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MERCHANT SHIPPING (PREVENTION OF OIL POLLUTION) REGULATIONS - SCHEDULE 7
SPECIFICATIONS FOR THE DESIGN, OPERATION AND CONTROL OF CRUDE OIL WASHING SYSTEMS
(Past version on 30/06/1997).
[regulation 21(2) & (4)]
Any reference in this Schedule to a Resolution means a reference to a
Resolution of that number published by the Organisation.
INDEX OF SECTIONS
1. Purpose
2. Application
3. General provisions 3.1 Definition 3.2 Initial survey
4. Design criteria 4.1 Piping 4.2 Tank washing machines 4.3 Pumps 4.4
Stripping system 4.5 Ballast lines
5. Qualification of personnel
6. Operation 6.1 Tankage to be crude oil washed 6.2 Drainage and discharge
ashore of cargo lines 6.3 Filling of departure ballast tanks 6.4 Crude oil
washing at sea 6.5 Discharge of oily water effluents on ballast voyage 6.6 Use
and control of inert gas 6.7 Precautions against electrostatic generation 6.8
Vapour emission
7. Operations and Equipment Manual
APPENDIX I- Modifications for applying the Specifications to new
crude oil tankers of 20000 tons deadweight and above
APPENDIX II- Training for persons intended to assume overall charge of
crude oil washing
1. PURPOSE
The purpose of these Specifications is to provide specific design criteria,
operational requirements and control and enforcement procedures for the
crude oil washing of cargo tanks of crude oil carriers as described in
section 2.
2. APPLICATION
2.1 These Specifications apply to-
(a) Existing crude oil tankers of 40000 tons deadweight and above in
accordance with regulation 18(8) of these Regulations; and
(b) New crude oil tankers of 20000 tons deadweight and above in accordance
with regulation 18(6) of these Regulations with the modifications
specified in Appendix I. Compliance of these ships with these
Specifications shall be shown on the IOPP or HKOPP Certificate.
2.2 If a crude oil that is not suitable for crude oil washing is intended to
be carried as cargo in a ship that is provided with only a crude oil washing
system, that ship must comply with segregated ballast tank requirements in
accordance with regulation 18(7) or dedicated clean ballast tank requirements
in accordance with regulation 18(9) of these Regulations.
3. GENERAL PROVISIONS
3.1 Definitions For the purpose of these Specifications:
3.1.1 "Arrival ballast" (到港壓載) means clean ballast as defined in
regulation 1(2) of these Regulations.
3.1.2 "Departure ballast" (離港壓載) means ballast other than arrival
ballast.
3.1.3 "Water rinse" (水洗) means the water washing process carried out in
connection with tank cleaning after crude oil washing and is not intended to
be construed as limiting the amount of water needed in the process.
3.2 Initial survey The initial survey referred to in regulation 4 of these
Regulations shall include a complete inspection of the crude oil washing
equipment and arrangements and shall include, except for the cases specified
in paragraph 4.2.11, an examination of the tanks after they have been crude
oil washed and the additional tests as specified in paragraph 4.2.10 to ensure
that the washing system efficiency is in accordance with these Specifications.
4. DESIGN CRITERIA
4.1 Piping
4.1.1 The crude oil washing pipes and all valves incorporated in the supply
piping system shall be of steel or other equivalent material and shall be of
adequate strength having regard to the pressure to which they may be
subjected, and shall be properly jointed and supported.
4.1.2 The crude oil washing system shall consist of permanent pipework and
shall be independent of the fire mains and of any system other than that for
tank washing, except that sections of the ship's cargo system may be
incorporated into the crude oil washing system provided that they meet the
requirements applicable to crude oil pipework. Notwithstanding the above
requirements, in combination carriers the arrangement may allow-
(a) the removal of the equipment, if necessary, when carrying cargoes
other than crude oil, provided that, when reinstated, the system is as
originally fitted and tested for oil tightness;
(b) the use of flexible hose pipes to connect the crude oil washing system
to tank washing machines if it is necessary to locate these machines
in a cargo tank hatch cover. Such flexible hose pipes shall be
provided with flanged connections and be manufactured and tested in
accordance with standards acceptable to the Director, and be
consistent with the duties which they are required to perform. The
length of these hoses shall be no greater than necessary to connect
the tank washing machines to an adjacent point just outside the hatch
coaming. These hoses shall be removed to suitably prepared and
protected stowage when not in use and be pressure tested by an
authority acceptable to the Director at intervals of not more than two
and a half years. (37 of 1990 s. 12)
4.1.3 Provision shall be made to prevent overpressure in the tank washing
supply piping. Any relief device fitted to prevent overpressure shall
discharge into the suction side of the supply pump. Alternative methods to the
satisfaction of the Director may be accepted provided an equivalent degree of
safety and environmental protection is provided.
