No special requirements.
Checking of the welds shall be carried out in accordance with the λ=1 requirements of 6.8.2.1.23.
By derogation from the requirements of 6.8.2.4.2, the periodic inspections shall take place:
at least after six years | at least after eight years |
The intermediate inspections according
to 6.8.2.4.3 shall be carried out at least
six years after each periodic inspection.
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A leakproofness test or an intermediate inspection
according to 6.8.2.4.3 may be performed, at the request
of the competent authority, between any two successive
periodic inspections.
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The reference holding time for tank-containers carrying
refrigerated liquefied gases shall be determined on the
basis of the following:
(a) The effectiveness of the insulation system,
determined in accordance with 6.8.3.4.11;
b) The lowest set pressure of the pressure limiting
device(s);
(c) The initial filling conditions;
(d) An assumed ambient temperature of 30 °C;
(e) The physical properties of the individual
refrigerated liquefied gas intended to be carried.
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The effectiveness of the insulation system (heat influx in
Watts) shall be determined by type testing the tankcontainers.
This test shall consist of either:
(a) A constant pressure test (for example at atmospheric
pressure) during which the loss of refrigerated
liquefied gas is measured over a period of time; or
(b) A closed system test during which the rise in
pressure in the shell is measured over a period of
time.
When performing the constant pressure test, variations
in atmospheric pressure shall be taken into account.
When performing either test corrections shall be made
for any variation of the ambient temperature from the
assumed ambient temperature reference value of 30 °C.
NOTE: ISO 21014:2006 "Cryogenic vessels —
Cryogenic insulation performance" details methods of
determining the insulation performance of cryogenic
vessels and provides a method of calculating the holding
time.
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