3.2.4
Protection From Insulation Materials
Equipment and structures shall be adequately protected from damage from
insulation materials. After completion of the work, equipment and
structures shall be cleaned, repaired, and restored to their original
state. Casings which become corroded, discolored, or otherwise damaged
shall be repaired by replacement of casing or other means acceptable to the
Contracting Officer.
3.3
CASING INSTALLATION
3.3.1
Structural Steel Grid System
Casing shall be installed on aluminized structural steel grid system of
subgirts designed, furnished, and installed by the Contractor. The
subgirts shall be of sufficient size, gage, and depth to provide adequate
support and a smooth exterior surface and shall be welded to the equipment
and structural support surfaces. Subgirts shall be of sufficient depth to
provide for application of the full thickness of insulation over the
stiffeners, access doors, flanges, ribs, and other surfaces having uneven
contours to provide a smooth finished surface. Subgirts on vertical and
bottom surfaces shall be at a maximum spacing of 1220 mm four feeton
centers. Subgirts on roof surfaces shall be at a maximum spacing of 600 mm
two feet on centers. The walking surfaces shall be such as to transmit an
external 114 kg 250 pound walking load from the casing to the structural
steel grid system without compression of the insulation material.
3.3.2
Access Openings
Access doors and other penetrations through the insulation shall have
insulation fitted closely to the fittings and shall be neatly framed and
flashed to make weathertight and to create a pleasing appearance. Hinged
or lift-off doors designed for convenient opening or removal shall be
provided with nameplates, code stampings, and nonprojecting connections at
all access openings. Access openings shall be pitched for water runoff and
have flashing at door head as shown in SMACNA Arch. Manual.
3.3.3
Weatherproofing
Install casing with proper overlap to make the installation weathertight.
The casing shall be carefully fabricated and fitted to ensure a neat
appearance. Provide closures, flashings, and seals. The open ends of
fluted sections shall be provided with tightfitting closure pieces.
Flashing shall be suitably formed and installed so that water cannot enter
and wet the insulation. The flashing shall be designed and installed to
readily drain any water that might enter. Joints or openings in casing
which cannot be effectively sealed from entry of moisture by flashings or
laps shall be weatherproofed by application of an aluminum-pigmented sealer
manufactured for this type of service.
3.3.4
Convection Stops
Furnish and install convection stops on vertical surfaces over 3.70 meters
12 feet tall. The maximum interval between convection stops shall be 3.70
meters 12 feet. The convection stops shall consist of steel channels or Z
girts.
SECTION 15864N
Page 108
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