Notes: For the purposes of the Unified Interpretations, the following abbreviations are
used:
MARPOL 73/78 |
The 1973 MARPOL Convention as modified by
the 1978 Protocol relating thereto |
Regulation |
Regulation in Annex I of MARPOL 73/78 |
IOPP Certificate |
International Oil Pollution Prevention Certificate |
SBT |
Segregated ballast tanks |
CBT |
Dedicated clean ballast tanks |
COW |
Crude oil washing system |
IGS |
Inert gas systems |
PL |
Protective location of segregated ballast tanks |
CAS |
Condition Assessment Scheme |
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1 Definitions |
Reg. 1.1 |
Definition of ‘‘oil’’ |
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1.1 (Animal and vegetable oils are found to fall under the category
of ‘‘noxious liquid substance’’, and therefore this interpretation has
been deleted (see Annex II, appendix II, of MARPOL 73/78).) |
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Treatment for oily rags |
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1.2 Oily rags, as defined in the Guidelines for the Implementation
of Annex V of MARPOL 73/78, should be treated in accordance
with Annex V and the procedures set out in the Guidelines. |
Reg. 1.5 |
Definition of an oil tanker |
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1.3 FPSOs and FSUs are not oil tankers and are not to be used
for the transport of oil except that, with the specific agreement by
the flag and relevant coastal States on a voyage basis, produced
oil may be transported to port in abnormal and rare circumstances. |
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2Major conversion |
Reg. 1.9 |
2.1 The deadweight to be used for determining the application of
provisions of Annex I is the deadweight assigned to an oil tanker at
the time of the assignment of the load lines. If the load lines are
reassigned for the purpose of altering the deadweight, without
alteration of the structure of the ship, any substantial alteration of the
deadweight consequential upon such reassignments should not be
construed as a ‘‘major conversion’’ as defined in regulation 1.9.
However, the IOPP Certificate should indicate only one deadweight
of the ship and be renewed on every reassignment of load lines. |
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2.2 If a crude oil tanker of 40,000 tonnes deadweight and above
delivered on or before 1 June 1982 as defined in regulation 1.28.3 satisfying the requirements of COW changes its trade for the
carriage of product oil* conversion to CBT or SBT and reissuing of
the IOPP Certificate will be necessary (see paragraph 19 below).
Such conversion should not be considered as a ‘‘major conversion’’ as defined in regulation 1.9. |
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2.3When an oil tanker is used solely for the storage of oil and is
subsequently put into service in the transport of oil, such a change of
function should not be construed as a ‘‘major conversion’’ as defined
in regulation 1.9. |
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2.4 The conversion of an existing oil tanker to a combination
carrier, or the shortening of a tanker by removing a transverse
section of cargo tanks, should constitute a ‘‘major conversion’’ as
defined in regulation 1.9. |
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2.5 The conversion of an existing oil tanker to a segregated ballast
tanker by the addition of a transverse section of tanks should
constitute a ‘‘major conversion’’ as defined in regulation 1.9 only
when the cargo-carrying capacity of the tanker is increased. |
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2.6 When a ship built as a combination carrier operates exclusively
in the bulk cargo trade, the ship may be treated as a ship other than
an oil tanker and Form A of the Record of Construction and
Equipment should be issued to the ship. The change of such a ship
from the bulk trade to the oil trade should not be construed as a ‘‘major conversion’’ as defined in regulation 1.9. |
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3Definition of ‘‘segregated ballast’’ |
Reg. 1.18 |
3.1 The segregated ballast system should be a system which is ‘‘completely separated from the cargo oil and fuel systems’’ as required by regulation 1.18. Nevertheless, provision may be made for emergency discharge of the segregated ballast by means of a connection to a cargo pump through a portable spool piece. In this case non-return valves should be fitted on the segregated ballast connections to prevent the passage of oil to the segregated ballast tanks. The portable spool piece should be mounted in a conspicuous position in the pump-room and a permanent notice restricting its use should be prominently displayed adjacent to it. |
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3.2 Sliding type couplings should not be used for expansion purposes where lines for cargo oil or fuel oil pass through tanks for segregated ballast, and where lines for segregated ballast pass through cargo oil or fuel oil tanks. This interpretation is applicable to ships, the keel of which is laid, or which are at a similar stage of construction, on or after 1 July 1992. |
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4 Unforeseen delay in delivery of ships |
Reg. 1.9 |
