13.5.1 Each cargo tank should
be provided with at least two devices for indicating cargo temperatures,
one placed at the bottom of the cargo tank and the second near the
top of the tank, below the highest allowable liquid level. The temperature
indicating devices should be marked to show the lowest temperature
for which the cargo tank has been approved by the Administration.
13.5.2 When a cargo is carried
in a cargo containment system with a secondary barrier at a temperature
lower than -55°C, temperature indicating devices should be provided
within the insulation or on the hull structure adjacent to cargo containment
systems. The devices should give readings at regular intervals and,
where applicable, audible warning of temperatures approaching the
lowest for which the hull steel is suitable.
13.5.3 If cargo is to be
carried at temperatures lower than -55°C, the cargo tank boundaries,
if appropriate for the design of the cargo containment system, should
be fitted with temperature indicating devices as follows:
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.1 A sufficient number of devices to establish that
an unsatisfactory temperature gradient does not occur.
-
.2 On one tank a number of devices in excess of those
required in 13.5.3.1 in order to verify that the initial cool down
procedure is satisfactory. These devices may be either temporary or permanent.
When a series of similar ships is built, the second and successive ships need not
comply with the requirements of this subparagraph.
13.5.4 The number and position
of temperature indicating devices should be to the satisfaction of
the Administration.