2.9.2
Breeching Connection
Provide a breeching connection of the same thickness as the stack and weld
to [the] [each] stack and reinforce the stack externally with steel plates
and/or structural members as required to compensate the stack for the
structural strength of the metal removed. Provide a flange for bolting
breeching to this connection. Provide a hinged cast-iron or steel cleanout
door with a heavy duty cast steel frame at the bottom of each stack. Frame
and door shall be fitted gas-tight. Doors shall be a minimum of 457 by 610
mm 18 by 24 inches in size.
2.9.3
Lining
Stack lining shall be an alumina-silica-base castable insulating refractory
of the hydraulic setting type certified by the manufacturer to be suitable
for the specific application, considering the flue gas temperature,
velocities, moisture content, and corrosive qualities of the fuel being
burned, applied to each stack under the direct supervision of a qualified
representative of the manufacturer. The lining thickness shall be 76 mm 3
inches. Stack base plate exposed inside of each stack shall be covered
with castable insulating refractory as specified for stack lining. Boiler
stack lining shall have a minimum pyrometric cone equivalent (PCE) of 10
1304 degrees C 2380 degrees F with a maximum installed dry weight of 720
kilogram per cubic meter 45 pounds per cubic foot and a recommended service
temperature of 1093 degrees C 2000 degrees F. The top 3 meters 10 feet of
lining shall be a dense castable refractory 1840 kilograms per cubic meter
115 lb/ft 3 suitable for all weather and flue gas temperature conditions
encountered in the top of stacks. Stack lining shall be fastened to each
stack with heat and corrosion resistant alloy metal anchors which maintain
their structural strength up to 760 degrees C 1400 degrees F. Anchor clips
shall be spaced vertically not greater than 610 mm 24 inches on centers and
closer horizontally as required by diameter of the stack. Types, size, and
number per section shall be randomly located by the stack and refractory
manufacturer to adequately support refractory lining to permit expansion
and prevent cracking of refractory. A 50 mm 2 inch mesh galvanized wire
screen of 8 gage (4.10 mm) (0.1620 inch) wire shall be attached to the
clips for reinforcing the refractory. Locate screen at midpoint of the
refractory thickness and cover end of clips with at least 25 mm one inch of
refractory.
2.9.4
Stacks
Clean stacks of dirt, rust, oil, and grease by wire brushing and solvent
degreasing and given one shop coat of heat-resisting aluminum paint
conforming to FS TT-P-28 on the inside and outside. The coat of paint
shall have a minimum dry film thickness of 0.025 mm one mil.
2.10
BLOWDOWN EQUIPMENT
Furnish [the boiler] [the plant] with equipment, tanks, and controls
necessary for bottom [and continuous] blowdown of the boiler(s). The
equipment for bottom blowdown systems shall include a [blowdown tank] [and
sample cooler]. [Continuous blowdown systems shall be of the packaged,
proportional type consisting of a heat exchanger, flow control valve, surge
Install and pipe blowdown equipment as indicated and it shall conform to
the recommendations of the NBBPVI NB-27.
SECTION 15517N
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