4.1.4 Where hydrant valves are fitted for water washing purposes on tank
washing lines, all such valves shall be of adequate strength and provision
shall be made for such connections to be blanked off by blank flanges when the
washing lines may contain crude oil. Alternatively, hydrant valves shall be
isolated from the crude oil washing system by spade blanks.
4.1.5 All connections for pressure gauges or other instrumentation shall be
provided with isolating valves adjacent to the lines unless the fitting is of
the sealed type.
4.1.6 No part of the crude oil washing system shall enter the machinery
spaces. Where the tank washing system is fitted with a steam heater for use
when water washing, the heater must be effectively isolated during crude oil
washing by double shut-off valves or by clearly identifiable blanks.
4.1.7 Where combined crude oil-water washing supply piping is provided the
piping shall be so designed that it can be drained so far as is practicable of
crude oil, before water washing is commenced, into spaces designated in the
Operations and Equipment Manual. These spaces may be the slop tank or other
cargo spaces.
4.1.8 The piping system shall be of such diameter that the greatest number of
tank cleaning machines required, as specified in the Operations and Equipment
Manual, can be operated simultaneously at the designed pressure and
throughput. The arrangement of the piping shall be such that the required
number of tank cleaning machines to each cargo compartment specified in the
Operations and Equipment Manual can be operated simultaneously.
4.1.9 The piping system shall be tested to one and one half times the working
pressure after it has been installed on the ship.
4.1.10 The crude oil washing supply piping shall be anchored
(firmly attached) to the ship's structure at appropriate locations, and means
shall be provided to permit freedom of movement elsewhere to accommodate
thermal expansion and flexing of the ship. The anchoring shall be such that
any hydraulic shock can be absorbed without undue movement of the supply
piping. These anchors should normally be situated at the ends furthest from
the entry of the crude oil supply to the supply piping. If tank washing
machines are used to anchor the ends of branch pipes then special arrangements
shall be made to anchor these sections when the machines are removed for any
reason.
4.2 Tank washing machines
4.2.1 The tank washing machines for crude oil washing shall be permanently
mounted and shall be of an approved design.
4.2.2 The performance characteristic of a tank washing machine is governed by
nozzle diameter, working pressure and the movement pattern and timing. Each
tank cleaning machine fitted shall have a characteristic such that the
sections of the cargo tank covered by that machine will be effectively cleaned
within the time specified in the Operations and Equipment Manual.
4.2.3 Tank washing machines shall be mounted in each cargo tank and the method
of support shall be to the satisfaction of the Certifying Authority. Where
the tank washing machines are positioned well below the deck level to cater
for protuberances in the tank, consideration may need to be given to
additional support for the machine and its supply piping.
4.2.4 Each machine shall be capable of being isolated by means of stop valves
in the supply line. If a deck mounted tank washing machine is removed for any
reason, provision shall be made to blank off the oil supply line to the
machine for the period the machine is removed. Similarly, provision shall be
made to close the tank opening with a plate or equivalent means.
4.2.5 Where the drive units for the tank cleaning machines are not integral
with the tank cleaning machine, sufficient drive units shall be provided to
ensure that no drive unit need be moved more than twice from its original
position during cargo discharge to accomplish the washing programme as
specified in the Operations and Equipment Manual.
4.2.6 The number and location of the tank washing machines shall be to the
satisfaction of the Certifying Authority.
4.2.7 The location of the machines is dependent upon the characteristics
detailed in paragraph 4.2.2 and upon the configuration of the internal
structure of the tank.
4.2.8 The number and location of the machines in each cargo tank shall be such
that all horizontal and vertical areas are washed by direct impingement or
effectively by deflection or splashing of the impinging jet. In assessing an
acceptable degree of jet deflection and splashing, particular attention shall
be paid to the washing of upward facing horizontal areas and the following
parameters shall be used-
(a) For horizontal areas of a tank bottom and the upper surfaces of a
tank's stringers and other large primary structural members, the total
areas shielded from direct impingement by deck or bottom transverses,
main girders, stringers or similar large primary structural members
shall not exceed 10 per cent of the total horizontal area of tank
bottom, the upper surface of stringers, and other large primary
structural members.
