1. All window members, including muntin bars and glazing beads shall be extruded aluminum alloy 638-15, not less than 1 inch deep, 5/32" thick and weighing not less than .461 pounds per linear foot. e. Fasteners: Screws, nuts, washers, bolts, and rivets and other miscellaneous fastening devices incorporated in the windows shall be of aluminum. All anchoring de- vices in the erection of the windows shall be of aluminum. Steel anchors may be used provided that they be properly isolated from the aluminum, ce. Erection: Aluminum windows shall be erected in a secure and workmanlike manner to assure weathertight construction and a permanent watertight joint shall be made at the junction of the sill and side frame members. welding flux is used, it shall be completely removed immediately upon completion of the welding operation. 9-5 Where