ranges. Provide external adjusting screw for adjustment throughout each
spring range. Provide internal pressure tap for outlet pressure regulation.
2.7
BREECHING, EXPANSION JOINTS, STACKS, AND DAMPERS:
2.7.1
Breeching
Provide with rectangular cross section and fabricate of not less than 5 mm
3/16 inch thick black steel plate unless otherwise noted. Stiffeners shall
be not less than 65 by 50 by 6 mm 2 1/2 by 2 by 1/4 inch steel angles
welded to exterior with 50 mm 2 inch leg outstanding. Stiffeners shall not
exceed one meter 3 feet on centers. Breeching shall connect to [each
boiler flue gas outlet,] [intermediate heat recovery equipment,] [air
pollution control equipment,] [and to stack as required].
2.7.1.1
Breeching Connections and Joints
Weld or bolt breeching joints unless indicated otherwise. Welding shall
conform to AWS D1.1/D1.1M and AWS D1.3. Bolts for bolted connections shall
be not less than 15 mm 1/2 inch diameter and spaced not more than 80 mm 3
inches apart, with bolts, lockwashers and nuts being hot-dipped galvanized.
Provide bolted joints with a minimum of 3 mm 1/8 inch thick gaskets. Bolt
breeching connections to boilers, equipment items, dampers, expansion
joints, and breeching accessories. Flanged breeching connections to
equipment shall be drilled to match flanges on equipment. Flanged joints
shall be seal welded to make connection gas-tight.
2.7.1.2
Uninsulated Breeching
Thoroughly wire brush breeching which is not to be insulated and clean by
degreasing with nonflammable solvent such as trichloroethylene prior to
painting.
2.7.1.3
Breeching Access Doors
Provide breeching access doors where indicated. Construct access doors
with frame and hinged door of cast iron or reinforced steel plate. Frame
shall be not less than 635 by 940 mm 25 by 37 inches with access opening of
457 by 762 mm 18 by 30 inches. Connection to breeching shall be gasketed
and made with minimum 15 mm 1/2 inch diameter hot-dipped galvanized bolts,
lockwashers, and nuts spaced not less than 127 mm 5 inches on center. Each
side of the access door shall have not less than two quick-clamp positive
closing latches, with the long side opposite the hinges containing three
clamps to give a gastight seal. Side of access door opposite hinges shall
contain a minimum 80 by 125 mm 3 by 5 inch size handle. Provide a gasket
consisting of 10 mm 3/8 inch diameter fire resistant resilient rope seal
and mastic compound between the access door and the access door frame.
2.7.1.4
Breeching Cleanout Doors
Provide breeching cleanout doors where indicated. Construct cleanout doors
of not less than 5 mm 3/16 inch thick steel plate. Secure cleanout doors
to a 32 by 32 by 5 mm 1 1/4 by 1 1/4 by 3/16 inch thick angle frame with 10
mm 3/8 inch hot-dipped galvanized mounting bolts welded to the angle frame
and spaced not more than 150 mm 6 incheso.c. Weld frame to breeching and
provide a 1.50 mm 1/16 inchgasket between frame and cleanout door.
Cleanout doors shall be not less than 610 mm 24 inches square except where
breeching dimensions are smaller, in which case the cleanout door shall be
full height of the breeching and not less than 305 mm 12 inches in length.
SECTION 15511N
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