(b) For vertical areas of the sides of a tank, the total area of the
tank's sides shielded from direct impingement by deck or bottom
transverses, main girders, stringers or similar large primary
structural members shall not exceed 15 per cent of the total area of
the tank's sides.
(c) For existing crude oil tankers, the Certifying Authority may permit
the percentages required in (a) and (b) above to be exceeded for tanks
having complicated internal structural members provided that the
percentages calculated over all the cargo tanks do not exceed 10 per
cent for horizontal areas and 15 per cent for vertical areas. In some
installations it may be necessary to consider the fitting of more than
one type of tank washing machine in order to effect adequate coverage.
4.2.9 At the design stage the following minimum procedures shall be used to
determine the area of the tank surface covered by direct impingement-
(a) Using suitable structural plans, lines are set out from the tips of
each machine to those parts of the tank within the range of the jets.
(b) Where the configuration of the tanks is considered by the
Certifying Authority to be complicated, a pinpoint of light simulating
the tip of the tank washing machine in a scale model of the tank shall
be used.
4.2.10 (a) To confirm the cleanliness of the tank and to verify the design in
respect of the number and location of the tank washing machines, a visual
inspection shall be made by entry to the tanks after a crude oil wash but
prior to any water rinse which may be specified in the Operations and
Equipment Manual. The bottom of the tank to be inspected may, however, be
flushed with water and stripped in order to remove any heel of crude oil
remaining on the tank bottom before gas freeing for entry. This inspection
shall ensure that the tank is essentially free of oil clingage and deposits.
If the flushing procedure is adopted, a similar but unflushed tank must be
used for the test specified in (b) below.
(b) To verify the effectiveness of the stripping and drainage
arrangements, a measurement shall be made of the amount of oil
floating on top of the departure ballast. The ratio of the volume of
oil on top of the total departure ballast water to the volume of tanks
that contain this water shall not exceed 0.00085. This test shall be
carried out after crude oil washing and stripping in a tank similar
in all relevant respects to the tank examined in accordance with
sub-paragraph (a) above, which has not been subjected to a water rinse
or to the intervening water flushing permitted by sub-paragraph (a).
(c) To verify the design, installation and operation of the system, the
arrival ballast, after a typical ballast voyage before which the
arrival ballast tanks have been crude oil washed and during which the
tanks have been water rinsed in accordance with the programme set out
in the Operations and Equipment Manual, shall be totally discharged to
the loading port harbour through an approved oil monitoring system and
the oil content of the effluent in this test shall not exceed 15 ppm.
4.2.11 Where the Certifying Authority is satisfied that ships are similar in
all relevant respects, the requirements of paragraph 4.2.10 need only be
applied to one such ship. Furthermore, where a ship has a series of tanks that
are similar in all relevant respects then, for that series of tanks, the
requirements of paragraph 4.2.10(a) need be applied to only one tank of that
series.
4.2.12 The design of the deck mounted tank washing machines shall be such that
means are provided external to the cargo tanks which, when crude oil washing
is in progress, would indicate the rotation and arc of the movement of the
machine. Where the deck mounted machine is of the non-programmable, dual
nozzle type, alternative methods to the satisfaction of the
Certifying Authority may be accepted, provided an equivalent degree of
verification is attained.
4.2.13 Where submerged machines are required, they shall be non-programmable
and, in order to comply with the requirements of paragraph 4.2.8, it shall be
possible to verify their rotation by one of the following methods-
(a) by indicators external to the tank;
(b) by checking the characteristic sound pattern of the machine, in which
case the operation of the machine shall be verified towards the end of
each wash cycle. Where two or more submerged machines are installed on
the same supply line, valves shall be provided and arranged so that
operation of each machine can be verified independently of the other
machines on the same supply line;
(c) by gas freeing the tank and checking the operation of the machine with
water during ballast voyages. In this case the check shall take place
after a maximum of six usages of the machine but the interval between
checks shall not exceed 12 months. Each verification shall be recorded
in the Oil Record Book, Part II-Cargo/Ballast Operations. The method
of verification shall be stated in the Operations and Equipment
Manual.
