2.23.14
Coal Storage Silos
2.23.14.1
Silo Walls
Silo walls may be slip-formed, cast-in-place reinforced concrete, precast
concrete, or other approved construction materials. Concrete shall have a
28-day compressive strength in accordance with Section 03300A CAST-IN-PLACE
STRUCTURAL CONCRETE. Silo roof shall be reinforced concrete complete with
600 mm 24 inch square, weatherproof, hinged access door. Handrail and
steel toe-board shall be provided all around roof of the silo. Live
storage shelf for the silo shall be reinforced concrete sloped not less
than 60 degrees from horizontal and supported by steel beams corbelled from
the inside walls of the silo. Live storage outlet hopper to chute and
feeders shall be built of not lighter than 9.5 mm 3/8 inch steel. Silo
reserve storage floor shall be reinforced concrete, sloped not less than 60
degrees and laid on well-tamped fill material. Reclaim outlet hopper to
the chute feeding the flight feeder shall be built of not lighter than 9.5
mm 3/8 inch steel.
2.23.14.2
Concrete Stave Silo
In a concrete stave silo, the interior finish shall consist of a three-coat
concrete parget. A brush coat, scratch coat, and a finish trowel coat
shall be applied, one after the other, to produce a smooth monolithic
finish. The parget shall be worked into the vertical and horizontal
grooves to permanently interlock the concrete staves.
2.23.14.3
Exteriors of Stave And Concrete Silos
The exteriors of stave and concrete silos shall be covered with a brush
coat of gray cement. This coating shall be applied over all hoops, lugs,
and staves to produce a homogeneous finish.
2.23.14.4
High- and Low-Level Switch
A normal high-level and emergency high-level control switch shall be
mounted at the top of the silo to shut off the feeding system when the silo
is full of coal. A low-level switch shall be furnished at the low level of
the silo's live storage shelf, as indicated, to signal by light that coal
is at a low level in the live storage compartment. Switches shall also be
furnished near the bottom of the silo, as indicated, to signal by light
that coal is at a low level in the reserve storage compartment. Switches
shall be for Class II, Division 1, Group F hazardous location in accordance
with NFPA 70.
2.23.15
Coal Crusher
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NOTE: Where motor starters for mechanical equipment
are provided in motor control centers, delete the
description of motor starters.
The designer shall select the appropriate type of
crusher, based on the throughput requirements and an
economic analysis.
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Coal crusher shall be [roll crusher] [hammermill] maximum lump size of
[_____] mm inches. Crusher shall have a minimum capacity of [_____] metric
SECTION 15555A
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