Air pipes allow an enclosed space to 'breathe.' They prevent
over-or under-pressure by letting air in or out of the space when
liquid is pumped in or out, or when temperature changes cause air
or fluids to expand or contract. Cargo holds are ventilated by air
pipes passing through the weather deck, and these are fitted with
self-closing watertight covers (headers). This is a Load Line
requirement.
Sounding pipes are small-bore mild steel pipes used to measure
the quantity of fluid in a tank or a hold bilge. The pipe allows a
tape or sounding rod to pass through to the bottom of a tank or
hold. Deck sounding pipes pass through the weather deck and
are fitted with screw-down caps. Sounding pipes for engine
room double-bottom tanks are fitted with self-closing cocks.
Sounding pipe caps or cocks must be kept shut.
Sounding pipes are a potentially dangerous source of progressive
flooding. An engine room can be flooded through an open sounding
pipe if a ship's bottom is holed. A cargo hold can be flooded
through an open deck sounding pipe when water is washed on
deck in heavy weather. Holes in weather deck air pipes also cause
hold flooding during heavy weather.
Air and sounding pipes are normally constructed of mild steel.
Most of the time, these pipes do not come into contact with liquid,
either inside or outside. The size of an air pipe serving a tank is
determined by a comparison of its cross-section area with the pipe length to fill or empty the tank. This determination,
by the designer, is to avoid the risk of over- or under-pressure.
Air and sounding pipes that pass through other compartments
are a potential source of progressive flooding. It is difficult to
inspect air and sounding pipes located inside cargo spaces or
ballast tanks. However, the integrity of air pipes for ballast tanks
can be checked by overfilling the tanks. Pipes passing through a
dry cargo space must be inspected for damage caused by contact
with grabs, bulldozers, etc.
It is advisable to open and to inspect
air pipe headers on the exposed weather deck once every five
years following the first special survey. It is necessary because
corrosion on the inside of an air pipe header will not be noticeable
externally. Screw-down caps are fitted on the top of the sounding
pipes. These caps should never be mislaid or replaced with
wooden plugs. To extend the life of air pipe headers, they should
be galvanized. The self-closing cocks on engine room sounding
pipes should never be tied open.
Carrying out soundings of cargo hold bilges, fresh water and ballast tanks -Use of bilge high level alarms
Whether the vessel is in port or at sea, all spaces with a bilge sounding pipe (as per ship's drawings) should be sounded at least once a day except during heavy weather where Master finds it unsafe to access specific locations.
The Chief Officer and the Chief Engineer (for Engine room) shall designate crew to carry out
sounding of bilges and tanks.
The following standards to be complied: -
Bilge
(Hold, Engine Room, Cofferdam, Void space, Chain Locker,
Emergency Fire Pump Room, Bow Thruster Room, etc.)
When the Bilge High-Level Alarm activated (where equipped), take the space's soundings immediately, and keep monitoring.
Any abnormal soundings are to be investigated and reported to the office.
-
Fresh Water Tanks
Whether the vessel is in port or at sea, all freshwater tanks are to be measured and monitored for consumption at least a day.
Any abnormal findings are to be investigated and reported to the office.
-
Ballast Water Tanks
No matter whether the vessel is in port or at sea, sound at least a day from the sounding pipe or measure by the remote level gauge.
If remote level gauges are used for the daily soundings, these shall be periodically verified for accuracy by comparing manual soundings with gauge soundings.
Sounding pipes on exposed decks may not be sounded when unsafe to do so as in heavy weather.
Any abnormal soundings are to be investigated and reported to the office.
-
Record of soundings
Sounding Note of Bilge and Tanks:
The Chief Officer shall prepare the Record Book for 'Sounding of Bilge and Tanks' and shall have crew enter the result of soundings, check it every day, and affix his signature.
If sounding is not taken for any reason such as heavy weather, proper log entry must be made stating the reason in the Record Book.
Record of Engine Room Bilge:
The Chief Engineer shall have crew enter the result of soundings of engine room bilge into the M-zero Check List (or Sounding Note of Engine Room Bilge) check it every day, and affix his signature.
-
Inspection of bilge high level alarm
The Chief Officer shall test the operation of Bilge High-Level Alarm Systems in
Cargo Holds every three months and records the results.
The Chief Engineer shall test the operation of Engine Room Bilge High-Level Alarm System every month, and record the results.
Action in abnormal conditions
When the Chief Officer and Chief Engineer find the following abnormal conditions, he shall notify the Master, examine the cause and take measures immediately: -
Abnormal increase of bilge (Confirm whether Seawater or Freshwater)
-
Abnormal change of tank level
-
Existence of Oil in the Bilgewater or Ballast water
-
Malfunction of Bilge High Level Alarm System
Related Topics
Use of bilge oily water separator
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