circulation, eliminate air pockets, and permit the complete drainage of the
system. Changes in horizontal piping sizes shall be made through eccentric
reducing fittings.
3.2.2
Cleaning of Piping (Pre-Erection)
Thoroughly clean each section of pipe, fittings, and valves of all foreign
matter before erection as follows: hold each piece of pipe in an inclined
position and thoroughly tap along its full length to loosen sand, mill
scale and other foreign matter. Pipe 50 mm 2 inches and larger shall have
a wire brush of a diameter larger than that of the inside of the pipe drawn
through its entire length several times. Before final connections are made
to apparatus, wash out the interior of all piping thoroughly with water.
Plug or cap open ends of mains during all shutdown periods. Do not leave
lines open at any place where any foreign matter might accidentally enter
pipe.
3.2.3
Cleaning of Piping (Post-Erection)
Prior to the hydrostatic, performance and operating tests, the interior of
the heat-carrying piping shall be flushed with water until the piping is
free of all foreign materials to the satisfaction of the [Contractor
Quality Control representative] [Contracting Officer].
3.2.4
Valves
3.2.4.1
General
Install valves in conformance with ASME B31.1 and as required herein at the
locations indicated. Install valves with stems horizontal or above. Locate
or equip stop valves to permit operation from floor level, or provide with
safe access in the form of walkways or ladders. Install valves in
positions accessible for operation and repair.
3.2.4.2
System Terminal Unit Piping
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NOTE: Ascertain that the flow in the hot water side
(shell) is continuous to preclude overheating, that
the hot water supply side is provided with
appropriate safety relief valve piped to drain, and
that any necessary alarms and flow switches are
provided on the hot water supply of the heat
exchanger. Ascertain also that the high or medium
temperature water is on the tube side of the heat
exchanger and hot water on the shell side.
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NOTE: The following information shall be shown on
the project drawings:
1. Flow diagram of high or medium temperature water
piping indicating connections to existing supply and
return, pressure and temperature of existing supply
and return, (maximum and minimum or constant,
applicable), valves and critical valve positions
(including normally closed for bypass valve), any
necessary flow rates, pressure drops not already in
SECTION 15184N
Page 16
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