shall be 3/4 mm 1/32 inch between adjacent holes and 1 1/2 mm 1/16 inch
between any two holes on a side in the flange pattern after fabrications of
the complete ductwork section. After fabrication of the ductwork section,
measurement shall be made between holes across diagonals and bracing shall
be installed to maintain flange bolt tolerance. Provide connections for
temperature and pressure measurements as specified and as required of the
control of the FGD system. Instrument connections shall be 50 mm 2 inch
Schedule 40 pipe with screw caps and shall extend 150 mm 6 inches beyond
the insulation and lagging on the ductwork. Instrument connections shall
be provided with rod-out caps or plugs. Maximum plan width inside
dimension of the breeching at interface with the chimney shall be [_____].
2.11.1.1
Reverse Air Ductwork
Reverse air ductwork shall be constructed of sheet steel and all seams and
connections shall be airtight. Means shall be provided to maintain the
temperature in the reverse air ductwork above the dewpoint by circulation
of clean flue gas.
2.11.2
Expansion Joints
**************************************************************************
NOTE: Dry and Wet Bulb Temperature and Duration:
Temperature
Frequency of Occurrence
Parameter
Season
(Degrees C)
of Higher Temperatures
Dry Bulb
Dec.-Feb.
[______]
[______]
Dry Bulb and
June-Sept.
[______]
[______]
Mean Coincident
Wet Bulb
Wet Bulb
June-Sept.
[______]
[______]
Temperature
Frequency of Occurrence
Parameter
Season
(Degrees F)
of Higher Temperatures
Dry Bulb
Dec.-Feb.
[______]
[______]
Dry Bulb and
June-Sept.
[______]
[______]
Mean Coincident
Wet Bulb
Wet Bulb
June-Sept.
[______]
[______]
**************************************************************************
Expansion joints shall be nonmetallic belt-type joints. Expansion joints
shall be suitable for maximum expected or specified working pressures and
for operation at design gas-flow velocities. Expansion joints shall
include baffles able to withstand a fallout ash weight of 976 kg/sq m 200
lbs/sq ft and remain completely workable. Expansion joints shall be
designed for temperature from [_____] to [_____] degrees C degrees F.
Provide access to four sides of expansion joints, both interior and
exterior to the ductwork. Each expansion joint shall include: minimum 80
by 80 by 6 mm 3 by 3 by 1/4 inch carbon steel angle flanges drilled for
mounting to ductwork for joints where belt does not have molded flanges, a
carbon steel backing bar, and internal baffle around full circumference of
SECTION 15864N
Page 71
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