What a Primary Filter Is For
Primary (pre) filters sit first in the bank. They capture the bulk of coarse dust so the more expensive medium or HEPA stage lasts longer and stays clean.
Common Types
- Panel filters – cardboard or metal frame, synthetic or glass media; cheapest, for G2-G4.
- Pocket / bag filters – several deep pockets of synthetic media; larger area, lower ΔP, G3-G4 and into F5.
- Roll / automatic filters – continuously fed media for very dusty intakes.
- Washable metal mesh – reusable coarse screen for grease/intake hoods.
Typical Specifications
| Class | Arrestance | Initial ΔP | Frame |
|---|---|---|---|
| G3 | 80-90% | 25-40 Pa | Cardboard / metal |
| G4 | ≥ 90% | 30-45 Pa | Cardboard / metal |
Selection Checklist
- Match frame size to the existing holding frame (592×592 mm and 495×495 mm are common).
- Pick G4 for most HVAC; G3 where dust is very heavy and cost rules.
- Confirm max operating temperature (synthetic ~70-80 °C; glass higher).
- Choose pockets over panels when space allows lower ΔP.
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Model Range & Specifications
| Model | EN 779 class | ISO 16890 equivalent | Arrestance | Media & frame | Typical initial ΔP | Recommended final ΔP |
|---|---|---|---|---|---|---|
| 26YC-PF-G1-595 | G1 | ISO Coarse 40–50% | 50–65% | Synthetic media, cardboard frame, 46 mm | 25–40 Pa | 150 Pa |
| 26YC-PF-G2-595 | G2 | ISO Coarse 50–60% | 65–80% | Synthetic media, cardboard frame, 46 mm | 30–45 Pa | |
| 26YC-PF-G3-595 | G3 | ISO Coarse 60–70% | 80–90% | Synthetic / PET media, cardboard or galvanized frame, 46 mm | 35–55 Pa | |
| 26YC-PF-G4-595 | G4 | ISO Coarse 70–80% | 90–95% | Synthetic / PET media, galvanized frame, 46 mm | 45–70 Pa | |
| 26YC-PK-G4-600 | G4 | ISO Coarse 70–80% | 90–95% | Synthetic bag, 5–6 pockets, galvanized header, 360–600 mm deep | 40–60 Pa | 150 Pa |
Standard face size 595 × 595 mm (592 × 592 mm available); rated face velocity 0.9–1.0 m/s; max continuous temperature 80 °C for synthetic media. Custom sizes, aluminium / stainless frames and washable PET media on request — send us your AHU drawings for a free selection.
Frequently Asked Questions
What is a primary filter used for?
It captures coarse dust and protects the more expensive downstream filter, extending the life of the whole filtration bank.
Should I choose a panel or pocket G4 filter?
Panel filters are cheap with lower capacity, while pocket filters hold more dust and suit heavier or continuous duty.
How often should G3 or G4 filters be replaced?
Typically every three to six months, but the interval depends on local dust load and the measured pressure drop.
Can primary filters be washed and reused?
Some synthetic and metal-mesh types are reusable, but most media primary filters are disposable and should be bagged out.
