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DUCTWORK Section 15890 15-1207 Support ductwork in manner complying with SMACNA "HVAC Duct Construction Standards," latest edition, hangers and supports sections. Where special hanging of ductwork is detailed or shown on Drawings, Drawings shall be followed. a. Except where modified in individual paragraphs in this section or detailed on drawings, provide hanger support with minimum 18 gauge straps, 1 inch wide. Fold duct strap under bottom of duct. b. Install duct supports to rectangular ducts with sheet metal screws. Provide one screw through strap at top of duct and one screw through strap at bottom of duct. 2. Upper Connection of support to wood structure shall be with wood screws or lag screws in shear fastened in the upper one half of the wood structural member. Fasteners shall conform to the followina schedule: Duct Size Fastener Size/Type P/2 < 30" Two #10 x 1 '/2"wood screw 31 " < P/2 < 72" 1/4" x 1 '/2" lag screw P/2 > 73" 3/8" x 1 '/2" lag screw 3. Upper connection in tension shall not be used unless absolutely necessary. Where deemed necessary, the Contractor shall submit calculations to show the size fastener and penetration required to support loads in tension from wood in accordance with the followina schedule: E. Where ducts pass through interior partitions and exterior walls, conceal space between construction opening and duct or duct -plus- insulation with sheet metal flanges of same gauge as duct. Overlap opening on four sides by at least 1-1/2 inches. F. Where ductwork is exposed, Contractor to paint ductwork, supports, and air inlets and outlets to match adjacent architectural surfaces, or as directed by Architect. 3.02 INSTALLATION OF FABRIC DUCTWORK: A. Install fabric ductwork per manufacturer's written instructions. Manufacturer's written instruction shall be on site for IOR and/or Engineers review upon request. 3.03 INSTALLATION OF FLEXIBLE DUCTWORK A. Provide flexible ducts with supports at or near mid -length with 2 -inch wide, 26 -gauge steel hanger collar attached to the structure with an approved duct hanger. Installation shall minimize sharp radius turns or offsets. B. Make connections to rigid ductwork with Panduit style draw band. Provide one draw -band at inner liner and a second draw band over the outer vapor barrier material. 11 Duct Size Load per hanger P/2 < 30" 260 pounds per hanger 31" < P/2 < 72" 320 pounds per hanger 73" < P/2 <96" 460 pounds per hanger P/2 > 96" Not Allowed E. Where ducts pass through interior partitions and exterior walls, conceal space between construction opening and duct or duct -plus- insulation with sheet metal flanges of same gauge as duct. Overlap opening on four sides by at least 1-1/2 inches. F. Where ductwork is exposed, Contractor to paint ductwork, supports, and air inlets and outlets to match adjacent architectural surfaces, or as directed by Architect. 3.02 INSTALLATION OF FABRIC DUCTWORK: A. Install fabric ductwork per manufacturer's written instructions. Manufacturer's written instruction shall be on site for IOR and/or Engineers review upon request. 3.03 INSTALLATION OF FLEXIBLE DUCTWORK A. Provide flexible ducts with supports at or near mid -length with 2 -inch wide, 26 -gauge steel hanger collar attached to the structure with an approved duct hanger. Installation shall minimize sharp radius turns or offsets. B. Make connections to rigid ductwork with Panduit style draw band. Provide one draw -band at inner liner and a second draw band over the outer vapor barrier material. 11