Detailed Explanation of G3/G4 Primary Efficiency Panel Pleated Air Filters
I. Core Functions and Efficiency Grading
G3/G4 filters serve as primary filtration units in air purification systems, primarily intercepting coarse particulates with diameters of 5-10μm (e.g., dust, pollen, fibers). Their efficiency grading is based on the EN 779 standard:
G3 Grade: Filtration efficiency ≥70% for particles ≥5μm (initial pressure drop ≈30Pa, final pressure drop 200Pa under ASHRAE standards).
G4 Grade: Filtration efficiency ≥90% for particles ≥5μm (initial pressure drop ≈38Pa, final pressure drop 250Pa under ASHRAE standards).
Typical Application Scenarios:
As prefilters for HVAC systems, cleanrooms, and industrial ventilation equipment, they extend the lifespan of downstream HEPA/ULPA filter elements and reduce maintenance costs. For example, in electronics factories, G4 filters can intercept over 80% of large particulates, prolonging the replacement cycle of HEPA filters by 40%.
II. Structural Design and Material Innovations
1. Pleated Structure Optimization
Through V-shaped or W-shaped pleat designs, the filtration area is increased by 30%-50% compared to traditional flat-panel filters, significantly reducing airflow resistance. For instance, a G4 pleated filter measuring 595×595×46mm can achieve an effective filtration area of 0.94㎡, while a flat-panel filter of the same size only offers 0.6㎡.
Metal Support Mesh: Covered with galvanized steel or aluminum mesh on the surface, it enhances mechanical strength, prevents filter media deformation, and extends service life to 8,000-12,000 hours (compared to 5,000-8,000 hours for traditional flat-panel filters).
2. Filter Media Upgrades
Polyester Fiber/Nylon Mesh: Wide temperature resistance range (-20℃ to 80℃), washable 2-3 times, suitable for environments with humidity ≤100%RH.
High-Temperature Fibrous Cotton: Some models (e.g., the KEL-AF series) support high-temperature conditions of 200-350℃, making them ideal for drying equipment and painting workshops.
3. Diverse Frame Options
Aluminum Alloy Frame: Lightweight (40% lighter than metal frames), highly corrosion-resistant, and compliant with cleanroom humidity control requirements.
Galvanized Steel/Plastic Frame: Lower cost, suitable for budget-sensitive projects.
III. Comparative Analysis of Performance Parameters
| Parameter | G3 Grade | G4 Grade | Traditional Flat-Panel Filter |
|---|---|---|---|
| Filtration Efficiency | ≥70% (≥5μm) | ≥90% (≥5μm) | ≥50% (≥5μm) |
| Initial Pressure Drop | 30Pa | 38Pa | ≥50Pa |
| Final Pressure Drop | 200Pa | 250Pa | 300Pa |
| Rated Airflow | 3000-3400m³/h (595×595×46mm) | 2800-3400m³/h (595×595×46mm) | 2000-2500m³/h (same size) |
| Replacement Cost | Reduced by 30% (extended lifespan) | Reduced by 30% (extended lifespan) | Higher |
Data Support:
Tests at a 12-inch wafer fab showed a 15% reduction in HVAC system energy consumption after adopting G4 pleated filters, saving over $200,000 annually in electricity costs.
G4 filters produced by Shenzhen Zhongjian Southern Environment have passed SEMI S2 certification, achieving a 98% interception rate for chemical contaminants in semiconductor wet processes.
IV. In-Depth Industry Application Analysis
1. Pharmaceutical Industry
Sterile Production Areas: G4 filters serve as prefilters for HEPA filter elements, intercepting microorganisms (e.g., bacteria, viruses) and particulates during drug production to ensure compliance with GMP standards. For example, after adopting a G4+H14 dual-stage filtration system, a biopharmaceutical company reduced the dynamic particle count (≥0.5μm) in its cleanroom from 3,520,000/m³ to ≤3,520/m³ (ISO Class 5).
Filling Line Air Protection: Prevent cross-contamination and ensure drug safety.
2. Semiconductor Industry
Wafer Manufacturing Environment: G4 filters remove silicon powder, metal particulates, and chemical vapors (e.g., HF, HCl) from the air, reducing wafer defect rates. A 12-inch wafer fab improved its yield by 2.3% and saved over $5 million annually after implementing a G4+U15 dual-stage filtration system.
Photolithography Process Protection: In conjunction with chemical filtration systems, they remove airborne organic contaminants (AMCs) to enhance photoresist imaging precision.
3. Commercial Buildings
Large Shopping Malls/Hospitals: G3 filters serve as primary filtration in HVAC systems, intercepting large particulates such as dust and pollen to extend the lifespan of medium-efficiency filters. For example, after adopting G3 filters, a Shanghai shopping mall reduced its HVAC system maintenance frequency by 50%.
V. Selection and Maintenance Guidelines
1. Selection Considerations
Efficiency Matching: Choose G3 (ISO Class 7-8) or G4 (ISO Class 5-6) based on cleanroom classification.
Airflow Calculation: Ensure the filter's rated airflow is ≥110% of the system's design airflow to avoid excessive pressure drops.
Certification Requirements: Prioritize products certified under EU GMP, FDA 21 CFR Part 11, etc.
2. Maintenance Strategies
Differential Pressure Monitoring: Replace filter elements when the final pressure drop reaches twice the initial pressure drop (typically ≤600Pa).
Integrity Testing: Conduct DOP/PAO scanning tests every six months to ensure no leaks.
Waste Disposal: Filter elements containing chemical contaminants must be disposed of in accordance with hazardous waste regulations.