4.1 For the purpose of defining the category of a ship under regulation 1.28, a ship for which the building contract (or keel laying) and delivery were scheduled before the dates specified in these regulations, but which has been subject to delay in delivery beyond the specific date due to unforeseen circumstances beyond the control of the builder and the owner, may be accepted by the Administration as a ship of the category related to the estimated date of delivery. The treatment of such ships should be considered by the Administration on a case-by-case basis, bearing in mind the particular circumstances. |
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4.2 It is important that ships delivered after the specified dates due
to unforeseen delay and allowed to be treated as a ship of the
category related to the estimated date of delivery by the
Administration should also be accepted as such by port States. In
order to ensure this, the following practice is recommended to
Administrations when considering an application for such a ship: |
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.1 the Administration should thoroughly consider applications
on a case-by-case basis, bearing in mind the
particular circumstances. In doing so in the case of a
ship built in a foreign country, the Administration may
require a formal report from the authorities of the
country in which the ship was built, stating that the
delay was due to unforeseen circumstances beyond the
control of the builder and the owner; |
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.2 when a ship is treated as a ship of the category related
to the estimated date of delivery upon such an
application, the IOPP Certificate for the ship should be
endorsed to indicate that the ship is accepted by the
Administration as such a ship; and |
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.3 the Administration should report to the Organization on
the identity of the ship and the grounds on which the
ship has been accepted as such a ship. |
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5 Definition of generation of ships |
Regs. 1.28.2, 1.28.4, 1.28.6, 1.28.7, 1.28.8 |
For the purpose of defining the ships in accordance with regulations
1.28.2, 1.28.4, 1.28.6, 1.28.7, 1.28.8, a ship which falls into any
one of the categories listed in subparagraphs 1, 2, 3, 4.1, 4.2, or 4.3
of these paragraphs should be considered as a ship falling under the
corresponding definition. |
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6 Annex I substances which through their physical
properties inhibit effective product/water
separation and monitoring |
Reg. 2.4 |
6.1 The Government of the receiving Party should establish
appropriate measures in order to ensure that provisions of 6.2
are complied with. |
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6.2 A tank which has been unloaded should, subject to the
provisions of 6.3, be washed and all contaminated washings should
be discharged to a reception facility before the ship leaves the port
of unloading for another port. |
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6.3 At the request of the ship’s master, the Government of the
receiving Party may exempt the ship from the requirements referred
to in 6.2, where it is satisfied that: |
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.1 the tank unloaded is to be reloaded with the same
substance or another substance compatible with the
previous one and that the tanker will not be washed or
ballasted prior to loading; and |
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.2 the tank unloaded is neither washed nor ballasted at
sea if the ship is to proceed to another port unless it has
been confirmed in writing that a reception facility at that
port is available and adequate for the purpose of
receiving the residues and solvents necessary for the
cleaning operations. |
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6.4 An exemption referred to in 6.3 should only be granted by the
Government of the receiving Party to a ship engaged in voyages to ports or terminals under the jurisdiction of other Parties to the
Convention. When such an exemption has been granted it should be
certified in writing by the Government of the receiving Party. |
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6.5 In the case of ships retaining their residues on board and
proceeding to ports or terminals under the jurisdiction of other
Parties to the Convention, the Government of the receiving Party is
advised to inform the next port of call of the particulars of the ship
and cargo residues, for their information and appropriate action for
the detection of violations and enforcement of the Convention. |
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7 Conditions for waiver |
Regs. 3.4, 3.5, 14.5.3 |
The International Oil Pollution Prevention Certificate should contain
sufficient information to permit the port State to determine if the ship
complies with the waiver conditions regarding the phrase ‘‘restricted
voyages as determined by the Administration’’. This may include a
list of ports, the maximum duration of the voyage between ports
having reception facilities, or similar conditions as established by the
Administration. |
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8 Voyages of 72 hours or less in duration |
