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|  MIL-P-18472G(SH)
subjected to the endurance test and subsequently restored and shop tested and
that It shall be certified as fully conforming to the specification for
unrestricted service.
4.6.3.2 Shock test. The pump shall undergo a shock test to ascertain that
the pump has the necessary shock resistance. The shock test shall be performed
in accordance with MIL-S-901 and the specific shock test requirements specified
herein.
4.6.3.2.1 Before and after the shock test the pump and driver and other
components susceptible to internal derangement shall be disassembled to the
extent necessary and the critical dimensions and running clearances measured,
calculated, and recorded. During this disassembly the critical components and
assemblies subject to shock damage and derangement shall be identified and listed
in the inspection record and after completion of the test the condition of each
component and assembly shall be determined and recorded. Shafts, impellers and
turbine rotors shall be inspected by one of the applicable nondestructive test
procedures, other than radiography, specified in MIL-STD-271.
4.6.3.2.2 Before and after the shock test, shop tests in accordance with
4.6.1.3 shall be performed to determine the changes in performance characteris-
tics of the pump. Vibration measurements shall be taken at the bearing caps or
housings of the pump and driver at equal speeds during the initial and final
capacity test to determine the changes in mechanical operation.
4.6.3.2.3 The unit shall be mounted on the shock machine or barge essen-
tially identical to the actual shipboard installation. The contracting activity
will furnish the contractor a drawing of the shipboard mounting arrangement.
Horizontal pumps when tested in the inclined position on the medium weight shock
machine shall be oriented so that the direction of shock is perpendicular to the
axis of pump rotation. The pump shall be in operation during the first and third
blow in each orientation on the medium weight shock machine. The pump shall be
in operation during the first, third and fifth blows of the shock test on the
floating barge. Variable speed pumps shall be operated at minimum speed and
pressure required to ensure lubrication of bearings and wearing parts. Other
pumps shall be operated at the lowest rated speed.
4.6.3.2.4 The pump shall be carefully observed during each shock blow and
thoroughly examined visually after each blow. After each blow the unit shall be
operated at as close to maximum rated speed as possible and checked for abnormal
noises and vibration and proper functioning of controls. Turbine driven pumps
may be air driven.
4.6.3.2.5 Shock test acceptance criteria:
(a) There shall be no breakage of parts, including mounting bolts.
(b) There shall be no distortion or derangement of any part which
would render the unit incapable of performing as specified,
(c) The amplitude of vibration after test at q aximum rated speed shall
be less than twice the amplitude measured at the same speed
before the test.
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