Southwark Metal 55_4IN Duct Tee End Cap 4 Inch

Product Description

The SOUTHWARK METAL 55_4IN is a 4-inch diameter sheet metal duct tee end cap designed to terminate open tee ends in low-pressure residential and light commercial HVAC duct systems. Fabricated from hot dip galvanized steel, it resists corrosion in both supply and return air applications. The crimped end allows the cap to slip over standard round duct fittings and lock in place without additional fasteners in most installations. HVAC sheet metal mechanics and duct fabricators use this cap to close unused branch openings on trunk-and-branch and radial duct systems, maintaining system static pressure and preventing uncontrolled air loss.

This cap is suited for 4-inch round duct assemblies in residential forced-air heating and cooling systems. It seals off tee branch ports during initial installation or when a branch is decommissioned or rerouted. The crimped profile seats securely against the outer diameter of standard 4-inch round duct collars and tee fittings, making it a common stock item for duct fabrication shops and service vans. Installers working with trunk-and-branch layouts will recognize this as a standard closure fitting for balancing or capping branch runs.

Key Features

• 4-inch diameter to match standard round duct and tee fittings
• Hot dip galvanized steel construction for corrosion resistance
• Crimped end profile for secure slip-fit installation over duct collars
• Meets ACCA and SMACNA applicable standards for duct construction
• Closes unused tee branch openings to maintain system static pressure

Compatibility

Designed as an OEM-style sheet metal duct fitting for use with standard 4-inch round duct tee fittings in residential and light commercial forced-air HVAC systems built to SMACNA and ACCA duct construction standards.

Installation Notes

Installation is performed by licensed HVAC technicians or sheet metal mechanics. Shut down the air handling unit and isolate the duct section before fitting the cap to prevent pressure-related displacement during installation. The crimped end should be seated fully over the tee branch collar; apply duct mastic or UL-listed foil tape at the seam per SMACNA sealing class requirements for the system pressure class. Do not substitute this fitting in high-pressure or medium-pressure duct systems beyond the fitting's rated pressure class.

Technical Specifications

• Size: 4 inches diameter
• Material: Hot Dip Galvanized Steel
• End Type: Crimp
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 55_4IN