Southwark Metal PH74128 Duct Boot 4x12x8 in 30 Gauge

Product Description

The SOUTHWARK METAL PH74128 is a straight rectangular-to-round sheet metal duct boot designed to transition airflow from a rectangular trunk or branch duct to a round collar for register termination. The body is fabricated from ASTM A653 CS Type B G40 hot dip galvanized steel at 30 gauge, with a heavier 28 gauge collar for added rigidity at the connection point. The flat back configuration suits installations where the boot seats flush against a floor deck or wall framing. This fitting is installed by HVAC technicians during new construction and retrofit duct system work.

This duct boot is sized with a 4 x 12 inch rectangular opening on the A end and an 8 inch round collar on the B end. It is used in residential and light commercial forced-air HVAC systems where a floor, wall, or ceiling register terminates a supply or return air duct run. The straight orientation simplifies installation in tight joist bays or stud cavities where offset fittings are not required.

Key Features

• Straight rectangular-to-round configuration transitions 4 x 12 inch duct to 8 inch round collar
• 30 gauge ASTM A653 CS Type B G40 hot dip galvanized steel body resists corrosion in conditioned and unconditioned spaces
• 28 gauge galvanized collar provides extra stiffness at the round duct connection
• Flat back design seats flush for floor or wall register applications
• Manufactured to ACCA, SMACNA, and NATE applicable standards

Compatibility

Designed as an OEM-style sheet metal fitting for residential and light commercial forced-air duct systems requiring a straight rectangular-to-round register boot transition.

Installation Notes

Installation is performed by licensed HVAC technicians or sheet metal workers following SMACNA duct construction standards. Secure the rectangular end to the branch duct with sheet metal screws and seal all joints with UL-listed duct mastic or metal-backed tape per local mechanical code requirements. Connect the round collar to the supply or return duct using an appropriately rated duct connector. Power down the air handling system before making any duct connections.

Technical Specifications

• Size A (Rectangular Opening): 4 x 12 inches
• Size B (Round Collar): 8 inches
• Body Material Thickness: 30 Gauge
• Collar Material Thickness: 28 Gauge
• Material: ASTM A653 CS Type B G40 Hot Dip Galvanized Steel
• Configuration: Straight, Rectangular to Round, Register
• Feature: Flat Back
• Applicable Standards: ACCA, SMACNA, NATE

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: PH74128