3.1.2
Joints
Joints between sections of pipe and between pipe and fittings shall be
threaded, flanged, or welded as specified. Except as otherwise specified,
fittings 38 mm 1-1/2 inches and smaller shall be either threaded or socket
welded, and fittings 50 mm 2 inches and larger shall be either flanged or
butt welded. Pipe and fittings 32 mm 1-1/4 inches and larger installed in
inaccessible conduits or trenches under concrete floor slabs shall be
welded. Unless otherwise specified or indicated, connections to equipment
shall be made with black malleable iron unions for pipe 38 mm 1-1/2 inches
or smaller in diameter, and with flanges for pipe 50 mm 2 inches or larger
in diameter.
3.1.2.1
Threaded Joints
Threaded joints shall be made with tapered threads properly cut, and shall
be made tight with PTFE tape, or equivalent joint compound material applied
to the male threads only. Joint compound shall not be applied to fittings.
3.1.2.2
Welded Joints
a.
Welded joints shall be made as specified. Changes in direction of
piping shall be made with welding fittings only.
b.
Branch connection may be made with either welding tees or branch
outlet fittings. Branch outlet fittings shall be forged, flared
for improvement of flow where attached to the run, and reinforced
against external strains.
c.
Beveling, alignment, heat treatment, and inspection of weld shall
conform to ASME B31.1.
d.
Weld defects shall be removed and repairs made to the weld, or
weld joints shall be entirely removed and rewelded.
e.
Electrodes shall be stored and dried in accordance with AWS
D1.1/D1.1M or as recommended by manufacturer. Electrodes that
have been wetted or that have lost any of their coating shall not
be used.
3.1.2.3
Expansion Joints
Guiding of piping on both sides of expansion joint shall be in accordance
with published recommendations of manufacturer.
3.1.2.4
Flanges and Unions
Flanges shall be faced true, provided with metallic spiral wound
nonasbestos gaskets, and made square and tight. Union or flange joints
shall be provided in each line immediately preceding the connection to each
piece of equipment or material requiring maintenance such as coils, pumps,
control valves, and other similar items.
3.1.3
Supports
3.1.3.1
General
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NOTE: Mechanical and electrical layout drawings and
SECTION 15561A
Page 94
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