Southwark Metal 21r82020 Duct End Cap R8 20x20

Product Description

The SOUTHWARK METAL 21r82020 is a Model 21 insulated duct end cap rated R8, sized at 20 inches x 20 inches. It is fabricated from hot-dipped galvanized steel conforming to ASTM A653 CS Type B at 26 gauge, providing corrosion resistance in both residential and light commercial duct systems. The end cap features an S-Lock drive-type connection and is compatible with S-cleat installation. HVAC sheet metal technicians and duct installers use this component to seal the terminal end of a rectangular duct run, maintaining thermal efficiency and preventing air leakage at duct terminations.

This end cap is suited for rectangular duct systems requiring a thermally insulated closure. The R8 insulation value makes it appropriate for unconditioned spaces such as attics, crawlspaces, and mechanical rooms where energy code requirements demand higher insulation performance. The 20 x 20 inch face dimension accommodates larger trunk line terminations typical in residential and light commercial forced-air systems. Southwark also offers this Model 21 end cap in R4 and R6 insulation variants for applications with different thermal requirements.

Key Features

• R8 insulation rating for high-performance thermal closure of rectangular duct ends
• 26-gauge hot-dipped galvanized steel per ASTM A653 CS Type B for corrosion resistance
• S-Lock drive-type connection for secure field assembly
• Compatible with S-cleat installation method
• Available in R4 and R6 insulation variants within the same Model 21 product line

Compatibility

Designed as an OEM-style end cap for 20-inch x 20-inch rectangular duct systems using S-Lock drive and S-cleat connections. Compatible with R4, R6, and R8 insulated duct assemblies in the Southwark Model 21 product line.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified sheet metal worker. Shut down the air handling system and verify zero static pressure in the duct before fitting the end cap. S-Lock drive connections should be fully seated and secured with the appropriate S-cleat prior to system restart. Follow local mechanical codes and SMACNA duct construction standards for sealing and insulation requirements in the applicable climate zone.