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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 - 6 <br />I.Support coils,filters,air terminals,dampers,sound attenuating devices,or other devices installed <br />in duct systems with angles or channels and make all connections to such equipment including <br />equipment furnished by others. Secure frames with gaskets,nuts,bolts and washers. <br />J.Flexible ducts shall not exceed 5 feet in length.Bends,kinks,and sagging of flexible duct will not <br />be accepted.The maximum permitted sag is 1/2"per foot of support spacing. <br />K.Install outside air intake duct to pitch down at minimum 1”per 20 ft toward intake louver or plenum <br />and to drain to outside of building. Solder or seal seams to form watertight joints. <br />L.Where 2 different metal ducts meet,install joint in such a manner that metal ducts do not contact <br />each other by using proper gasket seal or compound. <br />M.Flexible Ducts: Connect to metal ducts with adhesive plus sheet metal screws. <br />1.Flexible ducts are not allowed for special exhaust systems,such as laboratory exhaust, <br />vehicle exhaust,etc. <br />2.Splicing of flexible duct will not be allowed. <br />3.Flexible ducts shall not pass through any partition,wall,floor,or ceiling. <br />N.Duct sizes indicated are inside clear dimensions. For lined ducts,maintain sizes inside lining. <br />O.Provide openings in ductwork where required to accommodate thermometers and controllers. <br /> Provide pilot tube openings where required for testing of systems,complete with metal can with <br />spring device or screw to ensure against air leakage. Where openings are provided in insulated <br />ductwork,install insulation material inside a metal ring. <br />P.Locate ducts with sufficient space around equipment to allow normal operating and maintenance <br />activities. <br />Q.Use double nuts and lock washers on threaded rod supports. <br />R.At exterior wall louvers,seal duct to louver frame and install blank-out panels. <br />S.All trapeze hanger rods shall be cut to within 1"of the bottom nut. <br />END OF SECTION <br />DocuSign Envelope ID: 94E7997D-4F29-42F6-A9B4-0A160438D2A6