What Is a HEPA Filter
HEPA (High-Efficiency Particulate Air) filters are mainly used to capture fine particles smaller than 0.3 microns, including dust and various suspended matter. They are made using ultra-fine fiberglass paper as the filter media, combined with separator materials such as kraft paper or aluminum foil, and assembled with wooden or aluminum alloy frames.
These filters are known for their high efficiency, low resistance, and large dust-holding capacity. HEPA filters are widely used in terminal air supply systems for cleanrooms in industries like optical electronics, LCD manufacturing, biopharmaceuticals, precision instruments, food and beverage processing, and PCB printing. Both HEPA and ultra-HEPA filters are essential for the final filtration stage in clean environments.
Types of HEPA Filters
HEPA filters come in various structural types, including:
- Separator HEPA filters
- Separatorless HEPA filters
- High-airflow HEPA filters
- Gel-sealed HEPA filters
- High-temperature-resistant HEPA filters
Additionally, there are three other specialized types:
- Ultra-HEPA filters, capable of removing up to 99.9995% of airborne particles.
- Antibacterial separatorless HEPA filters, which incorporate antimicrobial properties to prevent bacteria from entering cleanrooms.
- Sub-HEPA filters, which are more affordable and typically used in areas with lower cleanliness requirements.
Separator HEPA Filters
These filters use ultra-fine fiberglass or polypropylene paper, folded into dense pleats. Spacers made of kraft paper or aluminum foil are placed between the folds to maintain proper airflow. The outer frame is typically made of galvanized steel or aluminum alloy, sealed with modern polyurethane adhesive for a secure and airtight finish.
Separatorless HEPA Filters
Also made from ultra-fine fiberglass or polypropylene filter paper, these filters use hot-melt glue to maintain the pleat spacing, eliminating the need for physical separators. The frame may be aluminum alloy, wood, or galvanized steel, and is sealed with environmentally friendly polyurethane gel.
High-Airflow HEPA Filters
Also known as W-type or V-type filters, these are widely used in central HVAC and large-scale ventilation systems. They are often interchangeable with bag filters but take up less space. While more compact, they tend to be slightly more expensive than conventional bag-type filters.
Gel-Sealed HEPA Filters
Gel sealing is one of the most reliable mechanical sealing methods used today. These filters are easy to install, provide excellent sealing performance, and are commonly used in high-efficiency air filtration systems in cleanrooms and other critical environments.
High-Temperature Resistant HEPA Filters
These filters are designed with separators that help maintain uniform pleat spacing and ensure maximum use of the filter media with minimal resistance. Both sides of the filter media are folded into 180-degree pleats, with wedge-shaped pocket folds formed by double creasing, which helps prevent media damage.
Key specifications:
- Filter media: High-temperature fiberglass paper
- Frame: Stainless steel or aluminum alloy
- Sealant: High-temperature silicone
- Gasket: Silicone rubber
- Efficiency: 99.99% at 0.3 microns (H13 grade, tested individually using laser particle counters)
- Continuous temperature tolerance: 300°C
Maintenance Tips for HEPA Filters
To maintain performance and extend service life, HEPA filters should be serviced regularly—ideally every 6 to 12 months. During maintenance:
- Carefully remove the filter
- Use a vacuum cleaner to remove surface dust
- Wipe the surface with alcohol or a neutral cleaner
- Reinstall the filter securely
It is important to avoid damaging the filter’s frame or internal structure during cleaning, as this could compromise filtration efficiency.
Conclusion
Choosing the right HEPA filter is critical for maintaining cleanroom standards and ensuring the reliability of air handling systems. With a range of options tailored to different environments—from ultra-clean pharmaceutical labs to high-temperature industrial settings—HEPA filters remain the gold standard in fine particulate filtration.
At E-FILT, we specialize in designing and manufacturing high-performance HEPA and ULPA filters that meet international standards for efficiency, durability, and safety. Whether you need standard models or customized filtration solutions, our products are trusted by clients worldwide across electronics, biotech, food processing, and more. Contact E-FILT today to discover how we can support your air purification needs with confidence.
