The locating of vanes in the water passage above the
diffuser bowl should be avoided; however, on pumps
with long columns where the use of intermediate
bearings is necessary, spiders or external supports
for the bearing housing may be permitted. A
shaft-enclosing tube, by itself, may not furnish the
needed support.
Alternate specifications for the "FACTORY TEST" have
been provided in this specification. Alternate 1
gives the manufacturer the option of testing either
the prototype pump or a homologous model of the
pump. This alternative should be used for all pumps
having a diameter up to and including 1200 mm (48
in.). Alternate 2, which requires a homologous
model of the pump be tested for performance and
NPSHR characteristics, should be used for pumps
having a diameter greater than 1200 mm (48 in.).
Alternate 2 can also be used for pumps smaller than
1200 mm (48 in.) in diameter if the expected annual
operating time is greater than 500 hours per year or
for the special case when there is no published
NPSHR curve available.
If this guide specification is used for a supply
contract, the flexible mechanical couplings and
harness bolts should be obtained under the
construction contract, except when the pump
manufacturer is required to furnish the discharge
piping.
With a construction contract, it is the prime
contractor's responsibility to have equipment
delivered when ready for installation. Inevitably,
delays occur. Some storage will most likely be
required. These requirements may be modified as
required, but in no case should they be deleted when
the storage of equipment is contemplated.
With a supply contract, the delivery of the
equipment being furnished should be arranged to
coincide with the date of installation, when
possible. This will obviate the need for long-term
storage of the equipment in Government-furnished
space.
This specification has been prepared on the basis
that it will be used in construction contracts. If
this guide specification is to be used for supply
contracts, paragraphs to be included in Part IV -
TECHNICAL PROVISIONS should be arranged to follow
the format listed below. Section 5 should be
deleted when a reduction gear is not to be
furnished, and the word "DELETED" should be
substituted in lieu thereof. Section 1 should
include appropriate provisions of UFGS-09964,
UFGS-05055A, and UFGS-05502A.
SECTION 15131A
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