3.1.2.11
Reduction in Pipe Size
Provide reducing fittings for changes in pipe size; bushings will not be
permitted. In horizontal steam lines, reducing fittings shall be the
eccentric type to maintain bottom of lines in the same plane. In
horizontal water mains, reducers shall be set to maintain top of lines in
the same plane.
3.1.2.12
Expansion Control
Provide bends, loops, and offsets wherever practical to relieve
overstressed piping systems due to thermal expansion and to provide
adequate flexibility. Cold spring piping system as indicated but not more
than 50 percent of the total linear expansion.
3.1.2.13
Connection to Equipment
Provide unions or flanges where necessary to permit easy disconnection of
piping and apparatus. Provide unions and gate valves at each connection to
threaded end control valves, strainers and equipment.
3.1.2.14
Valve Installation
Install valves in positions accessible for operation and repair. Install
stems in a vertical position with handwheels or operators on top or in a
horizontal position. Do not install handwheels on stop valves below the
valve. When centerline of valve is more than 2 meters 7 feet above floor
or platform, provide valve with a chain-operated handwheel. When valve is
motorized, provide hand operation for emergency use.
a.
Gate Valves: Arrange back outlet gate valves for turbine exhaust
for hand operation and provide with a floor stand.
b.
Globe Valves: Pressure shall be below the disc. Install globe
valves with stems horizontal on steam and exhaust lines, when
better drainage is required or desired.
c.
Steam Pressure-Reducing Valves: Provide steam line entering each
pressure-reducing valve with a strainer. Provide each
pressure-reducing valve unit with two shutoff valves and with a
globe or angle bypass valve and bypass pipe. A bypass around a
reducing valve shall be of reduced size to restrict its capacity
to approximately that of the reducing valve. Provide each
pressure-reducing valve unit with indicating steam gages to show
reduced pressure and upstream pressure and an adequately sized
safety valve on low pressure side.
d.
Valve Tags and Charts: Permanently tag each valve with a black
and white engraved laminated plastic tag showing valve number,
valve function and piping system and whether another valve must be
opened or closed in conjunction with this valve. Furnish a typed
chart which will show required valve tagging plus the location of
each valve. Frame valve charts under glass and install as
directed.
3.1.2.15
Traps and Connections
Traps shall be of the type and capacity for the service required, and shall
SECTION 15501N
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