DuraVent 4"-8" Inner Diameter Reducer Type B Gas Vent

Size: 4"

Estimated Arrival: Between and . (To All Contiguous States)

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DuraVent is the premier company in the venting industry. With a broad range of engineered venting products, DuraVent has earned its reputation as the industry leader by offering innovative, safe, and professional products for the HVAC and Hearth markets.

Type B Gas Vent DuraVent's innovative system for a lock-tight connection for Type B Gas Vent is called DuraLock. See the alignment indicators meet; feel the ends grasp together; hear the snap as the connection firmly locks into place. 

Rugged Construction
Strong, durable galvanized steel outer pipe has internal spacing beads to assure a uniform insulating air space between pipe walls. Each end is die-formed to assure uniform sizing for strong, easy-to-connect joints. In Canada, some lengths are available in galvalume steel outer pipe. 

Assured Safety
The double wall (pipe within a pipe) construction with its built-in air space, provides permanent insulation and keeps the inner pipe hot and the outer pipe relatively cool. This construction creates quick, strong vent action reducing condensation in the pipe and overheating of nearby enclosure surfaces.

Fully Tested and Listed
DuraVent Model BV and BVO Type B Gas Vent have been tested and listed per UL 441 for installation as Type B and BW gas vents. These can be installed in single and multi-story buildings in accordance with the standards of NFPA 54 and NFPA 211.



  • One step only
  • For USA only



  • DuraVent’s Type B Gas Vent system. Use with natural gas or liquid propane Category I and draft hood equipped appliances, and appliances tested and listed to use Type B Gas Vent.
  • Applications include natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications.


Materials and Construction

  • Round Type B Gas Vent 3″ – 8″ and Oval 4″ – 6″: Aluminum .012″ inner wall, galvanized .018″ outer wall. 

  • Round Type B Gas Vent 10″ – 18″: Aluminum .014″ inner wall, galvanized .018″ outer wall. DuraLock® feature 10″ and larger diameters.

  • Round Type B Gas Vent 20″ – 30″: aluminum .023″ inner wall, galvanized .018″ outer wall. DuraLock® feature 10″ and larger diameters.



Model STEP
4BVR3 4" x 3"
5BVR4 5" x 4"
6BVR5 6" x 5"
7BVR6 7" x 6"
8BVR4 8" x 7"
Clearances 1" to combustibles in single and multi-family dwellings
Listings UL Listed to UL 441
Warranty Limited lifetime warranty

 Typical Installations

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





Safety Information: CA Prop 65 Warning