1 Where the piping arrangements for dewatering
closed dry spaces are connected to the piping arrangements for the
drainage of water ballast tanks, two non-return valves should be provided
to prevent the ingress of water into dry spaces from those intended
for the carriage of water ballast. One of these non-return valves
should be fitted with a shut-off isolation arrangement. The non-return
valves should be located in readily accessible positions. The shut-off
isolation arrangement should be capable of being controlled from the
navigation bridge, the propulsion machinery control position or enclosed
space which is readily accessible from the navigation bridge or the
propulsion machinery control position without travelling exposed freeboard
or superstructure decks. In this context, a position which is accessible
via an under-deck passage, a pipe trunk or other similar means of
access should not be taken as being in the "readily accessible enclosed
space".
2 Under SOLAS regulation
XII/13.1:
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.1 the valve specified under SOLAS regulation II-1/12.5.1 should be
capable of being controlled from the navigation bridge, the propulsion
machinery control position or enclosed space which is readily accessible
from the navigation bridge or the propulsion machinery control position
without travelling exposed freeboard or superstructure decks. In this
context, a position which is accessible via an under-deck passage,
a pipe trunk or other similar means of access should not be taken
as being in the "readily accessible enclosed space";
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.2 the valve should not move from the demanded
position in the case of failure of the control system power or actuator
power;
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.3 positive indication should be provided at the
remote control station to show that the valve is fully open or closed;
and
-
.4 local hand-powered valve operation from above
the freeboard deck, as permitted under SOLAS regulation II-1/12.5.1, is required.
An acceptable alternative to such arrangement may be remotely operated
actuators as specified in SOLAS regulation
XII/13.1, on the condition that all of the provisions of regulation 13.1 are met.
3 The dewatering arrangements should be such that
any accumulated water can be drained directly by a pump or eductor.
4 The dewatering arrangements should be such that
when they are in operation, other systems essential for the safety
of the ship including fire-fighting and bilge systems remain available
and ready for immediate use. The systems for normal operation of electric
power supplies, propulsion and steering should not be affected by
the operation of the dewatering systems. It should also be possible
to immediately start fire pumps and have a readily available supply
of fire-fighting water and to be able to configure and use the bilge
system for any compartment when the dewatering system is in operation.
5 Bilge wells should be provided with gratings
or strainers that will prevent blockage of the dewatering system with
debris.
6 The enclosures of electrical equipment for the
dewatering system installed in any of the forward dry spaces should
provide protection to IPX8 standard as defined in publication IEC
60529 for a water head equal to the height of the space in which the
electrical equipment is installed for a time duration of at least
24 h.