considered to be self-cleaning.
a.
A duct at an angle greater than 45 degrees to the horizontal plane
with gas flowing downward.
b.
A duct at an angle greater than 60 degrees to the horizontal plane
with gas flowing upward.
c.
A duct with hopper-shaped bottom and a conveyor[ specified in
Section 15863N FABRIC FILTER DUST COLLECTOR OF FLYASH PARTICLES IN
FLUE GAS to remove the settled dust].
2.2.6.2
Flue Gas Velocity
Flue gas design velocities in ductwork shall be calculated at the design
flow range specified in paragraph, "Dust Collector Data." The design
velocities in self-cleaning ducts shall be between 1372 and 1524 m/s 4,500
and 5,000 fpm. Where a possibility of dust settling exists, the design
velocity shall be 1676 to 1829 m/s 5,500 to 6,000 fpm. The design velocity
of clean gas shall be greater than 1219 m/s 4,000 fpm.
2.2.7
Draft Connections
Provide a 25 mm one inch capped connection in flue gas inlet and outlet
breech of dust collector(s) for determining differential pressure across
collector(s). Orient these connections so as to be accessible from access
platform or walkway specified herein.
2.2.8
Inlet Manifold and Dampers
**************************************************************************
NOTE: Specify or indicate air pressure available
for pneumatic operators or electrical
characteristics available for electric operators.
**************************************************************************
Provide, specially made for the dust collector, a steel plate flue gas
inlet manifold to provide single, flanged inlet connection. Furnish this
manifold with sectionalizing dampers with [pneumatic] [electric motor]
operators suitable for remote-manual operation. Dampers shall be
guillotine type not louver type.
2.2.9
Access
2.2.9.1
Access Structures and Fixtures
Platforms, Walkways, Stairways, Handrails, Kickplates and Fixed Ladders:
that are required for operation, examination, testing and maintenance of
each dust collector and shall be provided with each dust collector.
Platforms, walkways, stairways, handrails, kickplates and fixed ladders
shall be factory or shop fabricated, shall provide suitable access to all
openings in the hopper, and shall meet OSHA 29 CFR 1910-SUBPART D for
safety of maintenance and operating personnel. Walkways shall be provided
for maintenance and inspection of maintenance points. Walkways shall be
located not more than 1.22 meters 4 feet directly below the centerline of
collector striker plates and the centerline of [the] [each] access door to
[the] [each] hopper. Walkways and platforms shall be connected by
stairways or fixed ladders. Supporting steel for platforms, fixed ladders
and walkways shall be designed for the live load specified herein.
SECTION 15861N
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