Regs. 3.4 and 3.5.2.2 |
The time limitation ‘‘of 72 hours or less in duration’’ in regulations 3.4 and 3.5.2.2.2 should be counted: |
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.1 from the time the tanker leaves the special area, when a
voyage starts within a special area; or |
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.2 from the time the tanker leaves a port situated outside
the special area to the time the tanker approaches a
special area. |
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9 Definition of ‘‘all oily mixtures’’ |
Regs. 3.4 and 3.5.2.2.3 |
The phrase ‘‘all oily mixtures’’ in regulations 3.4 and 3.5.2.2.3 includes
all ballast water and tank washing residues from cargo oil tanks. |
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10 Equivalents |
Reg. 5 |
10.1 Acceptance by an Administration under regulation 5 of any
fitting, material, appliance, or apparatus as an alternative to that
required by Annex I includes type approval of pollution prevention
equipment which is equivalent to that specified in resolution
A.393(X)†. An Administration that allows such type approval shall
communicate particulars thereof, including the test results on which
the approval of equivalency was based, to the Organization in
accordance with regulation 5.2. |
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With regard to the term ‘‘appropriate action, if any’’ in regulation 5.2,
any Party to the Convention that has an objection to an equivalency
submitted by another Party should communicate this objection to
the Organization and to the Party which allowed the equivalency
within one year after the Organization circulates the equivalency to
the Parties. The Party objecting to the equivalency should specify
whether the objection pertains to ships entering its ports. |
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11 Survey and inspection |
Reg. 6.1.3 and 6.1.4 |
11.1 Intermediate and annual survey for ships not required
to hold an IOPP Certificate |
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The applicability of regulations 6.1.3 and 6.1.4 to ships which are
not required to hold an International Oil Pollution Prevention
Certificate should be determined by the Administration. |
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12 Designation of the type of oil tankers |
Regs. 7, 19 |
12.1 Oil tankers must be designated on the Supplement Form B to
the IOPP Certificate as either ‘‘crude oil tanker’’, ‘‘product carrier’’ or ‘‘crude oil/product carrier’’. Furthermore, the requirements contained
in regulation 19 differ for different age categories of ‘‘crude oil
tankers’’ and ‘‘product carriers’’, and compliance with these
provisions is recorded on the IOPP Certificate. Oil trades in which
different types of oil tankers are allowed to be engaged are as
follows: |
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.1 Crude oil/product carrier is allowed to carry either
crude oil or product oil, or both simultaneously; |
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.2 Crude oil tanker is allowed to carry crude oil but is
prohibited from carrying product oil; and |
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.3 Product carrier is allowed to carry product oil but is
prohibited from carrying crude oil. |
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12.2 In determining the designation of the type of oil tanker on the
IOPP Certificate based on the compliance with the provisions for
SBT, PL, CBT and COW, the following standards should apply. |
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12.3 Oil tankers delivered after 1 June 1982 as defined in
regulation 1.28.4 of less than 20,000 tonnes deadweight |
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12.3.1 These oil tankers may be designated as ‘‘crude oil/product
carriers’’. |
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12.4 Oil tankers delivered after 1 June 1982 as defined in
regulation 1.28.4 of 20,000 tonnes deadweight and
above |
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12.4.1 Oil tankers satisfying the requirements for SBT + PL+ COW
may be designated as ‘‘crude oil/product carrier’’. |
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12.4.2 Oil tankers satisfying the requirements for SBT + PL but not
COW should be designated as ‘‘product carrier’’. |
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12.4.3 Oil tankers of 20,000 tonnes deadweight and above but
less than 30,000 tonnes deadweight not carrying crude oil, fuel oil,
heavy diesel oil or lubricating oil as cargo, not fitted with SBT + PL,
should be designated as ‘‘product carrier’’. |
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12.5 Oil tankers delivered on or before 1 June 1982 as
defined in regulation 1.28.3 but delivered after 31
December 1979 as defined in regulation 1.28.2 of
70,000 tonnes deadweight and above |
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12.5.1 The oil tankers satisfying the requirements for SBT may be
designated as ‘‘crude oil/product carrier’’. |
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12.6 Oil tankers delivered on or before 1 June 1982 as
defined in regulation 1.28.3 of less than 40,000
tonnes deadweight |
