Made from super-ferritic stainless steel. Corrosion resistant. Manufactured with a sure-seal locking seam for superior strength and flexibility. The smooth inner-wall provides for no output reduction, allowing for full appliance efficiency, ease of cleaning and regular maintenance. The smooth inner wall optimizes gas flow, minimizes back pressure, and facilitates condensate management. Only flexible chimney liner listed to UL 1738 standard. 

FasNSeal® Flex is for use with natural gas or propane Categories II, III and IV appliances or Canada’s Type BH Gas Vent Systems, having a maximum rated operating temperature of 480°F and a maximum positive pressure of 15” water column. FasNSeal® can be used on a wide range of applications, including: high efficiency gas boilers, furnaces, booster heaters, pool heaters, water heaters, unit heaters, or tankless water heaters.

Materials and Construction
Single strip double layer super-ferriticstainless steel (totalling .010″).

FasNSeal® Flex 3″-12″

UL Listed to UL 1738 and UL 1777 and ULC S636.

Refer to our Typical Venting Installation drawings to select the appropriate component parts for your installation.

More Typical Installations:

Installation Key
1Rain Cap
2Storm Collar
3Variable Pitch Roof Flashing
4Vent Length
5Adjustable Vent Length
6Firestop/Flat Flashing
7Horizontal Drip Tee
9Universal Condensate Drain
10Appliance Adapter
11Top Plate*
12Male Flex Adaptere
13FasNSeal Flex
14Female Flex Adapter
15Standard Tee

Commercial Applications

Commercial projects may require custom parts and unique system designs. DuraVent offers complete project assistance:

  • Engineering Services: Personalized system design services offer comprehensive CAD submittal drawing and complete bills of materials.
  • Custom Parts: If your project requires innovative solutions, contact DuraVent for custom parts that meet your specific project needs.
  • FasNSeal W2: FasNSeal W2 is the ideal choice for commercial applications where there is a need for low clearances to combustibles.
  • Up to 16” Vent Diameters: Many commercial applications require large diameter systems due to the units size and output. Large diameters are available in single and double wall, featuring FasNSeal’s triple lipped directional gaskets and built-in locking band which provides a safe and convenient installation.