hangers. Filings, dust, or dirt shall be wiped from interior of the pipe
or tubing before connections are made. Changes in direction shall be made
with fittings, except that bending of pipe up to 100 mm 4 inches size will
be permitted, provided a pipe bender is used and wide sweep bends are
formed. The center line radius of bends shall not be less than six
diameters of the pipe. Bent pipe showing kinks, wrinkles, flattenings, or
other malformations will not be accepted. Vent pipes shall be installed
through the roof as directed and shall be flashed as specified. Horizontal
supply mains shall pitch up or down in the direction of flow as indicated.
The grade shall be not less than 25 mm in 12 m 1 inch in 40 feet. Reducing
fittings shall be used for changes in pipe sizes. Open ends of pipelines
and equipment shall be capped or plugged during installation to keep dirt
or other foreign materials out of the systems. Pipe not otherwise
specified shall be uncoated. Unions for copper pipe or tubing shall be
brass or bronze. Connections between ferrous piping and copper piping shall
be electrically isolated from each other with dielectric waterways.
3.1.1.1
Threaded Joints
Threaded joints shall be made with tapered threads properly cut, and shall
be made tight with polytetrafluoroethylene (PTFE) tape complying with ASTM
D 3308, or equivalent joint compound applied to the male threads only, and
in no case to the fittings.
3.1.1.2
Welded Joints
Welded joints shall be fusion-welded unless otherwise required. Changes in
direction of piping shall be made with welding fittings only. Branch
connection may be made with either welding tees or forged branch outlet
fittings. Branch outlet fittings shall be forged, flared for improvement
of flow where attached to the run, and reinforced against external strains.
Beveling, alignment, heat treatment, and inspection of weld shall conform
to ASME B31.1. Weld defects shall be removed and repairs made to the weld,
or the weld joints shall be entirely removed and rewelded at no additional
cost to the Government. Electrodes shall be stored and dried in accordance
with AWS D1.1/D1.1M or as recommended by the manufacturer. Electrodes that
have been wetted or that have lost any of their coating shall not be used.
3.1.1.3
Flanges and Unions
Flanges and unions shall be faced true, and made square and tight. Gaskets
shall be nonasbestos compressed material in accordance with ASME B16.21,
1.6 mm 1/16 inch thickness, full face or self-centering flat ring type.
The gaskets shall contain aramid fibers bonded with styrene butadiene
rubber (SBR) or nitrile butadiene rubber (NBR). NBR binder shall be used
for hydrocarbon service. 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.
3.1.1.4
Flared and Sweated Pipe and Tubing
Flared and sweated pipe and tubing shall be cut square and burrs shall be
removed. Both inside of fittings and outside of tubing shall be cleaned
with an abrasive before sweating. Care shall be taken to prevent annealing
of fittings and hard drawn tubing when making connection. Installation
shall be made in accordance with the manufacturer's recommendations.
Mitering of joints for elbows and notching of straight runs of pipe for
tees will not be permitted. Joints for soldered fittings shall be made
SECTION 15562A
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