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12.6.1 These oil tankers may be designated as ‘‘crude oil/product
carrier’’. |
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12.7 Oil tankers delivered on or before 1 June 1982 as
defined in regulation 1.28.3 of 40,000 tonnes
deadweight and above |
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12.7.1 Oil tankers satisfying the requirements for SBT should be
designated as ‘‘crude oil/product carrier’’. |
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12.7.2 Oil tankers satisfying the requirements for COW only
should be designated as ‘‘crude oil tanker’’. |
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12.7.3 Oil tankers satisfying the requirements for CBT should be
designated as ‘‘product carrier’’. |
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13 New form of IOPP Certificate or its Supplement |
Reg. 9 |
In the case where the form of the IOPP Certificate or its Supplement
is amended, and this amendment does not cause a shortening of the
validity of the ship’s IOPP Certificate, the existing form of the
certificate or supplement which is current when the amendment
enters into force may remain valid until the expiry of that certificate,
provided that, at the first survey after the date of entry into force of
the amendment, necessary changes are indicated in the existing
certificate or supplement by means of suitable corrections, e.g.
striking over the invalid entry and typing the new entry. |
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14 Revalidation of an IOPP Certificate |
Reg. 10 |
Where an annual or an intermediate survey required in regulation 6 of Annex I of MARPOL 73/78 is not carried out within the period
specified in that regulation, the IOPP Certificate ceases to be valid.
When a survey corresponding to the requisite survey is carried out
subsequently, the validity of the Certificate may be restored without
altering the anniversary and expiry date of the original Certificate and
the Certificate endorsed to this effect. The thoroughness and
stringency of such survey will depend on the period for which the
prescribed survey has elapsed and the conditions of the ship. |
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15 Capacity of sludge tanks |
Reg. 10 |
15.1 To assist Administrations in determining the adequate
capacity of sludge tanks, the following criteria may be used as
guidance. These criteria should not be construed as determining the
amount of oily residues which will be produced by the machinery
installation in a given period of time. The capacity of sludge tanks
may, however, be calculated upon any other reasonable assumptions.
For a ship the keel of which is laid or which is at a similar stage
of construction on or after 31 December 1990, the guidance given
in items .4 and .5 below should be used in lieu of the guidance
contained in items .1 and .2. |
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.1 For ships which do not carry ballast water in oil fuel
tanks, the minimum sludge tank capacity (V1) should be
calculated by the following formula:
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V1 = |
K1CD (m3) |
where: |
K1 = |
0.01 for ships where heavy fuel oil is
purified for main engine use, or 0.005
for ships using diesel oil or heavy fuel
oil which does not require purification
before use, |
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C = |
daily fuel oil consumption (tonnes); and |
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D = |
maximum period of voyage between
ports where sludge can be discharged
ashore (days). In the absence of precise
data a figure of 30 days should be used. |
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.2 When such ships are fitted with homogenizers, sludge
incinerators or other recognized means on board for the
control of sludge, the minimum sludge tank capacity
(V1) should, in lieu of the above, be:
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V1 = |
1 m3 for ships of 400 gross tonnage and above
but less than 4000 gross tonnage, or 2 m3 for
ships of 4000 gross tonnage and above. |
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.3 For ships which carry ballast water in fuel oil tanks, the
minimum sludge tank capacity (V2) should be calculated
by the following formula:
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V2 = |
V1 + K2B (m3) |
where: |
V1 = |
sludge tank capacity specified in .1 or
.2 above in m3, |
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K2 = |
0.01 for heavy fuel oil bunker tanks, or
0.005 for diesel oil bunker tanks, and |
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B = |
capacity of water ballast tanks which
can also be used to carry oil fuel
(tonnes). |
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.4 For ships which do not carry ballast water in fuel oil
tanks, the minimum sludge tank capacity (V1) should be
calculated by the following formula:
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V1 = |
K1CD (m3) |
where: |
K1 = |
0.015 for ships where heavy fuel oil is
purified for main engine use or 0.005
for ships using diesel oil or heavy fuel
oil which does not require purification
before use, |
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C = |
daily fuel oil consumption (m3); and |
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D = |
