Selkirk 18KMR6 Flex Duct 18 in R-6 Foil Jacket 25 Ft

Product Description

The SELKIRK 18KMR6 is an 18-inch flexible HVAC duct designed for large-diameter supply and return air runs where both thermal efficiency and routing flexibility are required. It features an R-6 insulation rating and a foil jacket that limits heat gain and loss along the duct run. At 18 inches in diameter, this duct is sized for high-airflow commercial and large residential applications. Each section ships in a 25-foot length. HVAC contractors and mechanical installers use this product when code or project specifications call for R-6 insulated flex in trunk or branch distribution systems.

This flexible duct is suited for commercial HVAC systems and large-scale residential installations where 18-inch diameter runs are required on supply or return plenums. The foil jacket construction holds up in attic, crawlspace, and mechanical room environments. The 25-foot length reduces the number of connections needed on long runs, which limits air leakage points and simplifies layout. Applications include air handler connections, VAV box feeds, and large branch distribution runs in light commercial construction.

Key Features

• R-6 insulation rating reduces heat gain and loss in unconditioned spaces
• Foil jacket provides a durable outer barrier suitable for attic and mechanical room installs
• 18-inch diameter supports high-volume airflow in commercial and large residential systems
• 25-foot section length minimizes the number of field connections on long duct runs
• Flexible construction allows routing around structural obstructions without rigid fittings

Compatibility

Designed as an OEM-style flexible duct replacement or new-installation component for 18-inch diameter supply and return air distribution systems requiring R-6 insulation performance.

Installation Notes

Flexible duct of this diameter is typically installed by licensed HVAC mechanics or sheet metal contractors working under applicable mechanical codes such as SMACNA standards and local IMC requirements. Shut down and lock out the air handling unit before connecting or repositioning flex duct. Avoid sharp bends and compressed sections, as both conditions reduce effective airflow and can void insulation performance. Secure all connections with approved clamps and mastic or UL-listed tape rated for flexible duct applications.

Technical Specifications

• Diameter: 18 inches
• Insulation Rating: R-6
• Jacket Type: Foil
• Length: 25 feet

Standard Information

• Brand: SELKIRK
• Manufacturer Part Number: 18KMR6