A Fresh Air Filter is a
coarse-grade primary filter specifically installed at the outdoor air intake of an Air
Handling Unit (AHU) or Fresh Air Handling Unit (FAHU). Its primary role is to scrub
untreated atmosphere air before it mixes with return air or enters the conditioning
coils.
Key Functions :
- Dust Particle Captured: Captures large outdoor contaminants like
sand, large dust, insects, and soot directly from the intake.
- Coil Protection: Prevents debris from clogging the cooling and
heating coils, which is critical for maintaining heat exchange efficiency.
- First Defence for Cleanrooms: In pharmaceutical or hospital setups
(Grades B, C, and D), a dedicated fresh air filter is often the very first stage in
a multi-stage filtration bank.
|
Feature |
EU-3 (G3) |
EU-4 (G4) |
|
Efficiency |
80% – 90% |
> 90% |
|
Particle Size Target |
Down to 20 microns
|
Down to 10 microns
|
Physical Characteristics :
- Media: Typically made of synthetic non-woven fibres (polyester) or
fiberglass with progressive density to maximize dust-holding capacity.
- Construction: Usually found as pleated panels to increase surface
area or as washable HDPE/Metallic mesh filters for easier maintenance in high-dust
outdoor environments.
- Durability: Often housed in aluminium frames to withstand outdoor
humidity and physical impacts.
