manufacturer's recommendations. Mitering of joints for elbows and notching
of straight runs of pipe for tees will not be permitted. Joints shall be
made up with fittings of compatible material and made for the specific
purpose intended.
3.7.1
Threaded
Threaded joints shall have American Standard taper pipe threads conforming
to ASME B1.20.1. Only male pipe threads shall be coated with graphite or
with an approved graphite compound, or with an inert filler and oil, or
shall have a polytetrafluoroethylene tape applied.
3.7.2
Mechanical Couplings
Mechanical couplings may be used in conjunction with grooved pipe for
aboveground, ferrous or non-ferrous, domestic hot and cold water systems,
in lieu of unions, brazed, soldered, welded, flanged, or threaded joints.
Mechanical couplings are permitted in accessible locations including behind
access plates. Flexible grooved joints will not be permitted, except as
vibration isolators adjacent to mechanical equipment. Rigid grooved joints
shall incorporate an angle bolt pad design which maintains metal-to-metal
contact with equal amount of pad offset of housings upon installation to
ensure positive rigid clamping of the pipe. Designs which can only clamp
on the bottom of the groove or which utilize gripping teeth or jaws, or
which use misaligned housing bolt holes, or which require a torque wrench
or torque specifications will not be permitted. Rigid grooved pipe
couplings shall be for use with grooved end pipes, fittings, valves and
strainers. Rigid couplings shall be designed for not less than 862 kPa 125
psi service and appropriate for static head plus the pumping head, and
shall provide a watertight joint. Grooved fittings and couplings, and
grooving tools shall be provided from the same manufacturer. Segmentally
welded elbows shall not be used. Grooves shall be prepared in accordance
with the coupling manufacturer's latest published standards. Grooving
shall be performed by qualified grooving operators having demonstrated
proper grooving procedures in accordance with the tool manufacturer's
recommendations. The Contracting Officer shall be notified 24 hours in
advance of test to demonstrate operator's capability, and the test shall be
performed at the work site, if practical, or at a site agreed upon. The
operator shall demonstrate the ability to properly adjust the grooving
tool, groove the pipe, and to verify the groove dimensions in accordance
with the coupling manufacturer's specifications.
3.7.3
Unions and Flanges
Unions and flanges and mechanical couplings shall not be concealed in
walls, ceilings, or partitions. Unions shall be used on pipe sizes 65 mm
2-1/2 inches and smaller; flanges shall be used on pipe sizes 80 mm 3 inches
and larger.
3.7.4
Grooved Mechanical Joint
Grooves shall be prepared according to the coupling manufacturer's
instructions. Grooved fittings, couplings, and grooving tools shall be
products of the same manufacturer. Pipe and groove dimensions shall comply
with the tolerances specified by the coupling manufacturer. The diameter
of grooves made in the field shall be measured using a "go/no go" gauge,
vernier or dial caliper, narrow-land micrometer, or other method
specifically approved by the coupling manufacturer for the intended
application. Groove width and dimension of groove from end of pipe shall
SECTION 15405A
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