reaming, and be installed in a manner to permit free expansion and
contraction without damage to joints or hangers. Filings, dust, or dirt
shall be wiped from interior of pipe before connections are made.
3.1.5.1
Directional Changes
Changes in direction shall be made with fittings, except that bending of
pipe 100 mm 4 inches and smaller will be permitted, provided a pipe bender
is used and wide-sweep bends are formed. The centerline radius of bends
shall not be less than 6 diameters of the pipe. Bent pipe showing kinks,
wrinkles, or other malformations will not be accepted.
3.1.5.2
Functional Requirements
Piping shall be sloped 13 mm/3 m 1/2 inch/10 feet of pipe in the direction
of flow to ensure adequate oil drainage. Open ends of refrigerant lines or
equipment shall be properly capped or plugged during installation to keep
moisture, dirt, or other foreign material out of the system. Piping shall
remain capped until installation. Equipment piping shall be in accordance
with the equipment manufacturer's recommendations and the contract drawings.
3.1.5.3
Brazed Joints
Brazing shall be performed in accordance with AWS BRH, except as modified
herein. During brazing, the pipe and fittings shall be filled with a
pressure regulated inert gas, such as nitrogen, to prevent the formation of
scale. Before brazing copper joints, both the outside of the tube and the
inside of the fitting shall be cleaned with a wire fitting brush until the
entire joint surface is bright and clean. Brazing flux shall not be used.
Surplus brazing material shall be removed at all joints. Steel tubing
joints shall be made in accordance with the manufacturer's recommendations.
Tubing shall be protected against oxidation during brazing by continuous
purging of the inside of the piping using nitrogen. Piping shall be
supported prior to brazing and shall not be sprung or forced.
3.1.5.4
Threaded Joints
Threaded joints shall be made with tapered threads and made tight with PTFE
tape complying with ASTM D 3308 or equivalent thread-joint compound applied
to the male threads only. Not more than three threads shall show after the
joint is made.
3.1.5.5
Welded Joints
Welded joints in steel refrigerant piping shall be fusion welded. Changes
in direction of piping shall be made with welded fittings only; mitering or
notching pipe or other similar construction to form elbows or tees will not
be permitted. Branch connections shall be made with welding tees or forged
welding branch outlets. Steel pipe shall be thoroughly cleaned of all
scale and foreign matter before the piping is assembled. During welding,
the pipe and fittings shall be filled with a pressure regulated inert gas,
such as nitrogen, to prevent the formation of scale. Beveling, alignment,
heat treatment, and inspection of weld shall conform to ASME B31.1. Weld
defects shall be 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.
SECTION 15652A
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