Flanges PF

PF Circular Flanges

Cost effective circular flange for small duct diameters  (80 up to 200 mm)
Pressed flange which can be swaged into the duct. That way the duct inner surface remains free of any projections (for dust removal, wood chips transport and other similar applications requiring a smooth inner duct surface).
Alternative fastening methods: spot welding, self-tapping screws or blind rivets
Assembly through SS Joining Clips.

  1. Duct wall
  2. PF flange
  3. The ends are tapered to facilitate the insertion of the flange
  4. SS joining clip

Suitable Ducts

For inner-duct diameters from 80 up to 200mm.
In-between diameters are not available.

Suitable duct types: spirally wound ducts, longitudinal seam ducts and fittings.

Not suitable for ducts and fittings with turned-out edges and ducts with stiffening ribs.

Fixation Methods

Fastening in the duct through blind-rivets and swaging.

Screws are less recommended, as they protrude inside the duct, hindering the air-flow and the cleaning operations, and could be the cause of leakages.

Spot welding only possible when the flange and duct are an exact fit (low tolerances).


The metal lip of the flange automatically seals the connection. When correctly installed the air-tightness class C (DIN EN 12237) or ATC 3 (DIN EN 16798-3) are reached. See also ZI-702.

The flanges stiffen the ducts and help maintaining their round shape. They also improve the resistance of the ducts under negative pressures. Ducts should nevertheless be strong enough by themselves and resist the required pressures (+ or -) without taking the flanges into account.

No gap, as the flange is a pressed continuous ring.

Available in galvanized steel and stainless steel V2A (1.4301 ASTM 304) upon request. Cracks can appear on the stainless steel versions. They are unavoidable and consequently no reason for a claim. Please also refer to ZI-101


A sealant must be applied.
In-between diameters are not possible

List of Products & Prices

Installation Instructions

Texts for Tenders




CAD Drawings

Made by METU in Germany