maximum period of voyage between
ports where sludge can be discharged
ashore (days). In the absence of precise
data, a figure of 30 days should be
used. |
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.5 For ships fitted with homogenizers, sludge incinerators
or other recognized means on board for the control of
sludge, the minimum sludge tank capacity should be: |
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.5.1 50% of the value calculated according to item .4 above;
or |
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.5.2 1 m3 for ships of 400 gross tonnage and above but
less than 4000 gross tonnage or 2 m3 for ships of
4000 gross tonnage and above; whichever is the
greater. |
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15.2 Administrations should establish that in a ship the keel of
which is laid or which is at a similar stage of construction on or after
31 December 1990, adequate tank capacity, which may include
the sludge tank(s) referred to under 15.1 above, is available also for
leakage, drain and waste oils from the machinery installations. In
existing installations this should be taken into consideration as far as
reasonable and practicable. |
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16 Overboard connection of sludge tanks |
Reg. 12.2 |
15.1 Ships having piping to and from sludge tanks to overboard discharge
outlets, other than the standard discharge connection referred to in
regulation 13, installed prior to 4 April 1993 may comply with
regulation 12.2 by the installation of blanks in this piping. |
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17 Cleaning of sludge tanks and discharge of residues |
Reg. 12.3 |
17.1 To assist Administrations in determining the adequacy of the
design and construction of sludge tanks to facilitate their cleaning
and the discharge of residues to reception facilities, the following
guidance is provided, having effect on ships the keel of which is laid
or which is at a similar stage of construction on or after
31 December 1990: |
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.1 sufficient man-holes should be provided such that,
taking into consideration the internal structure of the
sludge tanks, all parts of the tank can be reached to
facilitate cleaning; |
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.2 sludge tanks in ships operating with heavy oil, that
needs to be purified for use, should be fitted with
adequate heating arrangements or other suitable
means to facilitate the pumpability and discharge of
the tank content; |
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.3 there should be no interconnections between the
sludge tank discharge piping and bilge-water piping
other than possible common piping leading to the
standard discharge connection referred to in regulation
13. However, arrangements may be made for draining
of settled water from the sludge tanks by means of
manually operated self-closing valves or equivalent
arrangements; and |
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.4 the sludge tank should be provided with a designated
pump for the discharge of the tank content to reception
facilities. The pump should be of a suitable type,
capacity and discharge head, having regard to the
characteristics of the liquid being pumped and the size
and position of tank(s) and the overall discharge time. |
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18 Automatic stopping device required by
regulation 15.3.2 |
Regs. 14, 15 |
Regulation 15.3.2 includes a reference to regulation 14.7 which
requires both a 15 ppm bilge alarm and a stopping device which will
ensure that the discharge is automatically stopped when the oil
content of the effluent exceeds 15 ppm. Since, however, this is not a
requirement of regulation 14 for ships of less than 10,000 gross
tonnage, such ships need not be required to be equipped with such
alarm and stopping device if no effluent from machinery space bilge
is to be discharged within special areas. Conversely, the discharge of
effluent within special areas from ships without 15ppm bilge alarm
and an automatic stopping device is a contravention of the
Convention even if the oil content of the effluent is below 15 ppm. |
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19 Control of discharge of ballast water from oil fuel
tanks |
Reg. 14.1 |
19.1 The second sentence of regulation 14.1 should be
interpreted as follows:
Any ship of 400 gross tonnage and above but less than 10,000
gross tonnage: |
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.1 which does not carry water ballast in oil fuel tanks
should be fitted with 15 ppm oil filtering equipment for
the control of discharge of machinery space bilges; |
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.2 which carries water ballast in oil fuel tanks should be
fitted with the equipment required by regulation 14.2 for the control of machinery space bilges and dirty
ballast water from oil fuel tanks. Ships on which it is not
reasonable to fit this equipment should retain on board
dirty ballast water from oil fuel tanks and discharge it to
reception facilities. |
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19.2 The above equipment should be of adequate capacity to deal
with the quantities of effluent to be discharged.
