H-4 "Aluminum Louver :
1. Louver frames shall be fabricated from 1.22 mm (18 gage), extruded aluminum sheet of 1.22mm(18 gage) thickness. Louvers shall have blades of the overlapping type providing maximum weather tightness while allowing free air flow.
2. Provide flanges on interior face of frames where air intake or exhaust louvers are indicated to be connected with mechanically operated dampers or metal ductwork.
3. Provide aluminum insect/bird screens in rewirable frames on exterior face of louvers. Grid dimensions of insect/ bird screen mesh will be 12 mm square."