Exploring HEPA Filter Efficiency Levels from Primary to Advanced

With micron-sized particulate matter such as PM0.3 posing an increasing threat to indoor air quality, HEPA filters have emerged as an indispensable final barrier in clean environments. The selection of core filter media, along with its manufacturing process and long-term stability, plays a critical role in ensuring operational safety in high-purity industries such as healthcare, semiconductors, biopharmaceuticals, and new energy.

Here we provide a comprehensive review of air filtration materials, spanning from primary to high-efficiency grades. It emphasizes the processing challenges and optimization strategies associated with glass fiber HEPA filters, and offers industry-specific recommendations for filter media selection based on real-world case studies.

Three-Stage Air Filtration System

Primary-Efficiency Filter Media (G1–G4)

• Main materials: PET non-woven fabric (80–100 g/m²) + metal mesh support layer.
• Functional positioning: Intercepts large particles ≥ 5 μm (e.g., hair, dust) to protect downstream filter elements.
• Key parameters:
  • Filtration efficiency: 70% – 90%.
  • Air resistance: ≤ 30 Pa (air velocity 2 m/s).

Medium-Efficiency Filter Media (M5–F9)

• Material structure: PP/PET composite filter paper + electret-treated fiber layer.
• Technical features:
  • Graded filtration from 20 μm to 5 μm for deep filtration.
  • Electret charge enhances capture of 0.5–1 μm particles, increasing dust holding capacity by 40%.
  • Filtration performance: PM2.5 retention rate reaches 95% – 98% at F9 grade.

High-Efficiency Filter Media (HEPA Filter, H10–U17)

• Core material:
  • Ultrafine glass fiber filter paper (fiber diameter 0.3–0.5 μm).
  • Composite coatings (PP, PTFE) for enhanced strength and functionality.
• Performance:
  • Filtration efficiency ≥ 99.97% for 0.3 μm particles.
  • Features multiple advantages, including self-cleaning, moisture resistance, and oil repellency.

Glass Fiber HEPA Filter

• Traditional Challenge: Brittleness limits processing efficiency.
  • Conventional pleating equipment often damages the filter paper during forming, resulting in a breakage rate of up to 15%.
  • Fiber structure collapse is prone to occur during long-distance transportation, leading to a 30% decrease in filtration efficiency.
• Process Innovation: Roll-pleating and thermal setting technology.
  • Pleating system upgrade:
    • Ceramic rollers replace metal blades, reducing contact damage by 60%.
    • A spring-buffered V-shaped pleating device is better suited to the tension profile of glass fiber tension.
  • Heat setting reinforcement:
    • Sequential heating at 120 °C, 80 °C, and 40 °C solidifies the fiber structure.
    • Nano-silica coating fills the gaps between fibers, effectively suppressing pleat rebound.
• Data Comparison: Traditional Process vs Optimized Solution

  Table 1: Comparison of HEPA Filter Pleating Process Performance

  Process Method	Breakage Rate	Dust Holding Capacity (g/m2)	0.3 μm Filtration Efficiency
  Standard Blade Pleating	0.152	280	0.9991
  Roller Precision Pleating	0.008	420	0.9999

HEPA Filter Performance Breakthrough: Material Upgrade and Smart Manufacturing

• High-Performance Composite Material Design
  • Three-layer structure:
    • Middle layer: Ultra-fine glass fiber (50 μm).
    • Support layer: PET nanoscale support mesh (30 μm).
    • Surface layer: Antibacterial PP coating.
  • Performance highlights:
    • Bending resistance lifespan > 500,000 cycles (tested per ISO 16890).
    • Efficiency loss < 2% in high humidity conditions (95% RH).
    • Antimicrobial and anti-mildew properties are certified by ASTM F3502.
• Intelligent Pleating System: PLHP-700/1300
  • Real-time tension fluctuation monitoring with automatic roller gap adjustment (accuracy ±0.05 mm).
  • Supports multiple pleat configurations to enhance the effective filtration area and system airflow adaptability.
• Industry Application Cases
  • Automotive cabin air filters: Glass fiber-PTFE composite filter media, 99.99% filtration efficiency for PM0.3, and passed 150 °C thermal shock test.
  • Biopharmaceutical cleanrooms: U15-grade ultra-high efficiency filter media, combined with gel seal technology to meet ISO 14644 Class 5 cleanroom standard.

HEPA Filter Selection Guide

Customization Support & Sample Request

• Free Sample: Apply for a 3-stage filter media trial pack (including test report).
• Technical Consultation: Contact our engineers to customize pleating parameters.

From capturing visible dust to blocking nanoparticles, the technological evolution of HEPA filters is not just a manufacturing challenge – it is a continuous commitment to safeguarding human respiratory health. We are dedicated to developing more robust, more efficient, and smarter HEPA filter solutions, protecting clean spaces today while advancing toward a healthier tomorrow.