Distinguishing the quality of HEPA/ULPA high-efficiency air filters in biosafety cabinets is the key to ensuring the core protective performance of the cabinets. This requires systematic technical discrimination from multiple dimensions such as product specifications, performance certification, structural processes, brand and compliance. The following are specific technical criteria that can serve as a basis for procurement, acceptance, and auditing.
Core discrimination principle
High quality filters must simultaneously meet the four requirements of "high efficiency, high integrity, high reliability, and long lifespan", and be supported by objective and verifiable technical evidence.
Filtering performance and compliance discrimination (hard indicators)
This is the primary and uncompromising dimension for judging quality.
1. Filtration efficiency standards and test reports
Key points for discrimination: Suppliers are required to provide a "filtration efficiency and resistance test report" issued by an independent third-party authoritative laboratory for specific filter models.
Key data:
Efficiency value: The filtration efficiency for particles with a diameter of 0.3 μ m (or 0.1-0.2 μ m for ULPA) must be clearly labeled. For biosafety cabinets, the efficiency of both air supply and exhaust filters should be ≥ 99.99% (i.e. H14 level or higher according to EN 1822 standard). The report should specify the testing methods (such as ISO 29463, IEST-RP-CC034).
Initial resistance: The initial resistance value at rated air volume. At the same efficiency, the lower the initial resistance, the more advanced the filter material technology, which can reduce the energy consumption and noise of the fan.
Dust holding capacity: The amount of dust that a filter can hold when the resistance reaches the specified value (usually twice the initial resistance). The higher the dust holding capacity, the longer the service life.
2. Integrity (scanning leak detection) and border sealing
Key points for discrimination: This is the gold standard for judging the manufacturing process of filters, especially the sealing process.
Key evidence:
100% factory leak detection report: High quality manufacturers will scan and leak detect each factory filter one by one, and provide a "qualified leak detection report for each filter" along with the goods, rather than a sampling report.
Scanning diagram and data: The report should include a scanning path diagram and clearly indicate the maximum leakage point value and average penetration rate. The qualified standard is that the local leakage rate at any point shall not exceed 0.01%.
Sealing technology: Inquire and verify the frame sealing process. The high-quality filter adopts robot automatic gluing to ensure that the glue line is uniform, continuous, and without breakpoints. The consistency of manually glued filters is poor, and there is a high risk of leakage.
Structural and material process discrimination (intrinsic quality)
This determines the mechanical strength, environmental adaptability, and long-term reliability of the filter.
1. Filter material
Material: The mainstream is ultra-fine glass fiber paper. Should be asked if it has undergone waterproof (hydrophobic) treatment. Processed filter media can prevent moisture from entering and causing a decrease in filter strength or microbial growth, which is particularly important in humid and hot environments or during disinfection.
Partition board:
Material: Preferred corrosion-resistant aviation aluminum foil or environmentally friendly hot melt adhesive,
Frame and sealing
Frame material: extruded aluminum alloy profiles are the best choice, with light weight, high strength, no deformation, and easy sealing. Wooden frames have been largely phased out due to their susceptibility to moisture and deformation, leading to leakage.
sealant:
Type: It should be polyurethane (PU) or silicone elastic sealant, which maintains soft elasticity after curing and can compensate for vibration and thermal expansion and contraction during equipment operation.
Compatibility: It must be declared that it can withstand long-term exposure to commonly used laboratory disinfectants (such as 70% isopropanol, hydrogen peroxide vapor) without swelling, cracking, or delamination.
structural design
2. Anti leakage design: The overlap between the filter material and the frame should have anti leakage pressure strips or sealing gaskets, which is the key to avoiding "bypass leakage".
3. Installation auxiliary design: There should be clear airflow direction arrows and model labels on the frame. Good design facilitates installation and positioning in narrow spaces.
Matching and System Integration Discrimination
The filter must be perfectly matched with the target safety cabinet.
1. Technical parameter matching
Size and air volume: The physical dimensions must be perfectly matched. The rated air volume should be equal to or slightly greater than the actual working air volume of the safety cabinet fan under the design resistance of the filter.
Resistance curve: Ideally, the resistance curve of the filter at different air volumes should be obtained and compared with the performance curve of the safety cabinet fan to ensure that the operating point is in the high-efficiency zone.
2. Manufacturer qualifications and compliance documents
Association of complete machine registration certificate: The most direct judgment is whether the filter model is listed in the attachment (product technical requirements) of the "Medical Device Registration Certificate" of the target biosafety cabinet, or whether it is designated as a replacement component by the original factory.
3. Original factory vs third-party: Original factory filters provide the most assurance in terms of compatibility and responsibility traceability. A reputable third-party filter manufacturer should be able to provide compatibility statements and numerous successful application cases with mainstream safety cabinet brand models.
On site acceptance and long-term performance evaluation
The quality ultimately needs to be verified during use.
Leak detection after on-site installation
Necessary steps: After the installation of the new filter or during annual maintenance, a professional must use an aerosol photometer to perform on-site integrity scanning and leak detection.
Quality verification: A high-quality filter, after correct installation, should be able to easily and one-time pass on-site leak detection, with a smooth scanning curve and no abnormal peaks.
Service life and stability
Observing the rate of resistance increase: Under the same usage conditions, higher quality filters have a slower resistance increase and longer alarm intervals due to their higher dust holding capacity and optimized structure.
Long term sealing performance: after 1-2 years of use, it can still maintain excellent sealing performance in annual leak detection, indicating that its frame colloid and material have good anti-aging performance. Summary of Discrimination Process (Decision Checklist)
Request and review the following documents and information from suppliers or manufacturers:
【 Required 】 A third-party 'filtration efficiency and resistance test report' is required.
【 Required 】 Scan the leak detection qualification report for each unit before leaving the factory (along with the physical filter).
【 Required 】 Filter material description (filter material waterproof treatment, partition plate material, frame material, sealant type).
【 Required 】 Compatibility certificate (or original factory certificate) with the brand and model of the biosafety cabinet you are using.
[Inquiry] Do you provide installation guidance and support for on-site leak detection services after the first installation.
Compare the initial resistance and reference dust holding capacity at the same efficiency.
Verify whether the label information (model, efficiency, air volume, airflow direction) on the physical object is consistent with the report.
Final reminder: In the field of biosafety, paying a premium for filters is essentially paying for deterministic protective performance, longer replacement cycles, and lower lifecycle risks. Do not make decisions solely based on price, it should be seen as a critical safety investment rather than ordinary consumables. Choose brands and suppliers with long-term reputation and the ability to provide a complete technical evidence chain.