4.3 Pumps
4.3.1 The pumps supplying crude oil to the tank cleaning machines shall be
either the cargo pumps or pumps specifically provided for the purpose.
4.3.2 The capacity of the pumps shall be sufficient to provide the necessary
throughput at the required pressure for the maximum number of tank cleaning
machines required to be operated simultaneously as specified in the Operations
and Equipment Manual. In addition the pumps shall, if an eductor system is
fitted for tank stripping, be capable of supplying the eductor driving fluid
to meet the requirements of paragraph 4.4.2.
4.3.3 The capacity of the pumps shall be such that the requirements of
paragraph 4.3.2 can be met with any one pump inoperative. The pumping and
piping arrangements shall be such that the crude oil washing system can be
effectively operated with any one pump out of use.
4.3.4 The carriage of more than one grade of cargo shall not prevent crude oil
washing of tanks.
4.3.5 To permit crude oil washing to be effectively carried out where the back
pressure presented by the shore terminal is below the pressure required for
crude oil washing, provision shall be made such that an adequate pressure to
the washing machines can be maintained in accordance with paragraph 4.3.2.
This requirement shall be met with any one cargo pump out of action. The
minimum supply pressure required for crude oil washing shall be specified in
the Operations and Equipment Manual. Should this minimum supply pressure not
be obtainable, crude oil washing operations shall not be carried out.
4.4 Stripping system
4.4.1 The design of the system for stripping crude oil from the bottom of
every cargo tank shall be to the satisfaction of the Certifying Authority.
4.4.2 The design and capacity of the tank stripping system shall be such that
the bottom of the tank being cleaned is kept free of accumulations of oil and
sediment towards completion of the tank washing process.
4.4.3 The stripping system shall be capable of removing oil at a rate of 1.25
times the total throughput of all the tank cleaning machines to be operated
simultaneously when washing the bottom of the cargo tanks as described in the
ship's Operations and Equipment Manual.
4.4.4 Means such as level gauges, hand dipping and stripping system
performance gauges as referred to in paragraph 4.4.8 shall be provided for
checking that the bottom of every cargo tank is dry after crude oil washing.
Suitable arrangements for hand dipping must be provided at the aftermost
portion of a cargo tank and in three other suitable locations unless other
means approved by the Certifying Authority are fitted for efficiently
ascertaining that the bottom of every cargo tank is dry. For the purpose of
this paragraph, the cargo tank bottom shall be considered "dry" if there is no
more than a small quantity of oil near the stripping suction with no
accumulation of oil elsewhere in the tank.
4.4.5 Means shall be provided to drain all cargo pumps and lines at the
completion of cargo discharge, where necessary, by connection to a stripping
device. The line and pump draining shall be capable of being discharged both
to a cargo tank and ashore. For discharge ashore a special small diameter line
shall be provided for that purpose and connected outboard of the ship's
manifold valve. For new oil tankers or existing oil tankers not already
fitted with such a line the cross-sectional area of this line shall not exceed
10 per cent of that of a main cargo discharge line. Where such a line is
already fitted on an existing tanker, a cross-sectional area of not more than
25 per cent of that of a main cargo discharge line may be accepted.
4.4.6 The means for stripping oil from the cargo tanks shall be by positive
displacement pump, self-priming centrifugal pump or eductor or other methods
to the satisfaction of the Certifying Authority. Where a stripping line is
connected to a number of tanks, means shall be provided for isolating each
tank not being stripped at that particular time.
4.4.7 The carriage of more than one grade of cargo shall not prevent crude oil
washing of tanks.
4.4.8 Equipment shall be provided for monitoring the efficiency of the
stripping system. All such equipment shall have remote read out facilities in
the cargo control room or in some other safe and convenient place easily
accessible to the officer in charge of cargo and crude oil washing operations.
Where a stripping pump is provided, the monitoring equipment shall include
either a flow indicator, or a stroke counter or revolution counter as
appropriate, and pressure gauges at the inlet and discharge connections of the
pump or equivalent. Where eductors are provided the monitoring equipment shall
include pressure gauges at the driving fluid intake and at the discharge and a
pressure/vacuum gauge at the suction intake.
4.4.9 The internal structure of the tank shall be such that drainage of oil to
the tank suctions of the stripping system is adequate to meet the requirements
of paragraphs 4.4.2 and 4.4.4. Care shall be taken that both longitudinal and
transverse drainage are satisfactory and shall be verified during the
inspection required by paragraphs 3.2 and 4.2.10.
