5.3.1 Each type of piping component
should be subject to type tests.
5.3.2.1 Each size and type
of valve intended to be used at a working temperature below -55°C
should be subjected to a tightness test to the minimum design temperature
or lower, and to a pressure not lower than the design pressure of
the valve. During the test the satisfactory operation of the valve
should be ascertained.
5.3.2.2 The following type
tests should be performed on each type of expansion bellows intended
for use on cargo piping outside the cargo tank and, where required,
on those expansion bellows installed within the cargo tanks:
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.1 A type element of the bellows, not precompressed,
should be pressure tested at not less than five times the design pressure without
bursting. The duration of the test should not be less than five min.
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.2 A pressure test should be performed on a type
expansion joint complete with all the accessories such as flanges, stays and
articulations, at twice the design pressure at the extreme displacement conditions
recommended by the manufacturer without permanent deformation. Depending on the
materials used, the Administration may require the test to be at the minimum
design temperature.
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.3 A cyclic test (thermal movements) should be
performed on a complete expansion joint, which is to successfully withstand at
least as many cycles, under the conditions of pressure, temperature, axial
movement, rotational movement and transverse movement, as it will encounter in
actual service. Testing at ambient temperature is permitted, when this testing is
at least as severe as testing at the service temperature.
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.4 A cyclic fatigue test (ship deformation) should be
performed on a complete expansion joint, without internal pressure, by simulating
the bellows movement corresponding to a compensated pipe length, for at least
2,000,000 cycles at a frequency not higher than 5 cycles/s. This test is only
required when, due to the piping arrangement, ship deformation loads are actually
experienced.
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.5 The Administration may waive performance of the
tests referred to in this paragraph provided that complete documentation is
supplied to establish the suitability of the expansion joints to withstand the
expected working conditions. When the maximum internal pressure exceeds 1.0 bar
gauge this documentation is to include sufficient test data to justify the design
method used, with particular reference to correlation between calculation and test
results.