Southwark Metal 17_18X8-14X8 Trunk Duct Transition 18x8 to 14x8

Product Description

The SOUTHWARK METAL 17_18X8-14X8 is a sheet metal trunk duct transition reducer designed to step down a rectangular duct from 18 inches x 8 inches to 14 inches x 8 inches. Fabricated from hot dip galvanized steel, this fitting delivers corrosion resistance suited to the long service life expected in commercial and residential forced-air systems. The taper runs to one side, maintaining a flush surface on the opposite face — a common requirement when aligning trunk runs against a joist, beam, or other structural element. HVAC sheet metal installers and ductwork contractors use this fitting to reduce airflow cross-section within a trunk system while keeping the run in-line and properly supported.

This trunk transition is used in forced-air HVAC ductwork systems where a rectangular main trunk must reduce in size as supply branches are taken off along its run. It is appropriate for both new construction and retrofit applications in residential and light commercial installations. The one-sided taper is particularly useful in tight ceiling or crawlspace installations where one face of the duct must remain flush with a fixed reference surface. Fabrication meets ACCA and SMACNA standards, making it compatible with systems designed and installed under those guidelines.

Key Features

• Reduces trunk duct from 18 inches x 8 inches (Size A) to 14 inches x 8 inches (Size B)
• Hot dip galvanized steel construction provides durable corrosion resistance
• Taper runs to one side, keeping one face flat for flush installation against structure
• Meets ACCA and SMACNA applicable standards for duct fabrication
• Designed for rectangular trunk duct systems in forced-air applications

Compatibility

Designed as an OEM-style sheet metal fitting for rectangular trunk duct systems fabricated and installed to ACCA and SMACNA standards in residential and light commercial forced-air HVAC applications.

Installation Notes

Installation should be performed by a qualified HVAC technician or sheet metal contractor. Power down the air handling unit and verify the system is de-energized before working in the duct system. Secure the fitting to adjacent duct sections using sheet metal screws and seal all joints with UL 181-rated mastic or foil tape in accordance with local mechanical codes. Handle cut edges carefully — galvanized sheet metal edges are sharp and require appropriate gloves and eye protection.

Technical Specifications

• Size A (Inlet): 18 inches x 8 inches
• Size B (Outlet): 14 inches x 8 inches
• Material: Hot Dip Galvanized Steel
• Type: Tapered to One Side
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 17_18X8-14X8