Environmental Engineering Reference
In-Depth Information
Fig. 12
Slightly bended sounding pipe on a car carrier which would not enable all sampling
equipment described above to be lowered to the tank bottom
The sounding pipe requirements (rules) of some members of the International
Association of Classifi cation Societies, London (IACS) regarding the construction
of the pipes have been analysed. The minimum sounding pipe requirements include
(David and Perkovi
č
2004
):
• all ballast water tanks should have sounding pipes, which need to be as straight
as practicable (see Fig.
12
),
•
sounding pipes should not be less than 32 mm of internal diameter, and
•
they must always be accessible.
Certain technical limitations were also identifi ed when analysing the sampling
accessibility of ballast water through sounding pipes. These are the pipe diameter
and the distance of the water depth level inside the tank from the sampling point
on deck. David and Perkovi
(
2004
) further noticed that most sounding pipes have
a welding under their cover, which narrows the access into the pipe by a reduced
pipe diameter. Due to the limited sounding pipe diameter sampling equipment
such as plankton nets, buckets etc. cannot be used for sampling. Further, suction
pumps are practically excluded from an application if the pumping head (distance
from the sampling point to the water level inside the tank) is more than 9 m.
Therefore, sounding pipe sampling at greater depths to, e.g., double bottom tanks
(some ships may only have double bottom tanks, or ballast water may just be car-
ried in double bottom tanks) will require a well pump of smaller diameter to be
lowered down the pipe.
č
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