G1-4 Pre filter

Pre Filter (Primary Air Filter) is the first-stage coarse filtration component installed at the air intake of cleanroom ventilation systems including air handling units (AHU), FFUs, air showers, dynamic pass boxes and laminar flow ceiling air supply ducts. It intercepts large-size contaminants such as lint, hair, sand and coarse dust before airflow reaches high-efficiency HEPA filters, greatly reducing particle load on downstream HEPA media, extending HEPA service life by 2–3 times and lowering long-term maintenance cost of purification systems.

Classified by filtration efficiency as G3, G4 (EU standard) / MERV5–MERV8 (ASHRAE standard), it acts as the front protective barrier for all medium and high-efficiency cleanroom filters.

Main Structure & Material Composition

1. Outer Frame

Three common frame options for different working conditions:

1. Galvanized steel frame: Standard economical type, anti-rust, high structural rigidity, suitable for general cleanroom AHU and FFU;

2. Aluminum alloy frame: Lightweight, corrosion-resistant, easy disassembly, mainstream for air shower and FFU built-in pre-filters;

3. Stainless steel SUS304 frame: For high-humidity, frequent disinfection medical/pharma workshops, resistant to alcohol and chlorine sanitizers.

Frame thickness: 20mm / 25mm / 46mm standard sizes, matching universal filter rack dimensions.

2. Filtration Media

• Material: Progressive density synthetic polyester fiber, gradient layered structure (loose outer layer, dense inner layer);

• Feature: High dust holding capacity, flexible, washable and reusable after soaking with clean water; no fiber shedding, will not generate secondary particle pollution to clean zones;

• Optional upgrade: Activated carbon composite pre-filter, simultaneously removes coarse dust and odor, volatile organic gas for chemical labs and cosmetic factories.

3. Support Mesh & Edge Sealing

• Double-sided galvanized metal protective mesh to fix fiber media, prevent airflow impact deformation;

• PU foam sealing gasket pre-installed on frame edge, eliminates air bypass leakage between filter and cabinet rack.

Compliance Standards

• Filtration test standard: EN779 (EU G-grade), ASHRAE 52.2 (MERV rating)

• Cleanroom matching: ISO 14644-1 supporting purification system standard

• Material certification: RoHS non-toxic environmental test, CE, ISO9001