4.4.10 The trim conditions for crude oil washing given in the Operations and
Equipment Manual shall be adhered to. In general, trim by the stern is only
important during the final stages of tank discharge and shall be the maximum
possible compatible with operational constraints but in no case less than that
recorded during the crude oil washing prior to the inspection required by
paragraphs 3.2 and 4.2.10.
4.5 Ballast lines
4.5.1 Where a separate ballast water system for ballasting cargo tanks is not
provided, the arrangement shall be such that the cargo pump, manifolds and
pipes used for ballasting can be safely and effectively drained of oil before
ballasting.
5. QUALIFICATION OF PERSONNEL
5.1 The training requirements of ships' personnel engaged in the crude oil
washing of tankers shall be to the satisfaction of the Director.
5.2 Where a person such as the master, the chief officer or the cargo control
officer assumes overall charge of a crude oil wash he shall-
(a) have had at least one year's experience on oil tankers where his
duties have included the discharge of cargo and associated crude
washing. Where his duties have not included crude oil washing
operations, he shall have completed a training programme in crude oil
washing in accordance with Appendix II to these Specifications and
satisfactory to the Director;
(b) have participated at least twice in crude oil wash programmes, one of
which shall have been in the particular ship for which he is required
to undertake the responsibility of cargo discharge or on a ship that
is similar in all relevant respects; and
(c) be fully knowledgeable of the contents of the Operations and Equipment
Manual.
5.3 Where other nominated persons are intended to have particular
responsibilities as defined in the Operations and Equipment Manual they shall
have at least 6 months experience on oil tankers where, in the course of their
duties, they shall have been involved in the cargo discharge operation. In
addition, they shall have been instructed in the matters specified in Appendix
II to these Specifications, in the crude oil washing operation in the
particular ship for which they are required to undertake this responsibility
and be fully knowledgeable of the contents of the Operations and Equipment
Manual.
6. OPERATION
6.1 Tankage to be crude oil washed
Before departure on a ballast voyage, after the complete discharge of cargo,
sufficient tanks shall have been crude oil washed in accordance with the
procedures specified in the Operations and Equipment Manual to ensure that-
(a) as a minimum, sufficient tanks have been washed to permit compliance
with the draught and trim requirements of regulation 18(2)(a),
(b) and (c) of these Regulations during all phases of the ballast voyage;
and
(b) account is taken of the ship's trading pattern and the expected
weather conditions so that additional ballast water is not put into
tanks which have not been crude oil washed. In addition to the tanks
referred to in (a) above, approximately one quarter of all remaining
tanks shall be crude oil washed for sludge control on a rotational
basis, but these additional tanks may include the tanks referred to in
(b) above. However, for sludge control purposes, no tank need be
crude oil washed more than once in every four months. Crude oil
washing shall not be conducted between the final discharge and loading
ports; that is to say, no crude oil washing shall be undertaken during
the ballast voyage. Ballast water shall not be put into tanks that
have not been crude oil washed. Water that is put into a tank which
has been crude oil washed but not water rinsed shall be regarded as
dirty ballast.
6.2 Drainage and discharge ashore of cargo lines At the end of cargo discharge
all cargo mains and stripping lines shall be drained and stripped and the
drainings and strippings discharged ashore via the special diameter line
required by paragraph 4.4.5. In addition all cargo tanks shall be stripped
before the ship leaves its final port of discharge.
6.3 Filling of departure ballast tanks Care shall be taken at the completion
of crude oil washing of any departure ballast tanks to strip the tank as
completely as possible. Where departure ballast is filled through cargo lines
and pumps, these must be drained and stripped of oil using the means required
by paragraph 4.4.5 before ballast is loaded.
6.4 Crude oil washing at sea All crude oil washing must be completed before
the ship leaves its final port of discharge. Where any tank is crude oil
washed while the ship is at sea between multiple discharge ports, the tank
shall be left empty and available for inspection at the next discharge port
before commencing the next ballast voyage. This inspection may consist of
multiple sounding/dipping of the bottom of the tank when the tank is empty.
Departure ballast tanks shall be ballasted prior to departure from port so
that examination of the surface of the ballast water can be made in accordance
with the provisions of paragraph 4.2.10(b).
