FireFlex 316L Pre-Insulated Stainless Steel Chimney Liner Tee Kit

The FireFlex Pre-Insulated Chimney Liner Tee Kit combines a flexible 316L stainless steel inner liner, factory-applied insulation, and a protective outer liner in one complete chimney relining system. The pre-insulated construction helps simplify installation by eliminating the need to wrap the liner with insulation at the jobsite.

Designed for relining existing masonry chimneys and approved new-construction applications, the flexible liner can navigate bends and offsets while providing a durable pathway for venting combustion gases. Each tee kit includes the liner, chimney-top components, rain cap, and a two-part tee for horizontal appliance connections.

FireFlex Pre-Insulated Chimney Liner Features

• 316L Stainless Steel Inner Liner: The flexible interior liner is manufactured from 0.006-inch 316L stainless steel for corrosion resistance and long-term venting performance.
• Factory-Applied Insulation: A 1/2-inch layer of insulation is installed around the inner liner before shipment, reducing the need for field-applied insulation.
• Protective Outer Liner: The standard aluminum outer liner protects the insulation during shipping, handling, and installation.
• Optional Stainless Steel Outer Liner: A 316L stainless steel outer liner is also available. Call for current pricing and additional product details.
• Flexible Construction: Interlocked and diagonally crimped construction provides the flexibility needed to navigate offsets and bends inside existing masonry chimneys.
• Seven-Ply Seams: Seven-ply seams and 10 corrugations between each seam provide strength while maintaining installation flexibility.
• UL 1777 Listed: The FireFlex chimney liner system is listed to UL 1777 in the United States.
• Lifetime Transferable Warranty: The liner is backed by a lifetime transferable warranty, except when coal or corn is used as fuel.

Sizing Notice: Pre-insulation adds approximately 1 1/2 inches to the liner’s overall outside diameter. Confirm that the chimney flue has enough space for the insulated liner before ordering.

What Is a Pre-Insulated Chimney Liner?

A pre-insulated chimney liner arrives with insulation already installed around the flexible stainless steel liner. A protective outer jacket surrounds the insulation to help prevent damage during shipping and installation.

This construction can reduce jobsite preparation and make it easier to install an insulated liner through an existing masonry chimney. Because the insulation increases the liner’s outside diameter, the chimney flue must be measured carefully before selecting a liner size.

FireFlex Pre-Insulated Liner Specifications

What Is Included in the Chimney Liner Tee Kit?

Each FireFlex Pre-Insulated Chimney Liner Tee Kit includes Fireside Chimney Supply’s EZ Connect components for a complete chimney relining installation.

• FireFlex 316L pre-insulated flexible chimney liner
• Standard top plate with EZ Connect collar
• Optional flue-fit top plate with EZ Connect collar for chimneys with clay flue tiles
• Rain cap with protective screen
• Two-part stainless steel tee
• Removable 10-inch tee snout for the horizontal appliance connection
• Complete installation instructions
• Lifetime transferable liner warranty, subject to warranty terms

EZ Connect Chimney-Top Options

Select the chimney-top configuration that best matches the existing chimney and flue-tile arrangement.

Common Applications

The FireFlex Pre-Insulated Chimney Liner System is designed for relining existing masonry chimneys and may also be used in approved new-construction applications.

• Masonry chimney relining
• Chimneys with bends or offsets
• Appliance installations requiring a tee connection
• Horizontal appliance connections through the chimney wall
• Replacement of deteriorated or damaged flue-liner systems
• Projects where factory-applied insulation can simplify installation

Fuel Compatibility

The 316L stainless steel liner is intended for approved multi-fuel applications. Always confirm liner compatibility, sizing, insulation, and venting requirements with the appliance manufacturer and applicable installation instructions.

Coal and Corn Applications: Fireside Chimney Supply recommends Heavy Wall liners for coal and corn usage. Coal and corn applications are excluded from the lifetime transferable warranty for this liner.

Installation Preparation

Measure the available chimney-flue space before installation. The insulation and outer liner add approximately 1 1/2 inches to the liner’s total outside diameter.

Proper liner diameter, chimney clearance, insulation, appliance connection, and termination must follow the appliance manufacturer’s instructions, FireFlex installation instructions, and applicable building codes.

Pre-Insulated vs. Field-Insulated Chimney Liners

UL 1777 Listing and Warranty

The FireFlex chimney liner system is UL 1777 listed in the United States. Installation must follow the listing requirements, appliance instructions, and the supplied FireFlex installation documentation.

The liner includes a lifetime transferable warranty, subject to the applicable warranty terms. The warranty does not apply when the liner is used with coal or corn fuel.

Why Buy FireFlex From Fireside Chimney Supply?

• 316L stainless steel flexible inner liner
• Factory-applied 1/2-inch insulation
• Protective aluminum outer liner
• Optional 316L stainless steel outer liner
• EZ Connect chimney-top components
• Two-part stainless steel tee with removable 10-inch snout
• Multiple standard and deluxe top-kit options
• UL 1777 listed system
• Complete installation instructions
• Technical support from Fireside Chimney Supply

FireFlex Pre-Insulated Chimney Liner FAQs

How much larger is a pre-insulated chimney liner?

The insulation and protective outer liner add approximately 1 1/2 inches to the inner liner’s nominal diameter. Confirm the available chimney-flue space before ordering.

What is the inner chimney liner made from?

The flexible inner liner is manufactured from 0.006-inch 316L stainless steel.

How thick is the insulation?

The liner includes a factory-applied 1/2-inch layer of insulation.

Why does the liner have an aluminum outer jacket?

The aluminum outer liner helps protect the insulation during shipping, handling, and installation.

Can I order the liner with a stainless steel outer jacket?

Yes. A 316L stainless steel outer liner is available as an optional configuration. Call Fireside Chimney Supply for current pricing and product details.

What comes with the pre-insulated tee kit?

The kit includes the pre-insulated flexible liner, a standard or optional flue-fit top plate with EZ Connect collar, a screened rain cap, a two-part stainless steel tee with removable 10-inch snout, installation instructions, and the applicable liner warranty.

What is the removable tee snout used for?

The removable 10-inch snout provides the horizontal connection between the liner tee and the heating appliance or connector system.

What must be removed before connecting the tee or appliance adapter?

Remove approximately 4 inches of the outer liner and insulation before attaching an appliance adapter, two-part flex tee, or pulling cone.

Is the FireFlex chimney liner UL listed?

Yes. The FireFlex chimney liner system is listed to UL 1777 in the United States.

Can this liner be used with coal or corn?

Fireside Chimney Supply recommends Heavy Wall liners for coal and corn applications. Coal and corn usage is excluded from the lifetime transferable warranty for this liner.

Can the liner be installed in a chimney with offsets?

The flexible construction is designed to navigate bends and offsets commonly found in existing masonry chimneys. Confirm the chimney dimensions and installation path before ordering.

Can this liner be used in new construction?

The supplied product information states that the liner may be used for existing chimney relining or new construction. The installation must comply with the FireFlex instructions, appliance requirements, listing, and applicable building codes.

What is the difference between the standard and clay-tile top kits?

The standard top plate is designed for flat chimney-top installations. The flue-fit or clay-tile top option is designed to fit installations with an existing clay flue tile.

Installation Instructions

Review the complete instructions before sizing, ordering, or installing the liner.

Download the FireFlex Chimney Liner Installation Instructions