UL 441

Type B Gas Vent

For Listed ANSI Category I Appliances, Draft Hood‐Equipped Appliances, or Appliances Listed for use with Type B Gas Vent and Insulated supply air duct. Max.


Made of Alum or SS inner, .5” or 1” air space and low cost outer steel jacket. Operating Temp of 480 deg and Must be under a Negative Pressure at all times.

Plan Specification:

  • All portions of the vent system shall be double‐wall Type B gas vent, tested and listed to UL441 ‘Standard for Gas Vents.’ The vent system shall be supplied by Texas Draft 817‐841‐8303.
  • All portions of the vent system shall include draft hood connectors, straight lengths, adjustable lengths, elbows, reducers, tees, tee caps, barometric dampers, support plates, storm collar, flashing and chimney top.
  • The vent system shall be configured and installed per the appliance and vent manufacturer’s recommendations and in conformance with the manufacturer’s warranty.
  • Submit vent drawings with draft calculation report and they shall be based upon the latest edition of NFPA 54 tables or ASHRAE’s Chimney Design Equation and submitted with the appliance manufacturers’ requirements for review and approval by the engineer.
  • Draft calculations non‐compliance with NFPA 54 or insufficient draft shall have a mechanical draft system installed. Contact Texas Draft at 817‐841‐8303 for the proper selection of the mechanical draft system.

Save time and money with our stock of B-vent, special gas vent, polypropylene, pressure stack, barometric dampers, aztech flashing, and pizza oven fans. Get your system layout today with a Texas Draft Stamp of Approval.

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Pressure Air Systems from US Draft Co only provides the air needed for the
mechanical room, saving energy! Contact us to size your system.

Call: (800) 218-1990

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100 S. Sylvania Ave
Fort Worth, TX, 76111

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(800) 218-1990