6.5 Discharge of oily water effluents on ballast voyage The discharge of
departure ballast and any other water effluent discharged during the ballast
voyage shall comply with the requirements of regulation 13 of these
Regulations.
6.6 Use and control of inert gas On ships to which these Specifications apply,
no tank shall be crude oil washed unless the inert gas system required by the
Merchant Shipping (Safety) (Fire Protection) (Ships Built Before 25 May 1980)
Regulations ( Cap 369 sub. leg.), Merchant Shipping (Safety) (Fire Appliances)
(Ships Built On or After 25 May 1980 but Before 1 September 1984) Regulations
( Cap 369 sub. leg.), or Merchant Shipping (Safety) (Fire Protection) (Ships
Built On or After 1 September 1984) Regulations ( Cap 369 sub. leg.), as
appropriate, is in proper operation. Before each tank is crude oil washed,
the oxygen level shall be determined at a point 1 metre from the deck and at
the middle region of the ullage space and neither of these determinations
shall exceed 8 per cent by volume. Where tanks have complete or partial wash
bulkheads, the determinations shall be taken from similar levels in each
section of the tank. The oxygen level of the inert gas being delivered during
the washing process shall be continuously monitored. If during crude oil
washing- (37 of 1990 s. 12; 64 of 1999 s. 3)
(a) the oxygen level of the inert gas being delivered exceeds 8 per cent
by volume; or
(b) the pressure of the atmosphere at the tanks is no longer positive;
then the washing shall be stopped until satisfactory conditions are
restored.
6.7 Precautions against electrostatic generation To avoid excessive
electrostatic generation in the washing process due to the presence of water
in the crude oil washing fluid, the contents of any tank to be used as a
source of crude oil washing fluid must first be discharged by at least 1 metre
before being so used. Any tank used as a slop tank on the previous ballast
voyage shall be completely discharged and refilled with dry crude oil if that
tank is to be used as a source of washing fluid.
6.8 Vapour emission On ships to which these specifications apply there shall
be means to avoid vapour emission during the filling of departure ballast
wherever local conditions require it. The method of preventing the emission of
hydrocarbon vapour into the atmosphere shall be-
(a) by the use of permanent ballast tanks wherever these are sufficient to
provide the minimum departure draught; or
(b) by containment of vapour in empty cargo tanks by simultaneous
ballasting and cargo discharge. Alternative methods to the
satisfaction of the Director may be accepted provided an equivalent
degree of environmental protection is provided.
7. OPERATIONS AND EQUIPMENT MANUAL The Operations and Equipment Manual shall
be to the satisfaction of the Certifying Authority and shall contain the
following information and operational instructions-
(a) The complete text of the Specifications for the Design, Operation and
Control of Crude Oil Washing Systems as set out in this Schedule.
(b) A line drawing of the crude oil washing system showing the respective
position of pumps, lines and washing machines which relate to the
crude oil washing system.
(c) A description of the system and a list of procedures for checking that
equipment is working properly during crude oil washing operations.
This shall include a list of the system and equipment parameters to be
monitored, such as line pressure, oxygen level, machine revolutions,
duration of cycles, etc. The established values for these parameters
shall be included. The results of the tests carried out in accordance
with paragraph 4.2.10 and the values of all parameters monitored
during such tests shall also be included.
(d) Details of the requirements of section 6 ("Operation") of this
Schedule, together with advice and instructions, where appropriate, on
meeting these requirements, such as-
(i) Recommended methods and programmes of crude oil washing in
order to accord with all foreseeable circumstances of cargo
discharge restraints and to obtain maximum trim during the
completion of washing and draining of each tank.
(ii) The procedure on ships to avoid vapour emission in accordance
with paragraph 6.8.
(iii) The method of draining tanks which shall include information on
optimum trim conditions as required by paragraph 4.4.10.
(iv) The method of draining cargo pumps, cargo lines, crude oil
washing lines and stripping lines, and spaces into which they
may be drained, together with the final discharge ashore via
the small discharge line on completion of discharge.
(v) Typical washing programmes under various conditions of loading,
specifying-
(1) the tanks to be washed in accordance with paragraph 6.1;
(2) the method for washing each tank, that is single or multi-stage;
(3) the number of tank washing machines to be used simultaneously;
(4) the duration of the crude oil wash and water rinse where the latter is
appropriate;
(5) the volume of water used for water rinse, which shall be at least equal to
that used in the water rinse prior to the inspection required by paragraphs
3.2 and 4.2.10; and
(6) the preferred order in which the tanks are to be washed.
