What Technical Considerations Should Be Taken Into Account When Selecting Air Filter Products

The selection of air filters is indeed a systematic project that requires consideration of many dimensions. Simply put, the core of selection is to achieve the required air cleanliness of the system with the most economical energy consumption in a specific usage environment, while ensuring long-term stable operation.
To help you clarify your thoughts, I have categorized the technical issues that need to be considered when selecting into the following five levels:

• 1.1 Efficiency: Determine the filter grade (such as G4, F7, H13) based on cleanliness requirements, EN1822 (H13/H14), EN779 (G4/F9), ISO16890 (ISO ePM1)
• 1.2 Resistance: Pay attention to initial resistance and final resistance. The initial resistance should be ≤ 110% of the product sample value. The final resistance is usually set at 2-3 times the initial resistance, which directly affects the replacement cycle and energy consumption; Suggested final resistance: F5-F9 grade 300-400Pa; H11-H14 grade 400-600Pa
• 1.3 Air volume: Ensure that the rated air volume of the filter is equal to or greater than the system design air volume. It is recommended to control the actual operating air volume within 80% -120% of the rated air volume. 1.4 Dust Capacity: Reflects the ability of the filter to hold dust, directly affecting its service life. The supplier should provide this data.

Multi level filtering combination should not rely on single level filters, and should adopt a combination of coarse efficiency, medium efficiency, and high efficiency. If the front-end protection is done well, the lifespan of the high-efficiency filter at the end can be extended several times. For example, upgrading G4 pre filtration to F5 can extend the lifespan of the final F7 filter from 3 months to 6 months. The clean room can be equipped with G4+F8+H14, which can achieve a high-efficiency lifespan of up to 5 years at the end.

• 3.1 Temperature and Humidity: In high temperature (>80 ℃) and high humidity (>70% RH) environments, special filter materials and structures that are resistant to high temperatures and moisture should be selected.
• 3.2 Corrosivity: In corrosive environments such as coastal areas or chemical plants, the casing should be treated with 316L stainless steel or special coatings.
• 3.3 Explosion proof: Used in flammable and explosive environments such as coal mines and chemicals, it must comply with explosion-proof standards such as ATEX.
• 3.4 Installation location: Indoor/outdoor, waterproof, dustproof, and structural materials need to be considered.

Outer Frame, Filter Material, Sealing, Structural Form

• 4.1 Outer frame: Common types include aluminum alloy, galvanized steel, plastic, etc., which must meet the requirements of strength and corrosion resistance.
• 4.2 Filter materials: such as glass fiber (efficient), synthetic fiber (such as PTFE, low resistance, good chemical resistance), and polarizer (electrostatic reinforcement). 4.3 Sealing: The sealing of high-efficiency filters is crucial, and methods include contact packing sealing, liquid tank blade sealing, etc.
• 4.4 Structure: No partition (small volume, light weight, safer), with partition (high temperature resistance, high strength). For high cleanliness areas, it is recommended to use non partition high-efficiency filters to avoid the risk of particle emission that may be caused by partition materials.
• 4.5 Fire rating: shall comply with the relevant requirements of GB8624

Testing, Certification, Standards

• 5.1 Testing Report: The supplier is required to provide a type test report issued by CNAS or an internationally recognized laboratory, which complies with standards such as ISO 29461-1 (for turbomachinery), EN1822, GB/T6165, etc., to verify efficiency and resistance.
• 5.2 Unit by unit testing: For high-efficiency filters, leak detection must be carried out one by one to ensure that there are no leaks. Only after passing the inspection can they be shipped.
• 5.3 Compliance: Confirm compliance with international or local mandatory certification requirements such as CE and RoHS.
• 5.4 Relevant standards: ISO 29461-1, EN1822, GB/T13554

• 1. Clarify requirements: Firstly, determine your application scenarios (such as household fresh air, hospital operating rooms, gas turbine intake) and cleanliness targets (such as PM2.5 removal rate, ISO cleanliness level).
• 2. System design: Calculate the total air volume of the system, design a reasonable combination of front-end protection (pre filters), and ensure that the performance of each filter matches.
• 3. Product evaluation: Based on the above five levels, evaluate the technical parameters, environmental adaptability, structural materials, and compliance reports of candidate products one by one, and select the most suitable one, rather than the most expensive or cheapest one.