HEPA / ULPA Filters

HEPA / ULPA Filters

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HEPA filters (High Efficiency Particulate Air) and ULPA filters (Ultra Low Particulate Air) are the core filtration components for high-cleanliness environments. Under EN 1822, HEPA covers H13 (99.95%) and H14 (99.995%); ULPA covers U15, U16, and U17, reaching efficiencies up to 99.9999995%. The widely-mentioned H10, H11, and H12 grades are classified as EPA (Efficient Particulate Air) under EN 1822, with efficiencies from 85% to 99.5%, and are typically used as pre-filtration. HEPA filter testing is based on MPPS (Most Penetrating Particle Size, approximately 0.12–0.25μm), which most accurately reflects actual filter performance at the most difficult-to-capture particle size range.

Specification options include standard aluminum-frame gel-seal type, knife-edge seal type, stainless steel corrosion-resistant type, and dry-box type, with aluminum foil or hot-melt adhesive line separators, or separator-free construction. Each unit undergoes individual DOP/PAO aerosol scan testing at the factory, with test reports provided. Selection must consider rated airflow, initial pressure drop, frame material compatibility, sealing mechanism, and test methodology.

Typical applications: semiconductor front-end wafer fabrication and back-end packaging, TFT-LCD and OLED display production lines, BSL-2/3 biosafety laboratories, aseptic pharmaceutical filling zones, positive and negative pressure hospital operating rooms, and PCR testing facilities.

Frequently Asked Questions

HEPA filter grade comparison: H10, H11, H12, H13, H14, U15 — how to choose?
Under EN 1822: H13 (99.95%) is basic HEPA, H14 (99.995%) is standard HEPA, U15–U17 are ULPA (99.9995%+). The H10/H11/H12 grades commonly seen in the market are classified as EPA (Efficient Particulate Air, 85%–99.5%) under EN 1822 and serve as pre-filtration. Selection mapping per ISO 14644: Class 5 uses H14, Class 6–7 uses H13, Class 8 uses H12, Class 9 can use H11. Upgrade to ULPA only for semiconductor lithography or nanoscale processes.
Can HEPA filters be washed?
No. HEPA filters use the dense structure of glass fiber media combined with electret electrostatic effects to capture 0.3μm particles — washing destroys the fiber structure and charge, permanently degrading efficiency. Professional HEPA filters (H13/H14) are designed as single-use; replace the entire unit when end-of-life is reached. Washable filters on the market are mostly G3/G4 pre-filter grades with only 30%–95% efficiency, not true HEPA.
How long do HEPA filters last? When should they be replaced?
Lifespan depends on three triggers; replace when any is met: 1) pressure drop reaches 2× initial value (typically 1–3 years), 2) cleanliness testing fails, 3) accumulated runtime exceeds manufacturer recommendation (usually 18–36 months). For semiconductor processes, online differential pressure monitoring saves 30%–40% cost vs. time-based replacement. Baisheng provides on-site pressure measurement and replacement consultation.
What is the difference between HEPA and ULPA filters?
Under EN 1822: HEPA covers H13 (99.95%) and H14 (99.995%); ULPA covers U15 (99.9995%), U16 (99.99995%), and U17 (99.9999995%). ULPA is used in more demanding applications than HEPA, such as semiconductor front-end wafer fabrication, nanoscale processes, and BSL-4 laboratories.
What is MPPS and why is it used as the test benchmark?
MPPS (Most Penetrating Particle Size) is the hardest-to-capture particle size, approximately 0.12–0.25μm. EN 1822 uses MPPS as its test benchmark to most accurately reflect actual filter performance. Compared to the traditional 0.3μm DOP test, MPPS is more rigorous and better represents worst-case filtration efficiency.
What sealing methods are available for HEPA filters?
The three main types are: Gel Seal (best airtightness, used in semiconductor cleanrooms), Knife Edge (used in biosafety cabinets), and Gasket (lower cost, suitable for general cleanliness requirements). The right choice depends on the required leak tightness and installation environment.
Is each HEPA filter tested individually before shipment?
Yes. All Baisheng Tech HEPA/ULPA filters undergo individual DOP/PAO aerosol scan testing before shipment. A test report is included with each unit, covering test airflow, penetration rate, and initial pressure drop. A Certificate of Conformance can be provided upon request.

Need Custom Filters?

Special sizes, specific efficiencies, special materials — we can customize to your exact requirements. Contact us for a quote.