2.2.2
Drums
Drums shall conform to FS F-B-2902 and requirements herein. Provide
sufficient drum-internals to preclude thermal shock, ensure steam quality
as specified herein, Ensure drum capacity addresses expected load swings to
insure maintenance of drum level within set points during high load swings,
and to properly condition the water in accordance with chemical feed and
blowdown systems specified [indicated] [and] [specified]. Nuts, bolts, and
other hardware used in assembling steam separators shall be stainless
steel. Where drum internals interfere with inspection of part of the
boiler drum, make provisions for the easy removal and replacement of
whatever internals must be removed in order to effect a complete internal
drum inspection and to provide access to tubes. Construct lower drums to
preclude build-up of suspended solids, and to permit the complete drainage.
2.2.3
Tubes
Boiler and furnace tubes shall meet the applicable requirements of FS
F-B-2902. Tangent tubes or tubes with welded flat studs or a combination
thereof shall be provided for water cooling of the furnace rear wall, side
walls, roof, and floor. Maximum tube spacing for tubes with welded flat
studs should be given so that the problem of studs driving through tube
sidewalls due to expansion and contraction does not occur. Burner wall
shall be refractory-covered with optional tubes for water cooling. Tubes
shall enter the steam drum below the normal water line.
2.3
Boiler Trim
Boiler trim, including steam stop valves, feedwater stop and check valves,
blowoff valves, water level indicators, water columns, pressure gages,
safety valves and associated piping, and fittings located within the
jurisdictional limits of the ASME Code shall conform to and be installed in
accordance with the Code and shall meet supplemental requirements specified
herein. Material selection and pressure ratings for valves and piping
shall be in accordance with applicable ANSI standards cited in the ASME
Code and shall be based on the maximum allowable boiler working pressure
specified herein except as otherwise permitted by the ASME Code.
2.4
Boiler Instrumentation
In addition to the instruments required by the boiler specification
referenced above, provide the following instruments:
a.
Temperature gages to indicate temperature of [preheated oil] [air
preheater inlet and outlet air][steam temperature].
b.
Meters for indicating air flow, drum level and indicating,
recording, and totalizing steam and fuel flow. Installation and
calibration of these meters shall confirm to ASME PTC 19.5.
c.
Instruments to indicate and record flue gas temperature.
d.
A draft gage, diaphragm or bellows type, conforming to ASME B40.1.
Circular scale with graduations in Pa inches of water. Numerals
shall be suitable for reading by persons with normal vision from a
distance of 6 meters 20 feet. Select range for intended service
and contain completely within the calibrated range. Encompassing
no more than 80 percent of the total range. Gages shall be
designed and constructed to ensure accuracy within plus or minus 2
SECTION 15517N
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