including chain wheels, gear operators, floor stands, electric
motors, air motors and cylinder-type actuating devices. Provide
the accessories as follows and as indicated.
(1) Provide power operators with remote position indicators on
the following valves: soot blowers, [_____], [_____].
(2) Provide floor stands and valve extensions on platforms and
floors for the following valves: deaerator drain valves, [_____].
(3) Provide motorized actuators or chain wheels with chain and
guides on valves with handwheel centerline higher than 2 meters 7
feet above the floor or platform except where specified otherwise.
Chains shall extend from the valve to within one meter 3 feet
above the floor. Provide impact chain wheels on steam headers and
other locations where the valve has a tendency to stick. When a
valve is motorized, provide hand operation for emergency.
(4) Provide gear operators on ball valves larger than 80 mm 3
inches and on gate valves 200 mm 8 inches and larger.
f.
Steam pressure regulating valves: FS A-A-50558, minimum of Class
[125] [150] [250] [300], except as specified otherwise.
[Cast
iron], [cast steel] valve body with valve seats and disc of
replaceable heat treated stainless steel. Valves shall be single
seated, shall seat tight under dead end conditions, and shall go
to the closed position in the event of pressure failure of the
operating medium. Valves shall be spring loaded diaphragm
operated type, except valves exposed to ambient temperature of
less than 2 degrees C 35 degrees F or exposed to the weather shall
be piston operated type. Capacity of valves shall be not less
than that indicated. Pilot valves shall have strainer at inlet
from external feeder piping.
(1) Spring loaded diaphragm operated valves: Fabricate main
spring of stainless steel, and it shall not be in the path of
steam flow through the valve. Control valves by pilot valve
through external feeder piping.
(2) Piston operated valves: Control valves by integral pilot
valve through external feeder piping.
g.
Safety relief valves: MIL-V-18634, Style D or E, with Class [150]
[300] inlet flange, with test lever, designed for the intended
service.
2.15.1.5
Bolts and Nuts
a.
Bolts: ASTM A 193/A 193M, Grade B8. Lengths of bolts shall be
such that not less than two full threads will extend beyond the
nut with bolts tightened to required tensions and washers seated.
b.
Nuts:
ASTM A 194/A 194M, Grade 8.
2.15.1.6
Gaskets
ASME B31.1 and as specified below, except provide spiral wound metal
covered asbestos gaskets in lieu of compressed sheet asbestos. Gaskets
shall be as thin as the finish of surfaces will permit. Do not use paper,
SECTION 15502N
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