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20 Oil filtering equipment |
Regs. 14.1, 14.2 |
Oil filtering equipment referred to in regulations 14.1 and 14.2 is a
15 ppm bilge separator and may include any combination of a
separator, filter or coalescer and also a single unit designed to
produce an effluent with oil content not exceeding 15 ppm
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21 Waivers for restricted voyages |
Reg. 14.5.3.4 |
The International Oil Pollution Prevention Certificate should contain
sufficient information to permit the port State to determine if the ship
complies with the waiver conditions regarding the phrase ‘‘restricted
voyages as determined by the Administration’’. This may include a
list of ports, the maximum duration of the voyage between ports
having reception facilities, or similar conditions as established by the
Administration. |
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22 Controls of discharge of oil |
Reg. 15 |
22.1 Transfer of non-oil-cargo related oily residues to slop
tanks of oil tankers |
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22.1.1 If non-oil-cargo related oily residues are transferred to slop
tanks of oil tankers, the discharge of such residues should be in
compliance with regulation 34. |
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22.1.2 The above interpretation should not be construed as
relaxing any existing prohibition of piping arrangements connecting
the engine-room and slop tanks which may permit cargo to enter the
machinery spaces. Any arrangements provided for machinery space
bilge discharges into slop tanks should incorporate adequate means
to prevent any backflow of liquid cargo and gases into the
machinery spaces. Any such arrangements do not constitute a
relaxing of the requirements of regulation 14 with respect to oil
filtering equipment. |
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23 Oil fuel |
Reg. 16.2 |
23.1 Large quantities of oil fuel |
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23.1.1 The phrase ‘‘large quantities of oil fuel’’ in regulation 16.2 refers to ships which are required to stay at sea for extended periods
because of the particular nature of their operation and trade. Under
the circumstances considered, these ships would be required to fill
their empty oil fuel tanks with water ballast in order to maintain
sufficient stability and safe navigation conditions. |
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23.1.2 Such ships may include inter alia certain large fishing
vessels or ocean-going tugs. Certain other types of ships which for
reasons of safety, such as stability, may be required to carry ballast in
oil fuel tanks may also be included in this category. |
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24 Application of regulation 16.4 |
Reg. 16.4 |
When the separation of oil fuel tanks and water ballast tanks is
unreasonable or impracticable for ships covered by regulation 16.4,
ballast water may be carried in oil fuel tanks, provided that such
ballast water is discharged into the sea in compliance with
regulations 15.2, 15.3, 15.5 and 15.6 or into reception facilities
in compliance with regulation 15.9. |
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25 Oil tankers used for the storage of dirty ballast |
Regs. 18, 19, 20, 33 and 35 |
When an oil tanker is used as a floating facility to receive dirty ballast
discharged from oil tankers, such a tanker is not required to comply
with the provisions of regulations 18, 19, 20, 33 and 35. |
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26 SBT, CBT, COW and PL requirements |
Reg. 18.3.2 |
26.1 Capacity of SBT |
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For the purpose of application of regulation 18.3.2, the following
operations of oil tankers are regarded as falling within the category
of exceptional cases: |
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.1 when combination carriers are required to operate
beneath loading or unloading gantries; |
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.2 when tankers are required to pass under a low bridge; |
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.3 when local port or canal regulations require specific
draughts for safe navigation; |
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.4 when loading and unloading arrangements require the
tanker to be at a draught deeper than that achieved
when all segregated ballast tanks are full; |
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.5 close-up inspection or/and steel thickness measurement
