routed through an accessible trench system (i.e.
concrete, fiberglass, PVC, etc). The designer will
specifically detail the trench design as well as
fully detail the piping techniques necessary to
accommodate oil circulation at both full and part
load conditions. Oil circulation is extremely
critical to the successful operation of any
refrigerant system. Designers will avoid creating
any oil traps within a refrigerant piping system.
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Pipe and fitting installation shall conform to the requirements of ASME
B31.1. Pipe shall be cut accurately to measurements established at the
jobsite, and worked into place without springing or forcing, completely
clearing all windows, doors, and other openings. Cutting or other
weakening of the building structure to facilitate piping installation will
not be permitted without written approval. Pipe or tubing shall be cut
square, shall have burrs removed by reaming, and shall permit free
expansion and contraction without causing damage to the building structure,
pipe, joints, or hangers.
3.1.1
Directional Changes
Changes in direction shall be made with fittings, except that bending of
pipe 100 mm (4 inches) 4 inches and smaller will be permitted, provided a
pipe bender is used and wide weep bends are formed. Mitering or notching
pipe or other similar construction to form elbows or tees will not be
permitted. The centerline radius of bends shall not be less than 6
diameters of the pipe. Bent pipe showing kinks, wrinkles, flattening, or
other malformations will not be accepted.
3.1.2
Functional Requirements
Piping shall be installed 4 mm per m 1/2 inch per 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. Equipment and piping arrangements shall fit
into space allotted and allow adequate acceptable clearances for
installation, replacement, entry, servicing, and maintenance.
3.1.3
Fittings and End Connections
3.1.3.1
Threaded Connections
Threaded connections 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.
3.1.3.2
Brazed Connections
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
SECTION 15182
Page 18
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