3.16.1 It is advisable that the main supply of
water to the inert gas scrubber as required in regulation 62.6.1 should be from an independent pump. The alternative
source of supply of water may be from another pump such as the sanitary,
fire, bilge and ballast pumps provided that the quantity of water
required by the inert gas scrubber is readily available and the requirements
of other essential services are not thereby impaired.
3.16.2 The requirement for two separate pumps
to be capable of supplying water to the deck water seal (see regulation 62.10.3) can be met by any of
the pumps referred to under alternative source of supply in 3.16.1 subject to the same provisions applying
as are recorded in that paragraph.
3.16.3 The pumps supplying water to the scrubber
and the deck water seal should be such as to provide the required
throughput of water under light draught conditions. The quantity of
water under all other draught conditions should not flood the scrubber
or increase the gas flow resistance excessively.
3.16.4 Loops in the piping of the deck water seal
to prevent the backflow of hydrocarbon vapour or inert gas should
be positioned outside the machinery space and suitably protected against
freezing, for example by steam tracing. With reference to the deck
water seal arrangement, provisions should be made to prevent a pneumatically
controlled system from freezing (see regulation
62.10.5 and .6.)
3.16.5 Vacuum breakers provided to prevent the
water loops being emptied should vent to a position on the open deck.