Selecting high-efficiency air filters (especially HEPA filters) is a highly technical task, and understanding their technical parameters is crucial. Below is a checklist of core technical parameters and their explanations to help you make an informed decision.
Core Performance Parameters (Determining Filtration Effectiveness)
1. Filtration Efficiency: The percentage of particles captured by the filter, which is the most critical parameter. Pay attention to its efficiency against MPPS (Most Penetrating Particle Size). MPPS is the particle size that is most difficult for the filter to capture, typically between 0.1 and 0.3 micrometers. Efficiency marked against MPPS most accurately reflects the performance of a HEPA filter.
2. Efficiency Classification Standard: Refer to internationally recognized standards such as EN 1822 (European) or GB/T 6165 (Chinese National Standard). Common classifications include:
- H13: Filtration efficiency against MPPS ≥ 99.95%
- H14: Filtration efficiency against MPPS ≥ 99.995%
- Note: Beware of products that only claim "99.97% efficiency against 0.3-micron particles." Always request a test report based on MPPS from EN 1822 or GB/T 6165 standards from the supplier.
3. Initial Resistance: The airflow resistance of a new filter operating at its rated airflow, measured in Pascals (Pa). Resistance directly affects energy consumption and operating costs. Lower initial resistance means less energy consumption by the fan, resulting in greater energy savings. When choosing between two filters with the same efficiency, opt for the one with lower initial resistance.
4. Dust Holding Capacity: The total weight of specific test dust that the filter can hold before reaching its specified final resistance value, measured in grams (g). Dust holding capacity directly determines the service life of the filter. The higher the dust holding capacity, the more dust the filter can adsorb, the longer its service life, and the lower its replacement frequency.
Physical Specification Parameters (Determining Usability)
1. Dimensions: The length, width, and height (or depth) of the filter, typically measured in millimeters (mm). These dimensions must match the installation space in your equipment exactly. Even a few millimeters of difference can prevent proper installation.
2. Rated Airflow: The optimal airflow range for which the filter is designed, measured in cubic meters per hour (m³/h). The selected airflow must fall within the filter's rated airflow range. Exceeding this range can lead to a sharp increase in resistance, reduced efficiency, and increased noise levels. Operating below the rated airflow may fail to effectively cover the entire filtration area.
Comprehensive Quality and Reliability Parameters
1. Filter Media: The material used to manufacture the filter core, typically ultrafine glass fiber paper or PP (polypropylene) PET materials. Glass fiber paper is the mainstream material for traditional high-efficiency filters, known for its stable performance. PP/PET materials are more moisture-resistant, but for high-performance levels (such as H13/H14), glass fiber remains the primary choice.
2. Sealing: The sealing process between the filter frame and the filter media to prevent unfiltered air from leaking. Even if the filter core has 100% efficiency, poor sealing can allow dirty air to bypass through gaps, significantly reducing the actual effectiveness. Check for reliable sealing methods such as gel seals (e.g., polyurethane adhesive).
3. Frame Material: The material of the filter's outer frame, commonly available in paper, aluminum profiles, stainless steel, and plastic. This affects durability and environmental adaptability. Paper frames are cost-effective but not moisture-resistant; aluminum frames are strong, resistant to deformation, and durable, making them a popular choice; stainless steel frames are used in highly corrosive environments.
