PIPE END DIAMETER TOLERANCE
TOLERANCE
NOMINAL PIPE SIZE
ON ACTUAL O.D.
mm (in.)
mm (in.)
Less than or equal
to 400 (16)
Plus/minus 1.5 (0.06)
400 (16) to 600 (24)
Plus/minus 2.0 (0.08)
600 (24) to 1050 (42)
Plus/minus 2.5 (0.10)
Greater than 1050 (42)
Plus 3.0 (0.12)/
Minus 1.5 (0.06)
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Make column and discharge elbow of [either cast iron, cast steel, or welded
steel plate] [stainless steel plate]. [Steel plate, if used,][Stainless
steel plate] shall have thickness of not less than [_____] mm inch after
machining is completed. Elbow shall be of [short radius type][long radius
type][mitered type].[ Turning vanes shall not be used.][ Turning vanes,
if used, shall be spaced apart at least twice the space of clear space of
trashrack.] Column and discharge elbow shall be designed to withstand
internal pressures and external loadings associated with various conditions
of pump operation. Provide flanges for mating individual segments together
and for mating pump column to diffuser bowl. Flanges shall have rabbeted
fits or four equally spaced dowels installed in flanges for initial
alignment purposes and to maintain concentric alignment. The elbow shall
terminate in a plain-end circular section. Diameter tolerance of plain end
shall be [_____] mm inch. Diameter of discharge end of elbow shall be as
shown and shall allow standard diameter flexible couplings to be used.
Adjustable thrust rods and thrust lugs shall be used to transfer the load
by bridging the coupling.
2.2.7.2
Column and Discharge Elbow Support
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NOTE: Select appropriate alternate paragraph. Pump
Column and Discharge Elbow (Alternate 1) is used for
conventional pumps supported from the base plate.
Design Pump Unit (Alternate 2) is used for large
stations having pumps over 1800 mm (72 in.) in
discharge diameter and supported from different
floors.
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[Pump column and discharge elbow shall be designed for suspension from a
baseplate assembly specified in paragraph BASE PLATE AND SUPPORTS and
located at operating floor level.]
[Design pumping unit for installation as shown. Baseplate for supporting
[electric motor] [gear reducer] shall be at elevation of operating floor,
EL [_____]. Pump casing shall be supported at intermediate floor, EL
[_____]. Furnish [support system] [support system consisting of columns
extending from baseplate to intermediate floor]. Support system shall
transfer entire load on baseplate to intermediate floor. Design support
system to maintain proper alignment of pumping unit and propeller blade
setting. Include support system in the dynamic analysis.]
SECTION 15131A
Page 25
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