b.
Valves for 150 pound class steel piping shall conform to the
following:
(1) Sizes 65 mm 2-1/2 inches and less, bronze:
MSS SP-80, Class
150 minimum.
(2) Sizes 80 mm 3 inches through 600 mm 24 inches, steel:
ASME
B16.34, Class 150 minimum, flanged ends, swing disc.
c.
Valves for system operating pressure greater than 1.4 MPa 200 psi
shall be swing check or lift check valves having a steel body and
shall be suitable for specified operating pressure, but not less
than Class 300 300 pound class. Valves 40 mm 1-1/2 inches and
smaller shall be cast or forged steel with socket welded ends.
Valves 50 mm 2 inch and larger valves shall be steel with butt
welded ends. Check valves shall have renewable composition discs
or shall have metallic discs of the regrindable type which permits
regrinding without removing valve from the line.
2.26.7.2
Gate Valves
Gate valves used as shutoff valves in the boiler leads to the steam
headers, and elsewhere as indicated, shall be of the chain-operated type,
with enough chain for easy operation from the operating floor or walkway.
Gate valves 200 mm 8 inches and larger used on high-pressure steam lines,
and elsewhere as indicated shall be provided with a globe valve bypass.
a.
Valves for 125 pound class steel piping shall conform to the
following:
(1) Sizes 65 mm 2-1/2 inches and less, bronze:
MSS SP-80, Type 1
or 2, Class 125.
(2) Sizes 80 mm 3 inches through 1200 mm 48 inches, cast-iron:
MSS SP-70, Type I, Class 125, Design OT or OF (OS&Y), bronze trim.
b.
Valves for 150 pound class steel piping shall conform to the
following:
(1) Sizes 65 mm 2-1/2 inches and less, bronze:
MSS SP-80, Type 1
or 2, Class 150 minimum.
(2) Sizes 80 mm 3 inches through 600 mm 24 inches, steel:
ASME
B16.34, Class 150 minimum, flanged ends.
c.
Valves for system operating pressure greater than 1.4 MPa 200 psi
shall be split wedge disc type, outside screw and yoke, steel and
shall be suitable for specified operating steam pressure, but not
less than Class 300 300 pound class. Valves 50 mm 2 inch and
smaller shall be forged steel with socket welded ends. Valves 65
mm 2-1/2 inches and larger shall be steel and shall have butt
welded ends.
2.26.7.3
Globe Valves and Angle Valves
Globe type valves shall have outside screw and yoke with bolted bonnets,
stainless steel trim, and flat seats, but shall not be the reversed cup
type. The stuffing boxes shall be large and deep. Valves shall be
installed with the stem horizontal or above.
SECTION 15559A
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