InnoFlue® Flex

Material & Construction

InnoFlue® Flex uses industry leading, flame retardant polypropylene technology to construct single wall, gasketed, flexible vent pipes and accessories. InnoFlue® Flex’s dynamic special gas vent product line provides superior corrosion protection throughout. Lightweight polypropylene eliminates installation fatigue associated with most common venting materials, making it easy. The flexible properties of the Vent Length allow for the rapid lining of chimneys, b-vents, and other chases with offsets up to 45°. InnoFlue® is tested by Intertek and listed to UL-1738 and ULC-S636.  InnoFlue® polypropylne special gas vent systems are zero clearance to combustibles.

3″ and 4″ diameter Flex Vent Lengths have rigid sections every 2 feet. These rigid male sections can be inserted into any InnoFlue® Single Wall socket and allow for the easy transition between Single Wall and Flex. Once Centrocerin (installation lubricant) has dried the gaskets provide firm junctions between components.

InnoFlue® Flex is used to vent individual appliances. InnoFlue® Flex is commonly combined with InnoFlue® Single Wall but can also be combined with InnoFlue® Concentric. For more information on system configurations, visit the InnoFlue® Flex Solutions page.


Diameters: 2″ (60mm), 3″ (80mm), 4″ (110mm)

Available Lengths:

2" Diameter 3" Diameter 4" Diameter
150' Length 150' Length 80' Length
25' Kit 25' Kit 25' Kit
35' Kit 35' Kit 25' Kit
50' Kit 40' Kit 40' Kit
  50' Kit 50' Kit


Suitable for U.S. Category II and IV or Canadian Type Gas Vent BH, Class II heating equipment:
  • Gas Fired – 230°F (110°C) Max Flue Gas Temp
  • Oil Fired – 248°F (120°C) Max Flue Gas Temp
  • Appliance Type: Condensing Boilers, Furnaces, Tankless Water Heaters & Tanked Water Heaters


  • 2+mm thick rigid polypropylene
  • EPDM Gaskets with an H1 pressure rating (5000Pa).
  • PPs gray composition up to 4″ (110mm) diameter.

Features & Benefits


  • Handles up to 45° degree offsets
  • Multiple flex liners can share a single chase

Continuous Lengths up to 150′

  • Prevents risk of joint failure
  • Eliminates cure time, speeding up installations


  • Product can be hand carried eliminating the need for lifts

3" and 4" have rigid sections Every 2′

  • Rigid sections incorporated in 3″ and 4″ diameters allow Flex to fit into any Single Wall Vent Length or fitting.
  • Limits waste to a maximum of 2′


Components should be stored in a clean, covered, dry environment in their original packaging. InnoFlue® Flex should be stored above 32°F (0°C).

Health and Safety

For more information on the health and safety benefits of using InnoFlue®, please view our Health and Safety page. Where installation of a InnoFlue® involves working at a height, a full risk assessment must be conducted and appropriate safety measures put into place.


Installation of InnoFlue® does not require any special tools. Centrotherm recommends that the material temperature is not less than 32°F (0°C) during installation.


Appliance Start-Up

Once InnoFlue® installation is complete the heating system and flue should be commissioned following the boiler manufacturer’s instructions. There is no cure time or wait time required.