Furnish and install at locations shown on plans or in accordance with schedules, low leakage dampers that meet the following minimum construction standards:
| Specification | Description |
|---|---|
| VD-1240 Damper Frame | 4 in. (102 mm) x 1 in. (25 mm) x 6063T5 extruded aluminum channel with .081 in. (2.1 mm) minimum wall thickness. Optional mounting flanges on both sides of frame. |
| VD-1241 Damper Frame | 8-1/8 in. (206 mm) x 1 in. (25 mm) x 6063T5 extruded aluminum channel with .081 in. (2.1 mm) minimum wall thickness. Optional mounting flanges on both sides of frame. Thermal gasket between frame sections. |
| Damper Corner | Reinforced with two die formed internal braces and machine staked for maximum rigidity |
| Damper Blades | 4 in. (102 mm) wide, airfoil type extruded aluminum, with integral structural reinforcing tube running full length of each blade |
| Axles | 1/2 in. (13 mm) plated steel hex |
| Bearings | Non-corrosive molded synthetic. Hexagonal axles to provide positive locking connection to blades and linkage (round axles are not acceptable). |
| Linkage | Concealed in end channel of frame |
| Blade Seals | Extruded double edge design with inflatable pocket, allowing air pressure from either direction to assist in blade-to-blade seal off. Blade seals mechanically locked in extruded blade slots, and easily replaceable in field. Adhesive or clip-on type blade seals are not acceptable. |
| Control Shaft | 6 x 1/2 in. (152 x 13 mm) diameter. Outboard support bearing supplied with all single section dampers for field-mounted actuators. Factory-installed jackshaft supplied with all multiple section dampers. |
| Finish | Mill |