The Critical Role of HEPA Air Filters in Cleanrooms
1. Basic Principles of HEPA Air Filtration
HEPA air filters operate through a combination of physical interception, inertial impaction, diffusion, and electrostatic attraction to effectively trap airborne particles:
- Interception: When particles follow the airflow and pass close to the fiber surfaces of the filter media, they are directly captured due to contact.
- Inertial Impaction: Larger particles, due to their mass and inertia, cannot adjust their path with the airflow and collide with the fibers.
- Diffusion: Ultrafine particles, affected by Brownian motion, move irregularly and are more likely to come into contact with the filter fibers.
- Electrostatic Attraction: Some HEPA filters are made with electrostatically charged media, which enhances their ability to attract and retain tiny particles.
2. Functions and Benefits of HEPA Air Filters in Cleanrooms
(1) Final Stage Air Purification
HEPA air filters efficiently remove fine particles, bacteria, viruses, and other contaminants from the air, ensuring that cleanroom environments meet strict cleanliness standards. These filters are widely used in ISO Class 5 to Class 7 clean areas, providing a critical safeguard for sensitive processes and laboratory operations.
(2) Maintaining a Stable Clean Environment
With continuous and reliable performance, HEPA air filters help minimize the accumulation and circulation of airborne particles inside the cleanroom. By blocking external pollutants and expelling internal contaminants, they help maintain a dynamic balance of cleanliness essential for consistent operations.
(3) Protecting Downstream Equipment and Products
Installed at the final stage of the air handling system, HEPA filters serve as the last line of defense, delivering ultra-clean air into cleanrooms. This not only ensures environmental purity but also protects sensitive equipment and high-value products from airborne damage—ultimately enhancing product quality and manufacturing efficiency.
3. Key Technical Parameters and Selection Criteria
(1) Filtration Efficiency
Efficiency is one of the most critical performance metrics for a HEPA air filter. It is typically rated based on the filter’s ability to capture ≥0.3 μm particles, with premium filters achieving an efficiency of 99.97% or higher. Higher efficiency means greater particle capture capability and better air purification results.
(2) Resistance (Pressure Drop)
Resistance indicates the filter’s impact on airflow. Initial resistance refers to the pressure drop when the filter is new and operating at rated airflow—commonly ≤250 Pa. Final resistance marks the point at which the filter should be replaced, usually ≤450 Pa. Lower resistance helps reduce energy consumption and operating costs in the ventilation system.
(3) Filter Media
HEPA air filters are typically made with advanced materials such as fiberglass, PTFE membranes, or synthetic paper. These materials offer excellent filtration efficiency, chemical stability, and mechanical strength, making them suitable for demanding cleanroom environments.
(4) Sizes and Configurations
HEPA air filters come in a variety of standardized sizes, such as 610×610 mm and 484×484 mm, making them easy to install and replace. They are available in various structural designs—including separator, mini-pleat, pocket, and panel styles—to suit different cleanroom layouts and application needs.
About E-FILT
E-FILT is a trusted air filter manufacturer specializing in the design and production of high-performance HEPA air filters for cleanroom and critical environment applications. With a strong focus on quality, innovation, and reliability, E-FILT provides filtration solutions that meet global standards across industries such as pharmaceuticals, electronics, healthcare, and precision manufacturing. Whether you need standard or customized filter solutions, E-FILT is your professional partner in clean air technology.
