Furnish and install, at locations shown on plans, or in accordance with schedules, Low leakage dampers shall meet the following minimum construction standards: Frames shall be 5” x 1” x .125” (minimum thickness) (127 x 25 x 3.2) 6063-T6 extruded aluminum hat channel with hat mounting flanges on both sides of the frame. Each corner shall be reinforced with two die formed internal braces and machine staked for maximum rigidity. Blades shall be airfoil type extruded aluminum (maximum 6” (152) depth) with integral structural reinforcing tube running full length of each blade.
Blade edge seals shall be extruded double edge design with inflatable pocket which enables air pressure from either direction to assist in blade to blade seal off. Blades seals shall be mechanically locked in extruded blade slots, yet shall be easily replaceable in field. Adhesive or clip-on type blade seals are not acceptable. Bearings shall be non-corrosive molded synthetic. Axles shall be hexagonal (round not acceptable) to provide positive locking connection to blades and linkage. Linkage shall be concealed in frame. Submittal must include leakage, maximum air flow and maximum pressure ratings based on AMCA Publication 500. Damper shall be tested and licensed in accordance with AMCA 511 for Air Performance and Air Leakage.
Damper widths from 12” to 48” (305 to 1219) wide shall not leak any greater than 8 cfm sq.ft. @ 4” w.g. and a maximum of 3 CFM sq.ft. @ 1” w.g. (15.2 l/s-m2 at .25 kPa). Damper shall be factory equipped with fast acting 8-second spring return electric actuator with 40,000 open/closed cycle testing, and shall be in all respects equivalent to Ruskin Model CD50GS.