Southwark Metal 17_24X8-20X8 Trunk Duct Transition 24x8 to 20x8

Product Description

The SOUTHWARK METAL 17_24X8-20X8 is a sheet metal trunk duct transition reducer designed to step down rectangular ductwork from a 24 x 8 inch opening to a 20 x 8 inch opening. Fabricated from hot dip galvanized steel, it delivers corrosion resistance suited for residential and light commercial forced-air HVAC systems. The taper runs to one side, keeping the opposite face flat for flush mounting against ceilings, joists, or duct chases. This fitting is installed by licensed HVAC technicians and sheet metal contractors during duct fabrication, system balancing, or trunk line modifications. It meets ACCA and SMACNA standards, making it appropriate for jobs requiring documented compliance.

This transition reducer is used wherever a rectangular trunk line needs to reduce in width while maintaining a consistent 8 inch height. Typical applications include residential forced-air supply trunk systems where airflow is being redistributed along a duct run, or where a branch point requires a reduction in main trunk cross-section. The single-side taper allows the fitting to sit flush on one plane, which is useful in tight ceiling spaces or when the duct run must stay aligned to one edge of a joist bay.

Key Features

• Transitions rectangular duct from 24 x 8 inches to 20 x 8 inches in a single fitting
• Hot dip galvanized steel construction for corrosion resistance in conditioned and unconditioned spaces
• Tapered to one side for flush-wall or flush-ceiling duct alignment
• Compliant with ACCA and SMACNA fabrication standards
• Consistent 8 inch height maintained across both ends for simplified duct system layout

Compatibility

Designed as an OEM-style sheet metal fitting for rectangular trunk duct systems requiring a 24 x 8 inch inlet and a 20 x 8 inch outlet connection.

Installation Notes

Installation is performed by licensed HVAC technicians or sheet metal contractors following SMACNA duct construction standards. Secure the fitting to adjoining duct sections using sheet metal screws and seal all joints with UL 181-rated mastic or foil tape to prevent air leakage. Shut down the air handling unit and de-energize the system before making any duct connections. Support the fitting per local mechanical code requirements to prevent stress on the duct joints.

Technical Specifications

• Material: Hot Dip Galvanized Steel
• Inlet Size (Size A): 24 x 8 inches
• Outlet Size (Size B): 20 x 8 inches
• Taper Type: Tapered to One Side
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 17_24X8-20X8