nuts. Minimum thickness of fabricated material shall be
[10][13][16][19] mm [3/8][1/2][5/8][3/4] inch for fabricated
portions. Provide grout holes in floor of the FSI to permit full
grouting.
d.
FSI connection to pump impeller bowl flange shall be designed by
the pump manufacturer and be rigid or flexible as indicated by
results of the dynamic analysis required in paragraph DYNAMIC
ANALYSIS. Submit design and drawings indicating materials of
construction and method of assembly of the FSI for approval.]
2.2.7.5
Flanges
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NOTE: The recommended minimum flange thickness to
be specified is:
MINIMUM
INSIDE DIAMETER OF JOINT
THICKNESS
mm (in.)
mm (in.)
Up to and including 600 (24)
32 (1-1/4)
From 600 (24) to and
including 1050 (42)
38 (1-1/2)
From 1050 (42) to and
including 2100 (84)
50 (2)
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Machine flanges and drill bolt holes concentric with pump shaft vertical
centerline, having tolerance of plus or minus one fourth of clearance
between bolt and bolt hole. When fabricated from steel plate, flanges
shall not be less than [25][32][38][50] mm [1][1-1/4][1-1/2][2] inch thick
after machining. Flange thickness after machining shall not vary more than
10 percent of greatest flange thickness. Provide external stiffeners, if
needed. Construct fabricated flanges, as a minimum, to the dimensions of
AWWA C207, Class B. Flanges on major components of pump casing (suction
bell, impeller bowl, diffuser bowl, and column and elbow piping) shall be
designed such that blind holes necessitating use of cap screws or stud
bolts will not be used. Design flanges for connection to column pipe by at
least two continuous fillet welds. One weld shall connect inside diameter
of flange to pump column and the other shall connect outside diameter of
pump column to flange. Final design of welds rests with manufacturer, and
specified welds are the minimum requirement. They shall be parallel
machined, when provided on each end of the same component, and mounted
parallel to a plane that is normal to pump shaft centerline. Flanges on
each end of the same component shall have parallel tolerance of 0.051 mm
0.002 inch. Finish machine mating surface on flange to 3.2 m 125
microinch finish or better. Provide flanges with minimum of three jacking
bolts to aid in disassembly of pump.
2.2.7.6
Design flanged joints to be air-and water-tight, without the use of
preformed gaskets, against positive and negative operating pressures that
will be experienced, except that "PERMATEX" or equal gasketing compound
will be permitted. Provide mating flanges, unless of the male-female
rabbet type, with not less than four tapered dowels equally spaced around
flange. If rabbeted fit is not used, then Contractor shall provide the
method used to determine concentricity of connected pieces.
SECTION 15131A
Page 28
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