2021-414-E-AMS-Riggs-Harrod Builders, Inc-SHSC Roof & HVAC Replacement

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Southern Human Services Center Smith Sinnett /2020072 HVAC and Roof Renovations Orange County,North Carolina HVAC Ducts and Casings 23 31 00 - 5 4.Butyl rubber gasket must be applied per the manufacturer’s instructions on all connections except for breakaway connections.Closed Cell Neoprene gasket must be applied per the manufacturer’s instructions on all breakaway connections.No substitution of connector system components or gaskets is permitted. 5.All duct installed using engineered connectors must adhere to the manufacturer’s published assembly and installation guidelines for all standard,breakaway,roof-top or specialty connections unless otherwise specified. B.Formed-on Flanges: 1.Lockformers TDC or Engles TDF may be used in accordance with T-25 flanges of SMACNA HVAC Duct Construction Standards,provided that corner pieces with bolts are used. If TDF/TDC flanges are damaged,replace the damaged joint(s)by straightening and reinforcing with minimum 1-1/2 x 1-1/2 x 1/4 angle at each side of transverse joint PART 3 EXECUTION 3.01 INSTALLATION A.Install,support,and seal ducts in accordance with SMACNA (DCS). B.During construction provide temporary closures of metal or taped polyethylene on open ductwork to prevent construction dust from entering ductwork system. C.Install ductwork parallel to building walls and ceilings and at such heights not to obstruct any portion of window,doorway,stairway,or passageway. Install ductwork to allow adequate access and service space for equipment and access clearances for cable tray/j-hooks.Refer to drawings and/or manufacturer's recommendations Install vertical ductwork plumb. Make allowances for beams,pipes or other obstructions in building construction and for work of other contractors. Check plans showing work of other trades and consult with Engineer in event of any interference. D.Where interferences develop in the field,offset or reroute ductwork as required to clear such interferences. Do not divide duct and do not route any other utilities such as piping or conduit through duct. In all cases,consult drawings for exact location of space allocated for duct,ceiling heights,door and window openings,or other architectural details before fabricating or installing duct. Consult Designer where conflicts arise between ductwork and other utilities which cannot be resolved by relocating duct. E.Where offsets in ductwork are required,contractor to use standard 30,45 or 90-degree elbows. Where space constraints do not allow for the use of standard elbows for offsets,use of angled offsets as depicted by SMACNA Figure 2-7 (Angled Offset Type 1)may be used with maximum angle of offset not to exceed 15 degrees maximum.Offsets Type 2 and 3 in SMACNA Figure 2-7 shall not be allowed. F.Rectangular Duct Elbows: 1.Rectangular Duct:Unless specific type is indicated,provide radius elbows with splitter vanes with minimum centerline radius to width or diameter ratio of 1.5 a.1.5 radius elbows with full spliter vanes as follows: 1)One vane for duct width 2-12" 2)Two vanes for duct width 13-20" 3)Three vanes for duct width 21"-36" 4)Four vanes for duct width 38"and larger 5)Fabricate vanes in accordance with SMACNA. b.Rectangular throad elbows with turning vanes where 1.5 radius elbows do not fit. c.Rectangular throat/radius heel elbows or rectangular elbows without turning vanes shall not be used. G.Round and Oval Duct Elbows: 1.Unless specific type is indicated,use radius elbows with centerline radius to diameter ratio of 1.5.ONLY where1.5 radius elbows do not fit,1.0 radius elbows may be used if approved by the Engineer. H.Construct ductwork so that interior surfaces are smooth. Internal duct hangers and internal bracing are not allowed. Refer to above for internal tie rods. DocuSign Envelope ID: 94E7997D-4F29-42F6-A9B4-0A160438D2A6