Round Flat Duct Take-Off

A round flat duct take-off is a specialized fitting engineered to branch a circular duct line directly from any flat metal surface. Most frequently utilized during ventilation system assembly, this component provides a clean, immediate connection for secondary round duct runs branching off from main rectangular distribution mainlines, mixing chambers, or air handling units.

This component is manufactured from durable galvanized sheet steel, engineered for long-term resistance to atmospheric moisture and operational wear. Automated factory fabrication ensures an exact collar profile, which significantly minimizes localized aerodynamic resistance at the branching node, helping to maintain balanced air pressure across the entire network while eliminating operational turbulence and noise.

Key Benefits and Base Options of the Round Flat Take-Off

• Compact standard flanged execution for even surfaces: The classic take-off features a precise machine-rolled 8–10 mm flange, offering a low-profile and space-saving solution perfectly suited for smooth, uniform attachment planes.
• Heavy-duty square plate mounting for enhanced stability: For projects requiring a larger contact area, the collar can be integrated into a wider square plate base, providing maximum surface room for heavy sealant application, extra corner riveting, and complete coverage over minor installation cut defects.
• Versatile custom material selection under request: To match specific project environments and demanding architectural requirements, the square plate mounting options can be custom-fabricated from high-grade stainless steel, lightweight aluminum, or premium copper.
• Flexible airtightness profiles with integrated gaskets: Available with a factory-fitted double-lipped EPDM rubber gasket to achieve an Airtightness Class D rating on the duct side, or as a standard non-sealed profile for basic extract loops.

Technical Specifications and Installation Guidelines

• Base Material: DX51D grade structural galvanized steel
• Optional Base Materials: Stainless steel, Aluminum, Copper (available for the square plate base configuration)
• Zinc Coating Layer: Z275 (275 g/m²)
• Metal Thickness: 0.5 mm to 0.9 mm (calibrated based on collar diameter)
• Standard Flange Width: 8–10 mm
• Connection Profile: Male (inserts directly into a round duct)
• Quality Standard: Full compliance with EN 1506:2007

Recommended On-Site Installation Practices

• Mark and cut a clean circular opening in the side of the rectangular duct or plenum chamber matching the nominal diameter of the take-off.
• Apply a continuous bead of specialized HVAC sealant onto the contact surface of the flange or square plate base.
• Secure the take-off to the flat surface using standard blind rivets or self-tapping sheet metal screws, ensuring additional corner fixation if utilizing the square plate option.
• Slide the round duct over the circular male collar and seal the external seam with self-adhesive aluminum duct tape to guarantee complete airtightness.