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Southern Human Services Center Smith Sinnett /2020072 <br />HVAC and Roof Renovations Orange County,North Carolina <br />HVAC Ducts and Casings 23 31 00 - 2 <br />G.Return and Relief: -2 inch w.g.pressure class,galvanized steel. <br />H.General Exhaust: -2 inch w.g.pressure class,galvanized steel. <br />I.Outside Air Intake: -2 inch w.g.pressure class,galvanized steel. <br />J.Transfer Air and Sound Boots: 1 inch w.g.pressure class. <br />2.02 MATERIALS <br />A.Galvanized Steel for Ducts: Hot-dipped galvanized steel sheet,ASTM A653/A653M FS Type B, <br />with G90/Z275 coating. <br />B.Joint Sealers and Sealants: Non-hardening,water resistant,mildew and mold resistant. <br />1.Manufacturers: <br />a.Childers <br />b.Ductmate <br />c.Durodyne <br />d.Foster <br />e.Hardcast <br />f.McGill Airseal <br />g.Sheet Metal Connectors,Inc. <br />h.Or Approved Equal <br />2.Flexible,water-based,adhesive sealant designed for use in all pressure duct systems. After <br />curing,it shall be resistant to ultraviolet light and shall prevent the entry of water,air,and <br />moisture into the duct system. Sealer shall be UL 723 and UL 181B-M listed and meet NFPA <br />requirements for Class 1 ductwork.VOC shall be <75 g/l. <br />3.Neoprene gasket must be closed cell rubber based sealing tape and must pass UL 94 HF-1. <br />4.Butyl rubber gasket which complies with UL 723,Mil-C 18969B and TTS-S-001657.This <br />material,in addition to the above,shall not contain vegetable oils,fish oils,or any other type <br />vehicle that will support fungal and/or bacterial growth. <br />5.Surface Burning Characteristics: Flame spread index of zero and smoke developed index of <br />zero,when tested in accordance with ASTM E84. <br />6.For Use With Flexible Ducts: UL labeled. <br />C.Hanger Rod: ASTM A36/A36M;steel,galvanized;threaded both ends,threaded one end,or <br />continuously threaded. <br />D.Cable Suspension System: <br />1.Suspension system shall be Gripple Hang-Fast as manufactured and supplied by Gripple, <br />Inc.,or Ductmate "Clutcher"cable hanging system. <br />2.Suspension system shall be load rated and verified by SMACNA Testing and Research <br />Institute to be in compliance with SMACNA Standards. <br />3.All suspension systems shall used galvanized hardware. <br />2.03 DUCTWORK FABRICATION <br />A.Fabricate and support in accordance with SMACNA (DCS)HVAC Duct Construction Standards, <br />Metal and Flexible,3rd edition,2005,except as modified below <br />1.Internal tie rods or bracing are not allowed for ductwork 36"and below.Tie rods shall be 1/2", <br />3/4",1",1-1/4"or 1-1/2"galvanized rods with bolt assembly consisting of rubber washer and <br />friction anchored threaded insert similar to Ductmate Easyrod or PPI Condu-Lock. <br />2.Internal tie rods are not allowed for ductwork in chase and other non-accessible locations. <br />B.For round ducts operating above +10"w.g.or below -10"w.g.,follow SMACNA Round Industrial <br />Duct Construction Standard,3rd edition.ANSI/SMACNA 005-2013. <br />C.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 />D.Provide duct material,gages,reinforcing,and sealing for operating pressures indicated. <br />E.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 />DocuSign Envelope ID: 94E7997D-4F29-42F6-A9B4-0A160438D2A6