steel base and chair rings, and clean-out door.
a.
Construction: Acid resistant lined steel stacks shall be
fabricated of [ASTM A 242/A 242M, Type 1] [ASTM A 36/A 36M]
structural steel plate with a 1.60 mm 1/16 inch corrosion
allowance. Design shall include a static analysis of stack of
wind loadings and critical wind velocity and dynamic analysis of
stack including damping of vortex shedding and seismic response.
Minimum steel plate thickness of stack shall not be less than 6 mm
1/4 inch. Stack sections shall be of welded construction and
fabricated in sections not to exceed normal shipping limitations.
Longitudinal seams shall have full penetration, continuous
butt-welded joints. The section or horizontal joints of the stack
shall also be full penetration continuous buttwelds. Welding
shall be done by certified welders. Secure the stack to the
foundation by a base plate with gussets, counterforts or steel
beams provided as required. A reinforced concrete foundation, the
design of which shall be approved by the stack manufacturer, shall
be provided. Base construction of the stack shall transmit forces
and moments in the shell to the [foundation] [supporting steel]
without local stresses of appreciable magnitude being induced in
the shell or exceeding the allowable stresses of the supporting
[concrete] [steel].
b.
Stack-Breeching Connection: A lined breeching connection of the
same wall thickness as the stack shall be welded to the stack and
the steel jacket of the stack reinforced as required to compensate
for the structural strength of steel removed. A flange for
bolting breeching to the connection shall be provided. A hinged
cast iron or steel cleanout door with refractory lining and heavy
duty steel frame shall be provided at the bottom of the stack.
Frame and door shall be fitted gastight. Door shall be a minimum
of 457 by 610 mm 18 by 24 inches in size.
c.
Block Lining: Provide a lining consisting of inorganic
borosilicate glass blocks bonded to the steel. Entire inside of
each stack shall be sandblasted to a white metal blast finish.
Block shall be 40 mm 1 1/2 inches thick, constructed of totally
organic-free closed cell borosilicate glass. Blocks shall be
shaped to reasonably match the inside of the stack and beveled to
match adjacent blocks such that no gaps between surfaces shall be
greater than 3 mm 1/8 inch. Blocks shall be bonded to the steel
and adjacent blocks with a two compound, urethane adhesive
membrane. Adhesive membrane shall be trowelled to both the steel
and block. Blocks shall be pressed into place in accordance with
the manufacturer's instructions to provide a bond free of voids.
d.
Optional Stack Lining: In lieu of the borosilicate glass block
lining specified above an acid resistant cast insulating
refractory lining with an acid resistant membrane liner over an
anchoring system may be provided. Lining system shall be suitable
for use in the pH range of 1.6 to 8. Liners composed of calcium
aluminate or calcium silicate will not satisfy service
requirements of the stack system.
(1) Membrane Liner: Urethane-Asphalt, or suitable similar
material, which has been used successfully in similar
installations to protect stacks from acid attack when flue gas
temperatures are below their dew point. Service temperature range
SECTION 15502N
Page 89
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