Pre-filters (also known as
primary filters) serve as the first stage of filtration. Their main purpose is to
capture large airborne particles before the air reaches more sensitive and expensive
components, such as cooling coils or high-efficiency HEPA filters.
Essential first-stage filtration to protect downstream HEPA filters and maintain AHU
cleanliness.
EU-3 (G3 class):
- Efficiency: Traps 80–90% of synthetic test dust.
- Target Particles: Designed for particles approximately 10
microns or larger.
- Typical Use: Medium-level pre-filtration for simple
ventilation in factories, or as a basic first stage in commercial AHUs.
Primary filtration at Fresh Air Intake.
EU-4 (G4 class):
- Efficiency: Traps >90% of synthetic test dust.
- Target Particles: Effective for particles around 3-5
microns.
- Typical Use: Higher-level pre-filtration required for
stricter environments like hospital cleanrooms, laboratories, pharmaceutical
facilities, or paint booths. Intermediate filtration stage in AHUs.
Technical Specifications
- Filter Media: Typically made of non-woven synthetic fibres
(polyester or polypropylene), HDPE, or fiberglass.
- Structure: Common designs include pleated panels (to increase
surface area), pocket/bag filters, or simple flat pads.
- Frame Material: Usually constructed from Aluminium, or Stainless
Steel (SS 304) for durability and moisture resistance.
