**************************************************************************
Motor for driving forced draft fan shall be [variable speed] [two speed],
[_____] volt, three phase, 60 Hz, [open drip-proof] [totally enclosed, fan
cooled] not less than [_____] kW hp, as specified in paragraph entitled
"Motors and Drives," and shall not overload at the specified capacity with
unheated cold air. Provide [_____] mm inch thick steel soleplate for
motor. Soleplate shall be common for all four motor mounting bolts.
Separate parallel soleplate bars are not acceptable.
2.6.1.4
Noise Level for Forced Draft Fan
Not to exceed 85 dBA sound pressure level at 1 1/2 meters 5 feet above
floor and 1 1/2 meters 5 feet from fan in any direction. Provide heavy
duty sound attenuator with screen on fan inlet when required to meet sound
pressure level requirements.
2.6.2
Induced Draft Fan
FS W-F-2793, Type [_____], Class 2 except as specified otherwise.
2.6.2.1
Fan Size
Size fans to handle combustion gases at maximum firing rate. Maximum fan
speed shall not exceed [_____] rpm at test block rating. Design allowances
and corrections for furnace, economizer, [scrubber,] [baghouse,] [dust
collector,] breeching pressure drop when operating at [10] [20] [40]
percent excess air, flue gas temperature, plant elevation and other design
factors shall be made. Add the following allowances for momentary
overloads and normal deterioration of fans, firing equipment and boilers
after sizing in accordance with the above, to obtain the required test
block rating:
Coal Fired
Excess Volume
Excess Pressure
Induced draft
20 percent
32 percent
Oil Fired
Induced draft
10 percent
20 percent
2.6.2.2
Fan Construction
Fan wheel shall be radial
tip design constructed of steel. Balance fan
wheel both statically and
dynamically at factory. Direction of fan
discharge shall be easily
changed at angles of 45 degrees. Provide fan
with [air] [water] cooled
sleeve type or roller bearings mounted in pillow
blocks.
2.6.2.3
Dampers
Provide inlet dampers with multi-parallel-stream flow blades with
anti-friction bearings with 80 mm 3 inch minimum spacers and stuffing boxes
to keep bearings cool. Dampers shall be mounted in 200 mm 8 inch channel
frames and interconnected with one extended, ball bearing mounted control
level for connection to control actuator.
SECTION 15501N
Page 56
Previous Page
