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DocuSign Envelope ID: 9826C043- 4C32- 49CD- A4CC- DC28ABAB7CE7 <br />SECTION 239000 - METAL DUCTS <br />H. Install ducts close to walls, overhead construction, columns, and other structural and permanent <br />enclosure elements of building. <br />I. Install ducts with a clearance of 1 inch, plus allowance for insulation thickness. <br />J. Route ducts to avoid passing through transformer vaults and electrical equipment rooms and <br />enclosures. <br />K. Where ducts pass through non - fire -rated interior partitions and exterior walls and are exposed to <br />view, cover the opening between the partition and duct or duct insulation with sheet metal flanges of <br />same metal thickness as the duct. Overlap openings on four sides by at least 1 -1/2 inches. <br />L. Where ducts pass through fire -rated interior partitions and exterior walls, install fire dampers. <br />Comply with requirements in Division 23 Section "Air Duct Accessories" for fire and smoke dampers. <br />M. Protect duct interiors from moisture, construction debris and dust, and other foreign <br />materials. Comply with SMACNA's "Duct Cleanliness for New Construction Guidelines." All <br />ductwork open ends to be capped during the course of construction. <br />N. Owner and / or owner's representative shall be notified a minimum of 24 hours in advance of <br />any duct pressure testing. Results of duct pressure testing shall be forwarded to the owner / <br />engineer for approval and included in the final test and balance report. All ductwork shall be <br />pressure tested per recommendations in SMACNA. <br />10.2 ADDITIONAL INSTALLATION REQUIREMENTS FOR COMMERCIAL KITCHEN HOOD EXHAUST <br />DUCT <br />A. Install commercial kitchen hood exhaust ducts without dips and traps that may hold grease, and <br />sloped a minimum of 2 percent to drain grease back to the hood. <br />B. Install fire -rated access panel assemblies at each change in direction and at maximum intervals of as <br />allowed by NC Building Code in horizontal ducts, and at every floor for vertical ducts, or as indicated <br />on Drawings. Locate access panel on top or sides of duct a minimum of 1 -1/2 inches from bottom of <br />duct. <br />C. Do not penetrate fire -rated assemblies except as allowed by applicable building codes and <br />authorities having jurisdiction. <br />11.2 SEAM AND JOINT SEALING <br />A. Seal duct seams and joints for duct static - pressure and leakage classes specified in "Performance <br />Requirements" Article, according to SMACNA's "HVAC Duct Construction Standards - Metal and <br />Flexible," Table 1 -2, "Standard Duct Sealing Requirements," unless otherwise indicated. <br />B. Seal Classes: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," <br />Table 1 -2, "Standard Duct Sealing Requirements." <br />12.2 HANGER AND SUPPORT INSTALLATION <br />A. Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Chapter 4, <br />"Hangers and Supports." <br />A. Building Attachments: Concrete inserts, powder- actuated fasteners, or structural -steel fasteners <br />appropriate for construction materials to which hangers are being attached. <br />1. Where practical, install concrete inserts before placing concrete. <br />2. Install powder- actuated concrete fasteners after concrete is placed and completely cured. <br />3. Use powder- actuated concrete fasteners for standard - weight aggregate concretes or for slabs <br />more than 4 inches thick. <br />4. Do not use powder- actuated concrete fasteners for lightweight- aggregate concretes or for <br />slabs less than 4 inches thick. <br />1. Do not use powder- actuated concrete fasteners for seismic restraints. <br />B. Hanger Spacing: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and <br />Flexible," Table 4 -1, "Rectangular Duct Hangers Minimum Size," and Table 4 -2, "Minimum Hanger <br />Sizes for Round Duct," for maximum hanger spacing; install hangers and supports within 24 inches <br />of each elbow and within 48 inches of each branch intersection. <br />C. Hangers Exposed to View: Threaded rod and angle or channel supports. <br />D. Support vertical ducts with steel angles or channel secured to the sides of the duct with welds, bolts, <br />sheet metal screws, or blind rivets; support at each floor and at a maximum intervals of 16 feet. <br />E. Install upper attachments to structures. Select and size upper attachments with pull -out, tension, and <br />shear capacities appropriate for supported loads and building materials where used. <br />14.2 SEISMIC - RESTRAINT - DEVICE INSTALLATION <br />A. Install ducts with hangers and braces designed to support the duct and to restrain against seismic <br />forces required by applicable building codes. Comply with SMACNA's "Seismic Restraint Manual: <br />Guidelines for Mechanical Systems" and requirements of Delegated Design in Division 23 Section <br />"Vibration and Seismic Controls for HVAC." <br />15.1 CONNECTIONS <br />A. Make connections to equipment with flexible connectors complying with Division 23 Section "Air Duct <br />Accessories." <br />B. Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible" for branch, outlet <br />and inlet, and terminal unit connections. <br />Reece, Noland & McElrath, Inc. 239000-4 Orange County Board of Elections <br />Orange Co., NC 05/04/18 <br />