14.2.1 Substance and effluent tanks are to be protected from mechanical damage. This may be
achieved either by installation in spaces where there are no cargo or vehicle
movements and where no heavy lifting operations are expected; or by mechanical
protection, if installed in spaces where such operations may take place.
14.2.3 Where chemical substances are sensitive to variations in temperature, they are to be
maintained within their allowable maximum and minimum temperatures. Where necessary,
the probable temperature variations during operations and the thermal stress
considerations are to be stated. Where it is necessary either to heat or cool
chemical storage tanks, the arrangements are to maintain tanks within the specified
temperature range under the following conditions:
|
|
Heating systems
|
Cooling systems
|
| Seawater temperature
|
0°C
|
32°C
|
| Air temperature
|
5°C
|
45°C
|
14.2.4 Heating and cooling arrangements which utilise pipe coils or ducts for circulating a
heating or cooling medium within the chemical storage tank, or a heat exchanger
through which the chemical and a heating or cooling medium is circulated, are to use
heating or cooling media which is suitable for use with the specific chemical.
Consideration is to be given to the surface temperature of heating coils or ducts to
avoid dangerous reactions from localised overheating or overcooling of chemicals.
Heating or cooling systems are to be provided with valves to isolate the system and
to allow manual regulation of flow, along with a means for measuring the chemical
temperature.
14.2.5 Tank venting systems are to meet the requirements of Pt 15, Ch 2, 11 Air, overflow and sounding pipes, and are to minimise the possibility of chemical vapour
accumulating about the decks, entering accommodation, service and machinery spaces,
and control stations, and, in the case of flammable vapours, entering or collecting
in spaces or areas containing sources of ignition. Tank venting systems are to be
arranged to prevent entrance of water into the chemical tanks. The venting systems
shall be connected to the top of each chemical tank and, as far as is reasonably
practicable, are to be self-draining back to the chemical tanks under all normal
operational conditions of list and trim.
14.2.6 Chemical transfer and control arrangements are to be provided with a stop-valve
capable of being manually operated on each tank filling and discharge line, which
where practicable is to be attached directly to the tank plating. Additionally, a
stop valve at each chemical-hose loading connection. Where there is a possibility of
gravity discharge of the tank contents in the event of a pipe or valve failure then
discharge valve is to of the quick closing type.
14.2.7 Spillage and leakage from chemical tanks is to be contained. This may be achieved by
using containment bunds, or double skin tanks or by installing the tank in a
dedicated space. The arrangements are to consider the likely sources of spillage or
leakage and the anticipated volume released before the spillage or leakage can be
stopped.
14.2.8 Chemical tanks are to be arranged such that any residues and slops can be pumped out,
drained, or otherwise removed from the tank without exposing personnel to these
residues and slops.