Southwark Metal 17_22X8-18X8 Trunk Duct Transition 22x8 to 18x8

Product Description

The SOUTHWARK METAL 17_22X8-18X8 is a sheet metal trunk duct transition reducer designed to step down a rectangular duct run from 22 x 8 inches to 18 x 8 inches. Fabricated from hot-dipped galvanized steel, this fitting maintains a consistent 8-inch height while reducing the width by 4 inches, allowing airflow to be managed as the main trunk tapers toward the end of a supply duct system. HVAC installers use tapered trunk transitions to balance static pressure and maintain velocity across longer duct runs. The galvanized steel construction meets SMACNA and ACCA fabrication standards, making it suitable for residential and light commercial forced-air systems.

This transition fitting is used in rectangular sheet metal trunk duct systems where the main supply duct must be reduced in cross-section to account for branch takeoffs along the run. It is a standard component in trunk-and-branch duct layouts found in residential furnace, air handler, and rooftop unit installations. Sheet metal contractors and HVAC technicians install this fitting during new construction or duct renovation projects where proper sizing of the trunk is required for system efficiency and airflow balance.

Key Features

• Reduces trunk duct from 22 x 8 inches to 18 x 8 inches in a single fitting
• Hot-dipped galvanized steel construction for corrosion resistance in conditioned-air applications
• Fabricated to SMACNA and ACCA applicable standards
• Consistent 8-inch height allows straightforward inline installation without offsetting the duct centerline vertically
• Standard sheet metal construction supports field modification, drive-and-cleat, or slip connections

Compatibility

Designed as an OEM-style sheet metal fitting for rectangular trunk duct systems requiring a 22 x 8 inch to 18 x 8 inch transition in residential or light commercial forced-air HVAC installations.

Installation Notes

Sheet metal contractors and licensed HVAC technicians typically install trunk duct transitions as part of duct fabrication or renovation work. Always shut down and de-energize the air handling equipment before working on the duct system. Connections should be sealed with UL 181-listed mastic or metal tape and secured with drive-and-cleat or slip connectors in accordance with SMACNA duct construction standards. Follow local mechanical codes for support spacing and sealing requirements.

Technical Specifications

• Material: Hot-Dipped Galvanized Steel
• Inlet Size: 22 x 8 inches
• Outlet Size: 18 x 8 inches
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 17_22X8-18X8