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PART-3 EXECUTION • <br /> 3.1. INSTALLATION, APPLICATION, ERECTION <br /> A. Support ductwork on each side of the duct with suitable sheared <br /> strips of galvanized metal or 1" x 1/8" galvanized steel band iron <br /> hangers. <br /> B. Attach hangers to the duct work using sheet metal screws. <br /> C. Secure hangers to concrete structure with approved anchor shields <br /> and to steel structure by means of C-clamps. <br /> D. Space hangers approximately eight feet along the duct except as <br /> noted below. <br /> E. For ducts 60" and larger and heavy sections, such as welded duct <br /> and sound absorbers, space hangers at approximately four foo�t <br /> intervals. <br /> F. Obstructions shall not be located within ducts. <br /> G. Do not exceed 45 degrees for easement transition angle. • <br /> H. Seal all transverse joints with approved sealer in accordance with <br /> manufacturer's directions. Also seallongitudinal joints which <br /> prove to leak. <br /> I. Insulation: Where drawings and insulating specifications indicate <br /> that ducts are to be insulated make provisions for neat insulation <br /> finish around damper operating quadrants, splitter adjusting <br /> clamps, access doors, and similar operating devices. Metal collar <br /> equivalent in depth to insulation thickness and of suitable size to <br /> which insulation may be finished to be mounted on duct. <br /> J. Counterflashing: Counterflash all ducts where they pierce the roof. <br /> K. Pitot Ports: Pitot ports for measuring airflow to be located in ea�h <br /> main duct at the downstream end of the straightest run of the main <br /> and before the first branch take-off. Pitot ports to be formed by <br /> drilling 7/16" holes in the duct, lined up perpendicular to airfloti�- <br /> on maximum 8" centers and at least three to a duct, evenly spaced. <br /> Holes to be plugged with plastic plugs. Provide access to these for • <br /> future rebalancing. <br /> ICT 99184 <br /> 15890 - 6 <br />