13.3.1 Except as provided
in 13.3.2, each cargo tank should
be fitted with a high liquid level alarm operating independently of
other liquid level indicators and giving an audible and visual warning
when activated. Another sensor operating independently of the high
liquid level alarm should automatically actuate a shutoff valve in
a manner which will both avoid excessive liquid pressure in the loading
line and prevent the tank from becoming liquid full. The emergency
shutdown valve referred to in 5.6.1 and 5.6.3 may be used for this purpose. If
another valve is used for this purpose, the same information as referred
to in 5.6.4 should be available on
board. During loading, whenever the use of these valves may possibly
create a potential excess pressure surge in the loading system, the
port State authority may agree to alternative arrangements such as
limiting the loading rate, etc.
13.3.2 A high liquid level
alarm and automatic shutoff of cargo tank filling need not be required
when the cargo tank:
-
.1 is a pressure tank with a volume not more than 200
m3; or
-
.2 is designed to withstand the maximum possible
pressure during the loading operation and such pressure is below that of the
start-to-discharge pressure of the cargo tank relief valve.
13.3.3 Electrical circuits,
if any, of level alarms should be capable of being tested prior to
loading.