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1. In addition, provide continuous flexible seals at door jamb edges for a fully weathertight <br /> installation. <br /> 2. Where door unit is power-operated, provide safety interlock switch to disengage power supply <br /> when pass door is open. <br /> 2.5 HARDWARE <br /> A. General: Provide heavy-duty,rust-resistant hardware,with galvanized or cadmium-plated <br /> or stainless steel fasteners,to suit type of door. <br /> B. Hinges: Provide heavy steel hinges at each end stile and at each intermediate stile,per <br /> manufacturer's recommendations for size of door. Attach hinges to door sections through stiles and rails with bolts <br /> and lock nuts or lock washers and nuts. Use rivets or self-ta.pping fasteners where access to nuts is not possible. <br /> Provide double-end hinges,where required,for doors exceeding 16 feet in width,unless otherwise recommended by <br /> door manufacturer. <br /> C. Rollers: Provide heavy-duty rollers,with steel ball bearings in case-hardened steel races, <br /> mounted with varying projections to suit slope of track. Extend roller shaft through both hinges where double hinges <br /> are required. Provide roller tires to suit size of track(3-inch diameter for 3-inch track;2-inch diameter for 2-inch <br /> track)and as follows: <br /> 1. Case-hardened steel tires for normal installations. <br /> D. Pull Handles,Locks and Latches: For manually operated doors,furnish lifting handles, <br /> locks,and locking device as follows: <br /> 1. Lifting Handles: Galvanized steel. <br /> 2. Locking Bars: Single side,operable from inside only. <br /> E. Fabricate locking device assembly with mortise lock,spring-loaded dead bolt, <br /> chromium-plated operating handle,cam plate,and adjustable locking bar to engage through slots in tracks. <br /> 1. Lock cylinder <br /> 2.6 COUNTERBALANCING MECHANISM <br /> A. Extension Spring: Operation by extension-spring counterbalance mechanism with <br /> aircraft-type steel cable over ball-bearing sheaves. Provide oil-tempered, wired springs with intemal safety rods. <br /> Combine operation with a spring bumper in each horizontal track to cushion door at end of opening operation. <br /> B. Torsion Spring: Operation by torsion-spring counterbalance mechanism,consisting of <br /> adjustable-tension,tempered-steel torsion springs mounted on a cross header tube or steel shaft. Connect to door with <br /> galvanized aircraft-type lift cables. Provide springs calibrated for 10,000 cycles minimum. <br /> C. Provide cast-aluminum or grey-iron casting cable drums,grooved to receive cable. Mount <br /> counterbalance mechanism with manufacturer's standard ball-bearing brackets at each end of shaft. Provide one <br /> additional midpoint bracket for shafts up to 16 feet long and two additional brackets at one-third points to support <br /> shafts over 16 feet long,unless closer spacing recommended by door manufacturer. <br /> D. Include a spring-loaded,steel or bronze cam mounted to bottom door roller assembly on each <br /> side,designed to automatically stop door if either cable breaks. <br /> E. Provide a spring bumper at each horizontal track to cushion door at end of opening operation. <br /> 2.7 MANUAL DOOR OPERATION <br /> A. Reduction-Drive Chain Hoist: Side-mounted unit consisting of an endless steel hand chain, <br /> chain pocket wheel with at least 3:1 reduction unit,roller chain-and-sprocket drive,end-mounted on counterbalance <br /> shaft. Operate with not more than 35 lb pull. <br /> 2.8 ELECTRIC DOOR OPERATORS <br /> Page 3 of 4 <br />