4-Inch Insulated Chimney Pipe - 18-Inch Length

This 4-inch insulated chimney pipe is an 18-inch fixed length for compatible Selkirk Model HT / Ultra-Temp chimney installations. It gives you a shorter chimney section for layouts where a 24-inch or 36-inch piece would add too much height.

Selkirk's current Ultra-Temp literature lists the 4-inch system to UL 103 Type HT in the United States. The 4-inch chimney uses stainless steel inner and outer walls with 1-inch solid-pack insulation and requires 2 inches of airspace to combustible materials when installed according to the manufacturer's instructions.

18-Inch 4-Inch Chimney Pipe Features

• Inside diameter: 4 inches
• Outside diameter: Approximately 6 inches
• Nominal length: 18 inches
• Selkirk product number: 204018U
• Insulation: 1-inch solid-pack insulation
• Listing: UL 103 Type HT for the 4-inch Ultra-Temp system in the United States
• Clearance: 2 inches of airspace to combustibles when installed per Selkirk instructions
• Connection: Secure twist-lock chimney connection with securing screw
• Manufacturer: Selkirk

Why Choose an 18-Inch Chimney Section?

The 18-inch length is useful for fine-tuning total chimney height without adding a full 2-foot or 3-foot section. It can be combined with other compatible Selkirk 4-inch chimney lengths to build the required system while keeping the number of joints reasonable.

Selkirk notes that installed length is reduced at each joint because the chimney sections overlap when connected. Account for that joint engagement when planning the final chimney height.

Combine With Other 4-Inch Chimney Lengths

• 4-Inch Insulated Chimney Pipe - 12-Inch Length
• 4-Inch Insulated Chimney Pipe - 18-Inch Length
• 4-Inch Insulated Chimney Pipe - 24-Inch Length
• 4-Inch Insulated Chimney Pipe - 36-Inch Length

Related 4-Inch Installation Components

Depending on your chimney route, you may also need the 4-Inch HT Pipe Adapter, 4-Inch Black Ceiling Support, 4-Inch Storm Collar, or 4-Inch Rain Cap.

Read our 4-Inch Stove Pipe Guide for help understanding the difference between connector pipe and insulated chimney pipe. You can also browse all 4-inch chimney pipe and installation accessories.

Installation and Compatibility

Use this chimney section only as part of a compatible Selkirk 4-inch Model HT / Ultra-Temp system and only where permitted by the appliance manufacturer and local authority having jurisdiction. The correct chimney height, supports, firestops, flashing, and clearances depend on the appliance, building, roof configuration, and chimney route.

For current manufacturer specifications and technical literature, see the Selkirk Ultra-Temp chimney information.

If you are unsure which lengths or accessories your installation requires, contact us before ordering so we can help you identify the correct 4-inch components.