2.5
PIPING AND FITTINGS
2.5.1
General Requirements
Piping, fittings and piping accessories inside the valve manholes shall
conform to the requirements of ASME B31.1 and shall be suitable for the
working pressure and temperature requirements of the system. To the
greatest extent possible, the piping and fittings inside the valve manholes
shall match the piping and fittings located on the outside of the valve
manhole. All piping in valve manholes shall be steel with joints welded
except that joints 20 mm 3/4 inch and smaller may be threaded. When
threaded joints are used on High Temperature Water Systems, the interface
area where the pipe threads meet the threaded fittings shall be seal welded
(continuous fillet weld) to preclude any water leakage. No supports,
anchors, or stays shall be attached to any piping system in places where
either the installation of or the movement of the pipe and its contents
will cause damage to the construction.
2.5.2
Steel Pipe
Pipe shall be black steel, seamless or electric-resistance welded,
conforming to the requirements of ASTM A 53/A 53M, Grade B or ASTM A 106/A
106M, Grade B. Pipe up to and including 250 mm 10 inches in diameter shall
be schedule 40. Pipe 300 mm 12 inches in diameter and greater shall be 10
mm 0.375 inch nominal wall thickness. Gauge piping [, condensate piping,]
[drip piping,] and piping 20 mm 3/4 inch in diameter and smaller shall be
schedule 80.
2.5.2.1
Nipples
Nipples shall conform to ASTM A 733 as required to match adjacent piping.
2.5.2.2
Pipe Threads
Pipe threads shall conform to ASME B1.20.1. Pipe threads may be used only
on pipe 20 mm 3/4 inch or smaller. All pipe which is to be threaded shall
be schedule 80.
2.5.3
Fittings
All fittings, valves, flanges and unions shall have the manufacturer's
trademark affixed in accordance with MSS SP-25 so as to permanently
identify the manufacturer.
2.5.3.1
Welded Fittings
Welded fittings shall conform to ASTM A 234/A 234M, buttwelded or socket
welded, as required to match connecting piping. Buttwelded fittings shall
conform to ASME B16.9, and socket welded fittings shall conform to ASME
B16.11.
2.5.3.2
Unions
Unions shall conform to MSS SP-83 as required to match adjacent piping.
2.5.3.3
Ball valves shall conform to MSS SP-72 for flanged or buttwelded valves or
MSS SP-110 for threaded ball valves.
SECTION 02560
Page 11
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