🧱 Introduction
Choosing the right duct connection methods is essential for a durable, airtight, and efficient HVAC system.
At Pacific Duct, we support contractors by fabricating rectangular and round duct systems compatible with TDC, Slip & Drive, Ductmate 35, and various round duct joining methods.
Understanding these options helps ensure smooth installations and long-term system performance.
🔹 Rectangular Duct Joining Methods
1. TDC (Transverse Duct Connector)
The TDC flange system is one of the most popular rectangular duct connection methods in commercial HVAC fabrication.
- Fabricated directly into the ductwork for added strength and alignment
- Reduces material waste and improves installation efficiency
- SMACNA-compliant for reliable field performance
✅ Best for: Medium to large rectangular duct systems
📎 → View Pacific Duct’s TDC submittal documentation
2. Slip and Drive
The Slip & Drive method is simple, cost-effective, and quick to install — ideal for smaller ducts.
- Slip joints secure the long sides; drive cleats lock the short sides
- Allows flexibility during installation
- Moderate air-sealing performance
✅ Best for: Low- to medium-pressure systems where cost efficiency matters
3. Ductmate 35 Flange System
The Ductmate 35 system provides a gasketed, bolted connection that ensures airtight performance and quick field assembly.
- Offers superior sealing and minimal leakage
- Uses corners, cleats, and gaskets for professional results
✅ Best for: Projects requiring high air-tightness or modular assemblies
🌐 → Learn more at Ductmate Industries
🔸 Round Duct Joining Methods
1. Slip-On Couplers
A slip-on coupler is a straight piece of duct that slides over the ends of two sections to create a smooth connection. Also know as Spiral Couplings.
- Common for exposed spiral ductwork where appearance matters
- Provides a clean, seamless finish
✅ Best for: Aesthetic or visible duct installations
2. Crimping
Crimping uses a hand or power crimper to add small ridges to one end of a duct, allowing it to slide easily into another piece.
- Simple and quick for field adjustments
- Creates a secure, tapered fit
✅ Best for: Light-gauge round ducts and flexible connections
3. Beaded Couplings
Beaded couplings are connectors that fit inside round duct sections, creating a snug, reinforced joint.
- The bead helps prevent slippage and air leaks
- Designed for ducts of the same diameter
✅ Best for: Tight spaces or when internal connections are preferred
4. Dura Flange Rings
Dura Flange Rings provide a flanged, bolted connection for round ductwork, offering structural integrity and a reliable seal.
- Often used in high-pressure or industrial systems
- Compatible with gasket materials for airtight performance
✅ Best for: Heavy-duty HVAC applications and large duct sizes
🧰 How to Choose the Right Duct Connection Method
Selecting the correct duct connection method depends on:
- System pressure class and leakage requirements
- Project size, installation speed, and aesthetic needs
- Maintenance or accessibility requirements
At Pacific Duct, we fabricate all major connection types — TDC, Slip & Drive, Ductmate 35, Slip-On Couplers, Beaded Couplings, Crimping, and Dura Flange Rings — to match your project’s specific needs.
🚀 Partner with Pacific Duct
As a single-source duct supplier, Pacific Duct simplifies large HVAC projects by providing complete duct systems, fittings, and accessories — all under one roof.
📞 Call us at 909-635-1335
🌐 Visit www.pacificduct.com to request a quote or learn more about our duct connection options.