(vi) The procedure for draining and stripping, where appropriate,
cargo lines and pumps before being used for the loading of
departure ballast.
(vii) The procedure for water washing lines before discharge of
departure ballast and the loading and final discharge of
arrival ballast.
(viii) The procedure for verifying by sound patterns that bottom
mounted machines are operating shall be carried out towards the
end of the wash cycle for each tank. When carrying out such
verification all other machines shall be shut down if
necessary.
(ix) Precise details of the procedure to ensure compliance with
regulation 13 of these Regulations in the discharge of
departure ballast, the water flushing of lines and the
decanting of the slop tanks at sea.
(e) The dangers of leakage from the crude oil washing system and the
precautions necessary to prevent leakage and the action to be taken in
the event of a leakage. Guidance shall be given on how the crude oil
washing system is to be operationally tested for leakage before each
discharge.
(f) The method of preventing the entry of oil to the engine room through
steam heaters as required by paragraph 4.1.6.
(g) The personnel required at all times to conduct the dual operation of
discharging cargo and crude oil washing. The numbers of such personnel
shall include-
(i) the person meeting the requirements of paragraph 5.2 who will
have overall control of the crude oil washing process;
(ii) those persons meeting the requirements of paragraph 5.3 who
will be expected to undertake the actual operation; and
(iii) at least one person on deck at all times during washing to keep
watch for leaks and malfunctioning of equipment, to test the
oxygen content of tanks before washing, to check tank
atmosphere pressure, to sound tank bottoms if required, to lift
ullage floats if necessary and to change drive units when this
is necessary. The duties of such persons are not necessarily
mutually exclusive.
(h) An effective means of communication between the watchkeeper on deck
and the cargo control position so that in the event of a leak in or
malfunctioning of the crude oil washing system the washing may be
stopped as soon as possible.
(i) The typical procedures for ballasting.
(j) A pre-crude oil wash operational check list for the use of the crew at
each discharge, which shall include the checking and calibration of
all instruments.
(k) The recommended intervals for on board inspection and maintenance of
crude oil washing equipment in addition to statutory surveys.
Reference should be made to technical manuals supplied by the
manufacturers of the equipment.
(l) A list of crude oil unsuitable for the crude oil washing process and
their origin.
____________
APPENDIX I
MODIFICATIONS FOR APPLYING THE SPECIFICATIONS TO NEW CRUDE OIL TANKERS OF 20
000 TONS DEADWEIGHT AND ABOVE
Paragraph number Modifications
---------------------------------------------------------------------------
--------------------------------------
4.2.5 This paragraph is not applicable.
4.2.10 Sub-paragraph (c) is not applicable.
6.1 Replace by the following- "6.1 Tankage to be crude oil washed 6.1.1 Before
departure on a ballast voyage-
(a) approximately one quarter of the cargo tanks shall be crude oil washed
for sludge control purposes on a rotational basis and in accordance
with the procedures specified in the Operations and Equipment Manual.
However, for these purposes, no tank need be crude oil washed more
than once in every four months; and
(b) if it is considered that additional ballast in a cargo tank or tanks
may be required during the ballast voyage under the conditions and
provisions specified in regulation 18(3) of these Regulations, the
tank or tanks which may be used for this ballast shall be crude oil
washed in accordance with the procedures specified in the Operations
and Equipment Manual. 6.1.2 Ballast water shall not be put into cargo
tanks that have not been crude oil washed. Water that is put into a
tank which has been crude oil washed but not water rinsed shall be
regarded as dirty ballast. 6.1.3 Crude oil washing shall not be
conducted between the final discharge and loading ports; that is to
say, no crude oil washing shall be undertaken during the ballast
voyage."
6.3 Replace by the following- "6.3 Ballasting of cargo tanks Care shall be
taken at the completion of crude oil washing of any cargo tank that might
contain ballast to strip the tank as completely as possible. Where this
ballast is filled through cargo lines and pumps, these must be drained and
stripped of oil using the means required by paragraph 4.4.5." 6.4 The last two
sentences are not applicable. 6.5 Replace by the following- "6.5 Discharge of
oily water effluents on ballast voyage The discharge of additional ballast
from cargo tanks and any other water effluent discharged during the ballast
voyage shall comply with the requirements of regulation 13 of these
Regulations."
