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TDC Rectangular Ductwork and Fittings

The Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) recommended TDC rectangular duct is a 4-bolt system with a difference. Instead of cutting, assembling and installing a separate flange onto the ductwork, the TDC flange is roll-formed directly onto the rectangular duct. This provides a solid metal connection that reduces leakage which is why the TDC system is the best for minimum leakage application. A TDC assembly instruction manual is available upon request.

Slip and Drive Rectangular Ductwork and Fittings

Slip and drive rectangular ductwork is the traditional system using s-slip and drive connectors.

Raw Rectangular Ductwork and Fittings

Raw rectangular ducts are fabricated for proprietary duct connection systems.

Rectangular Duct Fittings

Sheet Metal Connectors, Inc. manufactures rectangular duct fittings in most sizes and configurations. Fittings are manufactured on our state of the art fabrication equipment. All rectangular duct fittings are fabricated with stiffening beads on duct sizes 19” wide and larger which have more than 10 square feet of unbraced panel. Rectangular duct fittings shall be beaded unless the duct will have an insulation covering or an acoustical liner. This requirement is applicable to 20 gauge or less in thickness and 3” W.G. or less. Most rectangular duct fittings are fabricated with Pittsburgh seams. Duct fittings are available completely assembled with all accessories (reinforced, vane and rail, etc.) installed. Fittings are also available knocked down to reduce shipping and handling costs.

Turning Vane and Rail

SMC manufactures several types of turning vane and E-Z rail. Turning vane and E-Z rail are recommended for square throat elbows and tees. When using turning vane and E-Z rail performance is greatly enhanced in the HVAC duct system. Test data is available upon request.

Transverse Joint and Intermediate Reinforcement

SMC manufactures many different types of reinforcement. SMC’s most popular types are as follows:
Tie Rod Reinforcement: threaded inserts installed into each end of thin wall (emt) conduit. These are installed internally at both the joint and/or intermediate duct spacing.
R-Angle Reinforcement: roll formed pre-punched angle iron reinforcement. See chart below.

Insulation

Sheet Metal Connectors, Inc. duct liner shall be of the specified material, thickness, and density of the contractor's request. The rectangular duct dimensions shall be increased as necessary to compensate for linear thickness. All sizes shall be listed using outside dimensions. Each layer of duct liner shall be attached with a minimum of 90% coverage of adhesive at the liner contact surface area. Pin placement is shown in the chart below.


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ASTM C 1071 Type 1 Replaces HH-I-545B Type 1