How to choose the right high-efficiency filter for the air shower?

When choosing a high-efficiency filter suitable for a material shower room, factors such as cleanliness level, air flow parameters, installation space, and usage scenarios need to be comprehensively considered. The following is a detailed selection guide and key points:
1. Clearly define the cleanliness grade requirements for the material shower room
Clean area grade matching
Air showers are typically used at the entrances of clean areas in industries such as pharmaceuticals, electronics, and food. The efficiency of the filters should be selected based on the grade of the downstream clean area.
ISO Grade 5 (Class 100) and above: HEPA (High Efficiency Air Filter) must be selected, with an efficiency grade of ≥H13 (filtration efficiency ≥99.97% @ 0.3μm particles).
ISO 6-7 grade (Class 1000-10000): H11-H12 grade HEPA (filtration efficiency 98%-99.9%) can be selected.
For low-grade clean areas or general purification scenarios, Sub-high efficiency filters (E10-E12) can be considered, but it is necessary to ensure that the air velocity of the air shower meets the standards.
Industry standard reference
Pharmaceutical industry: Compliance with GMP standards is required. Filters of H13 grade or above are recommended and must pass integrity tests (such as PAO tests).
In the electronics industry, for semiconductor workshops and other areas where nanoscale particles need to be controlled, it is recommended to choose H14 grade or ULPA (ultra-high efficiency filter, efficiency ≥ 99.9995%@0.12 μm).
Second, determine the structure and type of the filter
Select by structural form
Type characteristics, applicable scenarios
The non-partitioned type uses hot melt adhesive to separate the filter paper, with a thin thickness (25-70mm), small volume, moderate dust holding capacity, and relatively low cost. Limited space material shower room, conventional clean area.
The partitioned type uses aluminum foil or paper partitions to separate the filter paper, with a large thickness (220-300mm), high dust holding capacity, and slightly greater resistance. Scenarios with high air volume or those requiring long-term operation.
The liquid trough frame is immersed in the sealing liquid trough, featuring excellent sealing performance and no risk of leakage. It is suitable for high-grade clean areas. Clean areas of ISO grade 5 and above must be strictly sealed.
The combined multiple filters are integrated into the frame, which is convenient for the installation of large-sized air outlets and ensures good uniformity of air volume. High-volume air shower (such as double-door counter-blowing type).
Select by installation method.
Compression type: The sealing gasket is tightly pressed by frame bolts, which makes it easy to install and suitable for conventional material shower rooms.
Liquid tank type: It requires a liquid tank frame and is filled with sealant liquid. It is suitable for strict sealing requirements (such as biosafety laboratories).
Iii. Key parameters: Match the performance of the air shower
Air volume and filtration area
The air volume of the fan in the material shower room should match the rated air volume of the filter (for example, if the rated air volume of the filter is 1000m³/h, the air volume of the fan in the material shower room should be ≥800m³/h, with a 20% margin).
The larger the filtration area, the higher the dust holding capacity and the longer the service life: it can be calculated according to the formula filtration area = air volume ÷ face velocity (face velocity is usually taken as 0.3-0.45m/s).
Resistance and Energy Consumption
The lower the initial resistance, the lower the energy consumption of the fan: the initial resistance of the filter without separators is approximately 200-250Pa, that of the filter with separators is about 250-300Pa, and that of the liquid tank type is about 280-320Pa.
It is necessary to balance efficiency and resistance to avoid a decrease in the air shower velocity due to excessive resistance (standard air shower velocity ≥20m/s).
Dimensions and installation space
Measure the dimensions (length × width × thickness) of the installation frame of the material shower room filter. Common specifications include:
610×610×220mm (with partition), 610×610×69mm (without partition), 1220×610×69mm (without partition), etc.
Pay attention to the fit clearance between the filter and the frame (≤2mm) to avoid seal failure.
Iv. Material and Durability Requirements
Filter paper material
Glass fiber filter paper: The mainstream material for conventional HEPA/ULPA filters, resistant to high temperatures (≤250℃), but it should be kept away from moisture (which may cause a decrease in strength).
Polypropylene (PP) filter paper: It has good moisture resistance and is suitable for high-humidity environments (such as food workshops), but its temperature resistance is relatively low (≤80℃).
Frame material
Material characteristics and applicable scenarios
Aluminum alloy is lightweight, corrosion-resistant, and low-cost, making it suitable for most clean areas. Conventional material shower room, non-high-temperature environment.
Galvanized steel sheets have high strength and low cost, but they have poor corrosion resistance and should be kept away from damp environments. Drying workshops or temporary usage scenarios.
Stainless steel is corrosion-resistant, easy to clean, and suitable for damp or corrosive environments (such as the pharmaceutical and food industries). Scenarios with high cleanliness and requiring disinfection resistance.
Wood has a low cost, but it is prone to moisture and deformation, and is only suitable for low-grade clean areas. Non-critical areas, short-term use.
Resistance to disinfection
The air shower room often uses disinfectants such as alcohol and hydrogen peroxide, and the filter needs to be able to withstand frequent disinfection.
The frame and sealant should be made of chemically resistant materials (such as silicone sealant, ethylene propylene diene monomer rubber gasket).
If formaldehyde fumigation is used, it is necessary to confirm that the filter material is formaldehyde-resistant (glass fiber filter paper should avoid long-term contact with formaldehyde).
Balance the house, cost, and maintenance cycle
Initial cost and lifespan
The cost of the filter without separators is lower than that of the filter with separators, but it has a lower dust holding capacity and a shorter replacement cycle. The liquid tank type has the highest cost, but it has reliable sealing and is suitable for long-term use.
Calculate the total cost of ownership (TCO): initial procurement cost + replacement and maintenance cost + energy consumption cost, and give priority to the solution with high cost performance.
Maintenance convenience
Choose filters of common market specifications (such as 610×610mm) for quick procurement and replacement. Special specifications need to be customized with the manufacturer in advance.
Vi. Selection Suggestions for Special Scenarios
Explosion-proof environment
For the material shower rooms in chemical and hazardous materials workshops, explosion-proof filters should be selected. The frame material should be stainless steel, and the filters should have no risk of static electricity accumulation (the filter paper needs to be treated for anti-static purposes).
High-temperature environment
If the air shower needs to withstand high temperatures (such as the entrance of an oven), high-temperature resistant filters (glass fiber filter paper + stainless steel frame, with a temperature resistance of ≥250℃) should be selected.
Biosafety scenarios
In scenarios such as biological laboratories and vaccine workshops that require inactivation treatment, the filters need to support in-situ disinfection (such as steam sterilization), and when replacing, it is necessary to prevent microbial leakage (it is recommended to use a liquid tank type + bag out structure).
Selection summary steps
Confirm the clean area grade and efficiency requirements (H13/H14/ULPA);
Measure the installation space dimensions and select the structural type (without partition/with partition/liquid tank type);
Match the parameters of air volume, resistance, and face velocity;
Determine the material (moisture-resistant, disinfection-resistant, high-temperature resistant, etc.);
Review brand certification and test reports.
Balance costs and maintenance cycles and select the optimal solution.
Through comprehensive selection based on the above dimensions, it can be ensured that the performance of the high-efficiency filter matches that of the material shower room, which not only meets the standards of the clean area but also reduces the later maintenance costs.