5.24 PUMPROOM INSPECTIONS
An accurate log must be maintained of the pumproom operations, including
the starting and stopping time(s) of each pump and the reason for the
change. When each pump is started, it should be immediately inspected
for proper operations.
The inspection should include a visual check of the pump drive shaft
bulkhead seal, the driveshaft coupling, the forward and aft pump glands,
local readings of the pressure and RPM instruments (as compared to the
CCR readings).
If the pump is equipped with bearing, seal and/or casing temperature
probes, the local readings of these should be checked. If no temperature
sensors are fitted, the temperatures must be checked by hand. This can
only be done safely if the parts to be checked are safely guarded from
rotating parts. No part of the pump should be too hot to touch with
a bare hand: 60 °C (140 °F), unless the cargo is heated to a higher
temperature.
5.24.1 Pumproom ventilation
The pumproom ventilation should have been in operation continuously
since before arrival at the discharging berth. Continuous ventilation
is essential to maintaining a safe atmosphere at the bottom levels of
the pumproom.
All personnel assigned to conduct pumproom inspections have two principal
obligations:
• To advise the cargo watch officer before entering the pumproom to
make an inspection, when reaching the bottom of the pumproom and when
the inspection is complete.
• To verify that the pumproom ventilation is functioning properly before
descending below the top level of the pumproom.
The cargo officer should have a member of the deck watch stand by
at the top or some intermediate level of the pumproom to keep watch
over the person inspecting the lower level equipment. The crew member
keeping watch must have a portable radio and understand that his first
duty if the other person is overcome is to raise the alarm and then
ascend to the top of the pumproom to assist or become part of the rescue
team. He must not descend to the lower level to rescue his shipmate.
If the pumproom is under continuous ventilation there is adequate time
for a rescue to be organised (see section 2.15.8).
Pumproom rescue equipment must be immediately available in the pumproom
during cargo discharge.
5.24.2 Checking sea valves
Case study
Four days after Trieste harbour had suffered a major crude oil spill,
a 125,000 DWT tanker began discharging crude oil. At 1815, oil was discovered
along the vessel's port side. An investigation of the situation in the
pumproom disclosed that the port side sea chest was fitted with two butterfly
valves, both of which were apparently leaking. The outer valve was replaced.
Local authorities demanded a class inspection of the sea valves. The starboard
sea chest was also dismantled and checked. The vessel was arrested by
authorities to ensure clean up costs would be paid and owners were required
to post a bank guarantee of USD 250,000 to obtain its release. Clean up
costs totalled USD 207,000 when complete.
Case
analysis
This problem is largely caused by owner's selection of a valve specification
which was not appropriate for the critical function performed by the
pumproom sea chest. Having selected a less than optimal design, owner's
should have put in place a programme for regularly verifying the integrity
of the sea valves. (See section 2.18.1)
Apparently this was not done by owners, or by the master or chief officer
on their own initiative. The outcome of this management decision cost
considerably more than the installation of a more secure valve type!
A drain and sensor installation to prevent pollution
when pumproom valves leak.
One of the most common causes of harbour pollution by tankers is leakage
through sea valves. This is normally not a problem with SBT ships, but
is still a potential source of trouble for CBT vessels. Many vessels
are now fitted with butterfly valves on sea chests. Butterfly valves
offer a lower reliability for tightness than the previously used gate
valves. To minimise the potential for escape of oil leakage through
two butterfly valves, it is advisable to install a drain and tundish
arrangement near the outer valve, in a location where the drain valve
can be conveniently observed. An arrangement for such a drain system
is indicated in figure 5.24.2:
The drain should be left open at all times while discharging, Any leakage
through the upper valve will be detected as a flow from the drain valve.
The tundish and drain line will carry the drainage to the bilge. The
tundish line may be fitted with an liquid or oil detector to provide
remote indication of leakage. Any defects in the inner valve should
be repaired at the earliest opportunity.
5.24.3 Logbook entries
The pumping performance of the ship should be entered in detail in the
pumping log sheets, with main points entered in the deck logbook. Times
of starting and finishing individual cargo tanks should be included.
The time of pumproom inspections should be entered in each. If no problem
are noted, the entry should indicate that the pumproom was found 'in
apparent good order'. It is very important to log the times and reason
for any delay or stoppage, including the party or equipment responsible
for the stoppage and whether the stop was ordered by the ship or shore.
Within the limits of safe operations, the discharge should proceed as
requested by the receivers.
If any stoppage is caused by a failure of ship's equipment, full details
of the efforts to make necessary repairs should be set down, including
any obstructions or interferences to making repairs. It will be important
for owners to be able to demonstrate due diligence in seeking a remedy
to the delay and such demonstration cannot be made unless accurate records
are maintained.
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