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Part D Service Notations
Chapter 7 Oil Tanker and FLS Tanker
Section 4 Machinery and Cargo Systems
3 Cargo pumping and piping systems
3.5 Arrangement of cargo
3.5.1 Pump room ventilationIn addition to the provisions of Ch 7, Sec 2, [2.3.3],
the ventilation of the cargo pump room is to comply with the following
- Cargo pump rooms are to be mechanically ventilated and
discharges from exhaust fans are to be led to a safe place on the
open deck. The ventilation of these rooms is to have sufficient
capacity to minimize the possibility of accumulation of flammable
vapours. The number of changes of air is to be at least 20 per hour,
based upon the gross volume of the space. The air ducts are to be arranged
so that all of the space is effectively ventilated. The ventilation
is to be of the suction type using fans of the non-sparking type.
- The ventilation ducts are to be so arranged that their suction
is just above the transverse floor plates or bottom longitudinals
in the vicinity of bilges.
- An emergency intake located about 2,20 m above the pump
room lower grating is to be provided. It is to be fitted with a
damper capable of being opened or closed from the exposed main deck
and lower grating level.
Ventilation through the emergency intake is to be effective
when the lower intakes are sealed off due to flooding in the bilges.
- The foregoing exhaust system is in association with open
grating floor plates to allow the free flow of air.
- Arrangements involving a specific ratio of areas of
upper emergency and lower main ventilator openings, which can be
shown to result in at least the required 20 air changes per hour
through the lower inlets, can be adopted without the use of dampers.
When the lower access inlets are closed then at least 15 air changes
per hour should be obtained through the upper inlets.
3.5.2 Measures to prevent
explosionsThe provisions of [3.5.2] do not apply to ships
having one of the following service notations:
except where the cargo is carried at a temperature above 15°C
from the flash point.
- oil tanker, flash point > 60°C
- oil tanker, asphalt carrier
- FLS tanker, flash point > 60°C,
- Where cargo pumps, ballast pumps and stripping pumps
are driven by a machine which is located outside the cargo pump
room, the following arrangements are to be made:
- drive shafts are to be fitted with flexible couplings
or other means suitable to compensate for any misalignment
- the shaft bulkhead or deck penetration is to be fitted with
a gas-tight gland of a type approved by the Society. The gland is
to be efficiently lubricated from outside the pump room and so designed
as to prevent overheating. The seal parts of the gland are to be
of material that cannot initiate sparks.
- Temperature sensing devices are to be fitted for bulkhead
shaft glands, bearings and pump casings.
- To discourage personnel from entering the cargo pump room
when the ventilation is not in operation, the lighting in the cargo
pump room is to be interlocked with ventilation such that ventilation
is to be in operation to energise the lighting.
Failure of the ventilation system is not to cause the lighting
to go out. Emergency lighting, if fitted, is not to be interlocked.
- A system for continuously monitoring the concentration of
hydrocarbon gases is to be fitted. Sampling points or detector heads
are to be located in suitable positions in order that potentially
dangerous leakages are readily detected. Sequential sampling is
acceptable as long as it is dedicated for the pump room only, including
exhaust ducts, and the sampling time is reasonably short. Suitable positions
may be the exhaust ventilation duct and lower parts of the pump
room above floor plates. The system is to raise an alarm if the
concentration of hydrocarbon gases exceeds 10 per cent of the lower
flammable limit (LFL). The alarm signals (visual and audible) are
to be provided in the cargo controlroom and on the navigation bridge.
- High liquid level in the bilges is to activate an audible and
visual alarm in the cargo control room and on the navigation bridge.