UL 1777

Standard for Chimney Liners

ANSI & Non-ANSI Categorized appliances or per appliance’s installation instructions.


304/444 Stainless Steel Inner wall

Plan Specification:

  • All portions of the vent system shall be double-wall gas vent, tested and listed to UL777 ‘Standard for Chimney Liners’. The vent system shall have a materials or equipment acceptance number.
  • All portions of the vent system shall be supplied, including appliance adapters, straight lengths, adjustable lengths, elbows, drain sections, test ports, reducers, boot tees, tee caps, support plates, storm collar, flashing and chimney top.
  • The vent system shall be installed per the vent manufacturer’s recommendations and in conformance with the manufacturer’s 15 year 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


(800) 218-1990

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.

Boilers Have Changed, Shouldn’t Your Combustion Air System?

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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Sat-Sun: Closed


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(800) 218-1990