Southwark Metal 55NC_20IN Round Duct End Cap 20 Inch

Product Description

The SOUTHWARK METAL 55NC_20IN is a plain, round sheet metal duct end cap designed to seal the open end of a 20-inch diameter round duct section. Constructed from hot-dip galvanized steel, this cap provides a durable, corrosion-resistant closure for HVAC duct systems. The no-crimp design allows it to slip over standard round duct ends without requiring additional forming. It is installed by HVAC technicians during system commissioning, seasonal shutdowns, or when capping unused duct branches in residential and light commercial applications.

This end cap is suited for round sheet metal ductwork in forced-air HVAC systems. Its 20-inch diameter makes it appropriate for main trunk terminations or large branch runs where a clean, secure seal is needed. Fabricated to meet ACCA and SMACNA standards, it fits into standard low-pressure duct system installations. HVAC sheet metal mechanics and installers will find this cap useful during new construction, renovation, or system modification work where duct openings must be closed off cleanly.

Key Features

• Hot-dip galvanized steel construction for corrosion resistance in HVAC environments
• 20-inch diameter round profile fits standard round duct ends
• Plain no-crimp design for straightforward installation without additional forming
• Fabricated to ACCA and SMACNA applicable standards
• Provides a clean, secure closure on open duct terminations

Compatibility

Designed as an OEM-style sheet metal fitting for standard 20-inch diameter round duct sections in residential and light commercial forced-air HVAC systems built to SMACNA and ACCA ductwork specifications.

Installation Notes

Installation is typically performed by a licensed HVAC technician or sheet metal mechanic. Power down the air handling system and confirm airflow has stopped before fitting the cap over the open duct end. Sheet metal screws and foil-backed duct tape or mastic sealant are commonly used to secure and seal the cap per SMACNA installation guidelines. Wear appropriate gloves when handling cut sheet metal edges to avoid injury.

Technical Specifications

• Material: Hot-Dip Galvanized Steel
• Duct Diameter: 20 inches
• Shape: Round
• Crimp: None (Plain)
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 55NC_20IN