Selecting the correct air filtration media is one of the most critical decisions in maintaining industrial HVAC performance, protecting downstream equipment, and ensuring compliance with indoor air quality (IAQ) regulations.
When evaluating European EN 779 standards and their modern ISO 16890 equivalents, buyers frequently navigate two primary filter classifications: G1–G4 (Primary/Coarse Filters) and F5–F9 (Medium/Fine Filters).
Understanding the technical boundaries between these ratings ensures your facility balances optimal air purity with manageable pressure drop and replacement costs.
Quick Comparison: G1–G4 vs. F5–F9 Standards
While G1–G4 filters focus on catching coarse airborne debris, F5–F9 filters remove sub-micron pollutants and fine particulates.
| Performance Metric | G1–G4 (Coarse / Primary Filters) | F5–F9 (Medium / Fine Filters) |
| Filter Classification | Primary / Coarse Filtration | Fine / Medium Secondary Filtration |
| Primary Target Size | Particles larger than 10 μm (sand, lint, heavy dust) | Fine particles from 0.4 μm to 10 μm (smoke, pollen, bacteria) |
| EN 779 Efficiency Metric | Average Arrestance ($A_m$): 60% – 90%+ | Average Efficiency ($E_m$): 40% – 95%+ |
| ISO 16890 Equivalent | ISO Coarse (30% – 90%) | ISO ePM10, ePM2.5, ePM1 |
| Filter Media Types | Synthetic fiber, synthetic filter roll goods, fiberglass pre-filters | Meltblown non-woven synthetic, micro-glass bag/pocket media |
| System Position | First stage (Pre-filter air intake) | Second / Intermediate stage (AHU supply air) |
G1–G4 Primary Filters: First Line of Defense
Technical Overview
G-class filters (G1, G2, G3, G4) serve as the intake pre-filters in commercial and industrial air handling units (AHUs). Their function is purely mechanical: catching bulk dust and large airborne particulates before they penetrate deep into the ventilation system.
- G1–G2 (Light Intake): Used for basic coarse dust capture (Average Arrestance Am < 80%). Suitable for basic intake grilles, window units, and spray booth pre-filtration layers.
- G3–G4 (Commercial Pre-Filtration): High-capacity arrestance filters (Average Arrestance Am > 80% – 90%). Installed as direct pre-filters to keep cooling/heating coils, fans, and secondary fine filters clean.
Why Pre-Filtration Matters
Without a durable G3 or G4 pre-filter, expensive secondary fine filters (F7 or F9) become clogged prematurely. Operating without adequate pre-filtration dramatically increases static pressure, raises fan energy consumption, and shortens overall filter service life.
F5–F9 Medium & Fine Filters: High-Efficiency Purification
Technical Overview
F-class filters (F5, F6, F7, F8, F9) trap fine atmospheric dust, particulate matter (PM2.5 / PM1), smoke, and biological contaminants.
F5–F6 / ISO ePM10 (Medium Efficiency): Removes particles between 1.0–5.0 μm (Average Efficiency: 40%–80%). Popular in general office ventilation, commercial shopping malls, and food processing pre-stages.
F7–F8 / ISO ePM2.5 / ePM1 (Fine Efficiency): Traps fine respirable particles down to 0.4 μm (Average Efficiency: 80%–95%). Standard choice for commercial buildings, pharmaceutical production, and cleanroom supply air systems.
F9 / ISO ePM1 > 85% (Ultra-Fine Secondary): Delivers near-HEPA pre-stage performance. Acts as the final pre-filter directly protecting HEPA / ULPA banks in microelectronics, medical facilities, and critical paint curing lines.
Direct Source Manufacturing & OEM Solutions
Looking for custom-sized air filter media, pocket filter rolls, or complete OEM air filter assemblies for your distribution network or industrial project?
Why Partner With Chuqi:
Direct Factory Production: Integrated manufacturing from raw filter media roll goods to finished filter assemblies.
Global Standard Compliance: Fully tested and certified under EN 779 and ISO 16890 protocols.
Custom OEM/ODM Services: Custom dimensions, frame configurations (galvanized steel, aluminum, plastic), and private labeling options available.
Contact Our Technical Sales Team for Wholesale Quotes & Free Media Samples
