Page 313 - Ship Construction.DJ Eyres 6Ed

Ch26-H8070.fm Page 302 Wednesday, October 18, 2006 7:01 AM
302 Ship Construction
storage type hot water heater fitted with heater coils, and then the heated
water is pumped to the outlet.
The sanitary system supplies sea water for flushing water closets, etc.,
and may be provided with a hydro-pneumatic pump in cargo vessels, but on
larger passenger ships where the demand is heavier, a continuously operat-
ing power pump is required.
It is a statutory requirement that a fire main and deck wash system should
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be supplied. This has hose outlets on the various decks, and is supplied by
power driven pumps in the machinery spaces. Provision may be made for
washing down the anchor chain from a connection to the fire main.
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี

Air and Sounding Pipes

Air pipes are provided for all tanks to prevent air being trapped under
pressure in the tank when it is filled, or a vacuum being created when it is emp-
tied. The air pipes may be fitted at the opposite end of the tank to the filling
pipe and/or at the highest point of the tank. Each air pipe from a double
bottom tank, deep tanks which extend to the ship’s side, or any tank which may
be run up from the sea, is led up above the bulkhead deck. From oil fuel
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and cargo oil tanks, cofferdams, and all tanks which can be pumped up, the air
pipes are led to an open deck, in a position where no danger will result from
leaking oil or vapours. The heights above decks and closing arrangements
are covered by the Load Line Conditions of Assignment (see Chapter 31).
Sounding pipes are provided to all tanks, and compartments not readily
accessible, and are located so that soundings are taken in the vicinity of the
suctions, i.e. at the lowest point of the tank. Each sounding pipe is made
as straight as possible and is led above the bulkhead deck, except in some
machinery spaces where this might not be practicable. A minimum bore of
32 mm is in general required for sounding pipes; but where they pass
through refrigeration spaces, to allow for icing, a minimum bore of 65 mm
is required where the temperature is at 0 °C or less. Underneath the sound-
ing pipe a striking plate is provided where the sounding rod drops in the
bilge well, etc. Sometimes a slotted sounding pipe is fitted to indicate the
depth of liquid present, and the closed end must be substantial to allow for
the sounding rod striking it regularly. Various patent tank sounding devices
are available and can be fitted in lieu of sounding pipes, as long as they
satisfy the requirements of the classification society.

Sea Inlets

Where the piping system requires water to be drawn from the sea, for
example fire and washdeck, ballast and machinery cooling systems, the inlet