15.7.1 Phosphorus shall,
at all times, be loaded, carried and discharged under a water pad
of 760 mm minimum depth. During discharge operations, arrangements
shall be made to ensure that water occupies the volume of phosphorus
discharged. Any water discharged from a phosphorus tank shall be returned
only to a shore installation.
15.7.2 Tanks shall be designed
and tested to a minimum equivalent water head of 2.4 m above the top
of the tank, under designed loading conditions, taking into account
the depth, relative density and method of loading and discharge of
the phosphorus.
15.7.3 Tanks shall be so
designed as to minimize the interfacial area between the liquid phosphorus
and its water pad.
15.7.4 A minimum ullage space
of 1% shall be maintained above the water pad. The ullage space shall
be filled with inert gas or naturally ventilated by two cowled standpipes
terminating at different heights but at least 6 m above the deck and
at least 2 m above the pump-house top.
15.7.5 All openings shall
be at the top of cargo tanks, and fittings and joints attached thereto
shall be of materials resistant to phosphorus pentoxide.
15.7.6 Phosphorus shall be
loaded at a temperature not exceeding 60°C.
15.7.7 Tank heating arrangements
shall be external to tanks and have a suitable method of temperature
control to ensure that the temperature of the phosphorus does not
exceed 60°C. A high-temperature alarm shall be fitted.
15.7.8 A water drench system
acceptable to the Administration shall be installed in all void spaces
surrounding the tanks. The system shall operate automatically in the
event of an escape of phosphorus.
15.7.9 Void spaces referred
to in 15.7.8 shall be provided
with effective means of mechanical ventilation which shall be capable
of being sealed off quickly in an emergency.
15.7.10 Loading and discharge
of phosphorus shall be governed by a central system on the ship which,
in addition to incorporating high-level alarms, shall ensure that
no overflow of tanks is possible and that such operations can be stopped
quickly in an emergency from either ship or shore.
15.7.11 During cargo transfer,
a water hose on deck shall be connected to a water supply and kept
flowing throughout the operation so that any spillage of phosphorus
may be washed down with water immediately.
15.7.12 Ship-to-shore loading
and discharge connections shall be of a type approved by the Administration.