speed railway stations intercept outdoor sand and exhaust particles, while reducing the spread of dust caused by personnel movement and enhancing the breathing comfort of passengers.
In general industry and manufacturing fields, the focus shifts to: Controlling production dust and protecting equipment.
Apart from precision manufacturing, medium-efficiency bag filters in general industrial scenarios are mainly used for “protecting production equipment” and “improving the working environment in workshops”. Specific applications include:
Mechanical processing workshops: such as machine tool processing and hardware manufacturing workshops, to intercept metal cutting dust and lubricating oil mist particles, prevent dust from entering the equipment interior and causing wear (such as bearings and motors), and at the same time reduce the occupational health risks of workers inhaling dust, F5 to F6 grade filters are mostly selected.
In the chemical and coating industries, such as coating blending and resin production workshops, to intercept chemical dust and particles accompanied by volatile organic compounds (VOCs), prevent dust from affecting product purity (such as uneven coating color), and at the same time reduce corrosion to workshop ventilation equipment, polyester fiber filter materials with chemical resistance (F6 grade) are usually selected.
Textile and furniture industry: such as the spinning workshop of textile factories (to intercept cotton fluff and fiber dust), and the spray painting workshop of furniture factories (to intercept paint mist particles), to prevent dust from adhering to the product surface and affecting quality (such as fabric pilling, paint surface defects of furniture).
Vi. Laboratory and Research Fields: Assist in controlling the experimental environment
Scientific research laboratories have specific requirements for air cleanliness (non-sterile laboratories). Medium-efficiency bag filters are used as front-end filters to support high-precision filtration at the back end. Specific applications include
For general scientific research laboratories, such as biological laboratories (non-microbiological culture areas), material laboratories (such as polymer material synthesis), and environmental monitoring laboratories, to intercept dust and pollen in the air and prevent particles from interfering with experimental results (such as material characterization experiments and sample analysis), F6 to F7 grade filters are usually selected.
Universities and research institutions: For instance, the fresh air systems in chemistry and physics laboratories of universities can reduce the entry of outdoor pollutants into the experimental area, protect experimental equipment (such as microscopes and spectrometers) from dust pollution, and ensure the accuracy of experimental data.
Summary: Reference for selecting efficiency levels in different scenarios
The core adaptation logic of medium-efficiency bag filters is “scene cleanliness requirements → efficiency grade matching”. The following table can visually reflect the selection differences in different scenarios:
| Application field | Typical scenarios | Recommended Efficiency grade (EN 779) | Core filtering objective |
| Medical and health care | Hospital ICU, PIVAS | F7 to F8 grades | Microorganisms, fine particles |
| Electronic precision manufacturing | Semiconductor packaging, optical instruments | F7 to F8 grades | Micro particles (≤5μm) |
| Food processing | Baking, dairy filling | Grade F6 to F7 | Dust, microorganisms |
| Commercial public buildings | Shopping malls, office buildings | Grade F5 to F6 | Dust, PM10 |
| Industrial general | Mechanical processing, chemical workshop | Grade F5 to F6 | Production dust and equipment protection |
| Laboratory | Ordinary scientific research laboratory | Grade F6 to F7 | Dust, experimental interference particles |
In summary, the application scenarios of medium-efficiency bag filters cover all fields including production, medical care, daily life and scientific research. Its core value lies in “connecting the upper and lower levels” – it not only links the coarse filtration of the primary filter but also reduces the burden on the high-efficiency filter at the back end. It is a key filtration link that balances air cleanliness, operating costs and equipment lifespan.
