2.7.1.5
Breeching Structural Materials
**************************************************************************
NOTE: The designer shall detail breeching supports
and breeching stiffening. Breeching hangers shall
be designed to carry not less than 5 times the
breeching weight, or the breeching weight plus 136 kg
300 pounds whichever is greater. Hangers for
rectangular breeching shall be of the trapeze type
with angle or channel support members and hanger
rods. Breeching shall be stiffened with angle or
channel members as required to withstand internal
breeching static pressure.
**************************************************************************
Structural and support materials shall be steel and shall comply with the
applicable sections of AISC 335 or AISC 350. [Support and stiffen
breeching as indicated.]
2.7.2
Expansion Joints
2.7.2.1
Metallic Breeching Expansion Joints
Provide factory fabricated metallic breeching expansion joints [where
indicated]. Expansion joints shall be guided metal bellows type capable of
a minimum of [_____] mm inches of axial travel. Form metal bellows from
not less than 1.50 mm 1/16 inch thick type 321 stainless steel plate.
Cover plates shall be not less than 3 mm 1/8 inch thick steel plate.
2.7.2.2
Non-Metallic Expansion Joints
Provide factory fabricated non-metallic breeching expansion joints 3 mm 1/8
inch minimum thickness [where indicated]. Expansion joints shall be
constructed of fluoroelastomer vulcanized to two plies of knitted wire mesh
capable of a minimum of [_____] mm inches of axial compression, [_____] mm
inches of axial extension and [_____] mm inches of lateral offset [unless
indicated otherwise]. Joints shall have a continuous operating temperature
rating of 204 degrees C 400 degrees F, with excursion design standards up
to 400 degrees C 750 degrees F. Operating pressure range shall be minus 34
kPa (gage) to plus 34 kPa (gage) minus 5 psig to plus 5 psig. Expansion
joints shall be preformed with integrally molded corners, suitable for
mounting against a 150 mm 6 inch flange. Provide carbon steel backup bars
with slotted holes, bolts, and nuts.
2.7.3
Stacks (For Installation Without Flue Gas Scrubbers)
Stacks shall be free standing, dual wall with insulated annular space, self
supporting, steel construction. Contractor shall assure that the design of
the stack and supporting steel or concrete foundations meets or exceeds the
design conditions listed below. Provide each stack complete with
accessories and appurtances, including test ports, sampling platforms,
caged safety ladders, anchors, sleeves, insulation, base and chair rings,
and cleanout door.
2.7.3.1
Construction
a.
Air Space: Provide in the annular air space between the two steel
shells insulation with sealing means to accommodate thermal
SECTION 15511N
Page 44
Previous Page
