shall be at the discretion of the curtain wall manufacturer. Perform
fitting and assembling of components in the shop to the maximum extent
practicable. Anchorage devices shall permit adjustment in three
directions. Exposed fastenings used on finished surfaces shall be truss
head, flat head, or oval head screws or bolts.
3.1.1
Joints
Provide welded or mechanical fasteners as indicated or specified. Match
joints in exposed work to produce continuity of line and design. Bed-joints
or rabbets receiving calking or sealing material shall be minimum 20 mm 3/4
inch deep and 10 mm 3/8 inch wide at mid ambient temperature range.
3.1.2
Welding
Conform to AWS D1.1/D1.1M. Use methods and electrodes recommended by
manufacturers of base metal alloys. Welding rods shall be of an alloy that
matches the color of the metal being welded. Protect glass and other
finish from exposure to welding spatter. Ground and finish weld beads on
exposed metal surfaces to minimize mismatch and to blend with finish on
adjacent parent metal. If flux is used in welding aluminum, completely
remove it immediately upon completion of welding operations. Do not use
exposed welds on aluminum surfaces.
3.1.3
Soldering and Brazing
Provide as recommended by suppliers.
Solder only for filling or sealing
joints.
3.1.4
Ventilation and Drainage
Provide internal ventilation drainage system of weeps or based on
principles of pressure equalization to ventilate the wall internally and to
discharge condensation and water leakage to exterior as inconspicuously as
possible. Flashings and other materials used internally shall be
nonstaining, noncorrosive, and nonbleeding.
3.1.5
Protection and Treatment of Metals
3.1.5.1
General
Remove from metal surfaces lubricants used in fabrication and clean off
other extraneous material before leaving the shop.
3.1.5.2
Galvanic Action
Provide protection against galvanic action wherever dissimilar metals are
in contact, except in the case of aluminum in permanent contact with
galvanized steel, zinc, stainless steel, or relatively small areas of white
bronze. Paint contact surfaces with one coat bituminous paint or apply
appropriate calking material or nonabsorptive, noncorrosive, and
nonstaining tape or gasket between contact surfaces.
3.1.5.3
Protection for Aluminum
Protect aluminum which is placed in contact with, built into, or which will
receive drainage from masonry, lime mortar, concrete, or plaster with one
coat of alkali-resistant bituminous paint. Where aluminum is contacted by
absorptive materials subject to repeated wetting or treated with
SECTION 08900
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