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    DuraVent Type B Venting Installation Guide

    DuraVent Type B Venting Installation Guide

    Simpson Dura-Vent's Type B Gas Vent system is for 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 for a wide range of applications, including: natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications.

    Simpson Dura-Vent's Type B Gas Vent systems are UL Listed to UL 441 and UL 1777 (MH6357). ULC Listed to ULC S605 (CMH1276 & CMH1407).

    DuraVent Type B Venting Installation Guide
    DuraVent Type B Venting Installation Guide

    How Size and Height Affect Stove Performance

    The amount of heat the vent gases lose as they flow determines how much condensation will occur and how strong the draft will be. To control the heat loses, proper selection of venting materials is of vital importance.

    A Type B Gas Vent Sizing Handbook is available to assist you with the proper installation. Click HERE to view online.

    Vent Termination Chart

    Using listed Type B Gas Vent caps may terminate in accordance with this table.

    DuraVent Type B Venting Installation Guide

    Gas Vent Specification Chart

    DuraVent Type B Venting Installation Guide


    1. Clearance to combustibles is the air space between vent and combustibles.

    2. Maximum height varies with equipment over 50", for taller applications refer to SDV sizing handbook 2. (L202). 14"-16" Require screws.

    3. When oval is used on wall furnaces, minimum height required from bottom of furnce to cap is 12", minimum 16" stud space.

    4. Limited by sizing tables.

    5. 18" pipe OD is one inch larger than ID and 20" - 30" OD is 2" greater than ID.

    About the Author

    Collin Champagne

    Approaching his 10-year work anniversary, Collin is one of our National Fireplace Institute (NFI) certified technicians and content manager for the eFireplacestore, eCanopy, and EliteDeals brands. He is a Master Hearth Professional, which means he is certified in all three hearth appliance fields—wood, gas and pellet.

    When not at work, he spends time with his wife, Lindsey, and his sons, Samuel and Eli, on their ranch enjoying their many animals. Completing projects around the ranch and spending quality time with his family are among his greatest joys. 

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    Questions About This Article

    All customer questions are answered by our NFI Certified Specialists free of charge!
    1 Question & 1 Answer
    from Ohio asked:
    July 2, 2019
    Why can a direct vent system vent horizontally and terminate with a cap on the outside of the wall and a B-vent system must terminate vertically above the roof line?
    1 Answer
    This is due to the way the fireplaces are engineered.  A direct vent model is sealed from the room with a solid glass panel and uses only outside air for combustion whereas a B-Vent gas fireplace is open with no solid glass front and uses primarily room air for combustion.  For more details, please see our <a href="">Gas Fireplace and Stove Buying Guide</a>.
    Submitted by: Tyler M. - NFI Master Hearth Professional on July 2, 2019

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