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OC Sportsplex Pool HVAC Unit Replacement <br />PDC Project 23022 HVAC Ducts and Casings 23 31 00 - 3 <br />B.Where the size for a duct segment is not indicated,the duct segment size shall be equal to the <br />largest duct segment to which it is connected.Transition to smaller size shall occur on the side of <br />the fitting where smaller size is indicated. <br />C.No variation of duct configuration or size permitted except by written permission. Size round duct <br />installed in place of rectangular ducts in accordance with ASHRAE (FUND)Handbook - <br />Fundamentals. <br />D.Construct T's,bends,and elbows with radius of not less than 1-1/2 times width of duct on <br />centerline. Where not possible and where rectangular elbows must be used,provide air foil <br />turning vanes of perforated metal with glass fiber insulation. <br />E.Increase duct sizes gradually,not exceeding 15 degrees divergence wherever possible;maximum <br />30 degrees divergence upstream of equipment and 45 degrees convergence downstream. <br />F.Fabricate continuously welded round and oval duct fittings in accordance with SMACNA (DCS). <br />G.Where ducts are connected to exterior wall louvers and duct outlet is smaller than louver frame, <br />provide blank-out panels sealing louver area around duct. Use same material as duct,painted <br />black on exterior side;seal to louver frame and duct. <br />2.04 HANGERS AND SUPPORTS <br />A.Refer to the Structural Drawngs and Details for the limitations and applications of each type of <br />hanger and weight when attaching to bar joists,trusses,or other building Structural elements.The <br />Contractor shall be responsible for providing additional miscellaenous steel,unistrut,and other <br />components to span multiple joists as required by the Structural Drawings to distribute <br />concentrated loads. <br />B.Unless otherwise indicated,use straps or Z bar hangers with 3/8”rods to support rectangular ducts <br />48”wide and smaller and trapeze hangers with rods or angles to support rectangular ducts over <br />48”wide. <br />1.Use trapeze hangers to support externally insulated ductwork with weight bearing inserts. <br />C.For round ducts 24"diameter or smaller,use single hanger. <br />1.Cable Suspension System may be used up to 16"diameter <br />2.Round Duct Strap Bracket by Ductmate Industries may be used up to 24"diameter. <br />D.For round ducts over 24"diameter,use 2 hangers with half round trapeze. <br />E.For round ducts over 25”diameter or larger,use 2 minimum 3/8”rods with trapeze. <br />F.The following upper attachments,upper attachment devices,lower hanger attachments,hanger <br />devices,and/or hanger attachments are not allowed except where specifically indicated: <br />1.Hook or loop. <br />2.Nailed pin fasteners. <br />3.Expansion nails without washers. <br />4.Powder charged or mechanically driven fasteners (forced entry anchors). <br />5.Beam or "C"clamps without retaining clips or friction clamps (provide retaining clips <br />6.for "C"clamps). <br />7.Friction clamps for ductwork over 12". <br />8.Non-factory manufactured upper attachments for metal pan deck including wire coil and <br />double circle (Items 16 and 17 of Fig 4-3 of SMACNA HVAC Duct Construction Standards <br />95). <br />9.Wire hanger. <br />10.Trapeze hangers supported by wires or straps. <br />11.Rods,straps or welded studs directly attached to metal deck. <br />12.Drilled hole with attachment to structural steel. <br />13.Lag screw expansion anchor. <br />14.Rivets. <br />G.Supporting devices shall be standard products of manufacturers having published load ratings. <br />Docusign Envelope ID: D4F3B98E-0756-4A0C-A3AD-05AA32D39F1C