UL 1978

Standard for Grease Duct

UL 2221

Standard for Tests of Fire Resistive Grease Duct Enclosure Assemblies

For kitchen hoods


304/316/441 Stainless Steel Inner wall, 1” air insulation or 1″, 2″ or 3″ fiber insulation, aluminized/304/316 steel outer wall

Plan Specification:

  • All portions of the vent system shall be double-wall gas vent, tested and listed to UL1978 ‘Standard for Grease Duct’ & UL2221 ‘Standard for Tests of Fire Resistive Grease Duct Enclosure Assemblies’. The grease duct system shall have a materials or equipment acceptance number.
  • All portions of the vent system shall be supplied, including square to round to transitions, straight lengths, adjustable lengths, elbows, access doors, reducers, grease tees, tee caps, support plates and fan adapters.
  • 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

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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Contact Info

Our Office

100 S. Sylvania Ave
Fort Worth, TX, 76111

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Sat-Sun: Closed


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(800) 218-1990