6.8 This paragraph is not applicable. 7(d) Replace by the following- "7(d)
Details of the requirements of section 6 ("Operation") of this Schedule,
together with advice and instructions, where appropriate, on meeting these
requirements, such as-
(i) Recommended methods and programmes of crude oil washing in
order to accord with all foreseeable circumstances of cargo
discharge restraints and to obtain maximum trim during the
completion of washing and draining of each tank.
(ii) The method of draining tanks which shall include information on
optimum trim conditions as required by paragraph 4.4.10.
(iii) The method of draining cargo pumps, cargo lines, crude oil
washing lines and stripping lines, and spaces into which they
may be drained, together with the final discharge ashore via
the small discharge line on completion of discharge.
(iv) Typical washing programmes under various conditions of loading
specifying-
(1) the tanks to be washed in accordance with paragraph 6.1;
(2) the method for washing each tank, that is single or multi-stage;
(3) the number of tank washing machines to be used simultaneously;
(4) the duration of the crude oil wash and water rinse where the latter is
appropriate.
(v) The procedure for verifying by sound patterns that bottom
mounted machines are operating shall be carried out towards the
end of the wash cycle for each tank. When carrying out such
verification all other machines shall be shut down if
necessary."
___________
APPENDIX II
TRAINING FOR PERSONS INTENDED TO ASSUME OVERALL CHARGE OF CRUDE OIL WASHING
INTRODUCTION
Any required training shall be supervised instruction, conducted in a
shore-based facility or aboard a suitably equipped ship having training
facilities and instructors for this purpose, dealing with the principles
involved and the application of these principles to ship operation.
In drawing up a syllabus of training for approval by the Director, the revised
Specifications for the Design, Operation and Control of Crude Oil Washing
Systems of tankers shall be taken into account.
Such training shall include but not necessarily be limited to-
(a) An introduction to the principles of crude oil washing which shall
include: -the characteristics of crude oil as a washing fluid and its
contrast with water washing; -top washing; -bottom washing; -trim
requirements; -methods of bleeding off from the cargo discharge;
-maintenance of required washing fluid pressure; -washing at sea
between discharge ports; -recirculatory washing; -relative priorities
and requirements for the departure ballast tanks, arrival ballast
tanks and cargo only tanks.
(b) Equipment and design
(i) location of washing machines;
(ii) washing machines, deck mounted and submerged: -types;
-characteristics;
-features of construction; -operating parameters;
(iii) drive units;
(iv) washing fluid supply and distribution systems;
(v) stripping systems;
(vi) means of sounding tanks;
(vii) inert gas requirements.
(c) Generalized crude oil washing procedures
(i) traditional pipeline ship/free flow ship/partial free flow
ship;
(ii) single/multi parcel cargoes;
(iii) optimization of washing procedure in order to minimize extra
berth time;
(iv) ballasting for departure with various ship and pipeline
configurations;
(v) procedure for washing at sea between discharge ports.
(d) Associated procedure
(i) means for minimizing residues on board: -stripping of cargo
tanks; -draining and stripping of cargo lines; -final discharge
of cargo ashore;
(ii) water rinsing of arrival ballast tanks;
(iii) filling and ultimate discharge of arrival ballast;
(iv) discharge of departure ballast;
(v) build-up and decanting of residues in slop tank;
(vi) requirements of Regulation 13 of these Regulations;
(vii) avoidance of venting in port during ballasting operations.
(e) Safety
(i) inert gas procedure;
(ii) maintenance and monitoring of inert gas quality and pressure;
(iii) stopping of washing/discharge under abnormal inert gas
conditions;
(iv) electrostatic generation and the precautions required to avoid
it;
(v) pipework integrity;
(vi) avoidance of surge pressures;
(vii) spillage.
(f) Check lists
(i) before entering port;
(ii) before commencing crude oil washing;
(iii) after crude oil washing;
(iv) after sailing.
(g) Regulatory enforcement procedures
(i) Operations and Equipment Manual;
(ii) Oil Record Book;
(iii) sounding of tanks;
(iv) measurement of oil on surface of departure ballast.
(h) Maintenance of plant and equipment
(i) maintenance of equipment in accordance with manufacturers'
instructions;
(ii) additional maintenance items. "Arrival ballast" (到港壓載)
"Departure ballast" (離港壓載) "Water rinse" (水洗)
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