Southwark Metal 35A_4IN Trunk Duct Reducer 4 in

Product Description

The SOUTHWARK METAL 35A_4IN is a cut-in sheet metal trunk duct reducer designed for use in forced-air HVAC distribution systems. Fabricated from hot-dipped galvanized steel, this reducer allows technicians to branch or reduce airflow from a main trunk duct without cutting the duct out of service in sections. The hot-dip galvanizing process provides corrosion resistance suited to both conditioned and unconditioned spaces such as attics, crawlspaces, and mechanical rooms. Licensed HVAC installers and sheet metal contractors are the primary trade installing this fitting.

This trunk duct reducer is used in residential and light commercial duct systems where a main supply trunk must be reduced in size to match downstream duct sizing or to add a branch takeoff. The cut-in design allows field installation into an existing trunk run, making it well suited for retrofit and service work as well as new construction roughing. The 4-inch size fits standard sheet metal duct configurations common in residential forced-air systems.

Key Features

• Hot-dipped galvanized steel construction for corrosion resistance in attic, basement, and crawlspace environments
• Cut-in design enables installation into existing trunk duct runs without full section removal
• 4-inch nominal size for standard residential duct branch connections
• Meets ACCA and SMACNA applicable standards for sheet metal duct fittings

Compatibility

Designed as an OEM-style sheet metal fitting for use in residential and light commercial forced-air trunk duct systems requiring a 4-inch cut-in reducer connection.

Installation Notes

Installation should be performed by a licensed HVAC technician or sheet metal contractor in accordance with SMACNA duct construction standards and local mechanical codes. Shut down and de-energize the air handling system before cutting into any live trunk duct. Secure all connections with appropriate sheet metal screws and seal joints with UL 181-rated tape or mastic to maintain system pressure integrity. Do not install in applications where fitting size or gauge does not match the existing trunk duct specifications.

Technical Specifications

• Material: Hot-Dipped Galvanized Steel
• Type: Cut-In
• Nominal Size: 4 inches
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 35A_4IN