support steel, access ways and access doors shall be designed as specified
and as noted on the drawings. External and internal walls and partitions
of the ductwork shall be of fully sealed by continuous fillet or continuous
complete penetration groove welds, as applicable. Provide control
instruments and required penetrations as specified in paragraph entitled
"Instrumentation and Controls." Expansion joints shall be provided at
interface points of ductwork included in this contract and as required to
ensure that no stresses in ductwork and supports are transmitted to
equipment to be provided by the Contractor. Contracting Officer will
supply exact location, sizing and bolt hole patterns for connections at the
economizer outlet ductwork and chimney inlet. Furnish and deliver dampers
as indicated and as required for operation of FGD system including, but not
limited to, fabric filter baghouse module inlet and outlet dampers, fabric
filter baghouse bypass isolation dampers, induced draft fan inlet control
dampers, and guillotine system isolation system dampers. Furnish damper
units complete with operators and accessories and field service, as
specified. Dampers and louvers shall conform to AMCA 500-D, AMCA 801, and
AMCA 802. Provide mechanical draft equipment required for proper operation
of the flue gas cleaning systems and boilers including, but not limited to,
induced draft fans. Fans shall be complete with accessories and
auxiliaries specified. Provide fan inlet dampers as specified in paragraph
entitled "Dampers." Ductwork submittals shall include general arrangement
and outline information, foundation design information, structural
fabrication information, internal arrangement and erection information,
insulation and instrumentation information, and design calculations for
stiffener requirements for internal pressure ratings. Drawings shall show
details of ductwork connections, and layout and details as required for
access platforms, ladders, and handrails, details of each expansion joint,
details of slide bearing plates, and the expansion joint locations, the
movements to be absorbed in each joint, construction details and
flange-to-flange dimensions.
2.11.1
Ductwork
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NOTE: Dimension interface of ductwork and the
chimney to reduce pressure drop. Use maximum
dimensions.
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Ductwork shall be constructed with a minimum thickness of 6 mm 1/4 inch.
Ductwork shall be designed for a transient condition (80 percent of yield
strength) at internal pressure of at least plus 4980 and minus 7470 Pa 20
and minus 30 inches WC except as specified otherwise.
Joints and
seams shall be welded gas-tight by continuous fillet or continuous complete
penetration groove welds. Provide with access doors, as specified, to
provide access to each run of duct including both sides of dampers and gas
distribution devices. Ductwork shall be designed to withstand a fallout
particulate weight of 976 kg/square meter 200 lbs/sq ft. Provide 10 mm 3/8
inch thick-turning vanes for turns 45 degrees and greater and where
indicated by the model study. Properly brace and support with pipes and
angles. Bracing with rods is not permitted. Turning vanes are not
required in fabric filter baghouse manifold inlet and outlet transitions to
and from modules. Gas velocity of the main flue gas stream shall be as
specified in paragraph entitled "Ductwork." Provide gasket material bolts
and nuts for flanged connections. Gaskets shall be of ethylene propylene
terpolymer (EPDM) material. Provide flanges and expansion joints at ends
of scope to match equipment to be provided by the Contractor. Bolt hole
tolerance in flanges to be connected at interface points and to dampers
SECTION 15864N
Page 70
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