using rafts where permitted by the rules; and |
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.6 tank hydrostatic pressure tests. |
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27 Segregated ballast conditions for oil tankers
less than 150 metres in length |
Reg. 18.5 |
27.1 In determining the minimum draught and trim of oil tankers
less than 150 metres in length to be qualified as SBT oil tankers, the
Administration should follow the guidance set out in appendix 1. |
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27.2 The formulae set out in appendix 1 replace those set out in
regulation 18.2, and these oil tankers should also comply with the
conditions laid down in regulations 18.3 and 18.4 in order to be
qualified as SBT oil tankers. |
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28 Oil tankers as defined in regulation 1.28.3 of 40,000 tonnes deadweight and above
with CBT and COW |
Regs. 18.7, 18.8 |
28.1 Oil tankers as defined in regulation 1.28.3 of 40,000 tonnes
deadweight and above which are fitted with CBT and COW and
designated as ‘‘crude oil/product carriers’’ in the Supplement to the
IOPP Certificate operate as follows: |
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.1 They should always operate with CBT and neither crude
oil nor product oil should be carried in dedicated clean
ballast tanks; and |
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.2 When carrying a complete or partial cargo of crude oil
they should, in the crude carrying tanks, also operate
with COW for sludge control. |
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28.2 Approved procedures by the Administration for changeover
between COW and CBT modes on tankers with common or separate
independent piping and pump arrangements for cargo and (CBT)
ballast handling should be continuously acceptable as long as
carriage of crude oil in CBT mode is not given as permissible. |
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29 Capacity of CBT |
Reg. 18.8 |
29.1 For the purposes of determining the capacity of CBT, the following tanks may be included: |
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.1 segregated ballast tanks; and |
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.2 cofferdams and fore and after peak tanks, provided that
they are exclusively used for the carriage of ballast
water and are connected with permanent piping to
ballast water pumps. |
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30 CBT oil content meter |
Reg. 18.8.3 |
The discharge of ballast from the dedicated clean ballast tanks
should be continuously monitored (but not necessarily recorded) by
the oil content meter required by regulation 18.8.3 so that the oil
content, if any, in the ballast water can be observed from time to
time. This oil content meter is not required to come into operation
automatically. |
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31 Protective location of SBT |
Regs. 18.12 to 18.15 |
31.1 The measurement of the minimum width of wing tanks and of
the minimum vertical depth of double bottom tanks should be taken
and values of protective areas (PAc and PAs) should be calculated in
accordance with the ‘‘Interim recommendation for a unified
interpretation of regulations 18.12 – 18.15 – Protective location of
segregated ballast spaces’’ set out in appendix 2. |
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31.2 Ships being built in accordance with this interpretation should be regarded as meeting the requirements of regulations 18.12 – 18.15 and would not need to be altered if different requirements were to result from a later interpretation. |
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31.3 If, in the opinion of the Administration, any oil tanker the keel of which was laid or which was at a similar stage of construction before 1 July 1980 complies with the requirements of regulation 18.12 – 18.15 without taking into account the above Interim Recommendation, the Administration may accept such tanker as complying with regulations 18.12 – 18.15. |
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32 Oil tankers with independent tanks |
Reg. 19 |
Oil tankers with independent tanks are considered as double-hull oil
tankers, provided that they are designed and constructed to be such
that the minimum distances between the cargo tank boundaries and
ship bottom and side-shell plating comply with the provisions of
regulation 19. |
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33 Width of wing tanks and height of double bottom
tanks at turn of the bilge area |
Reg. 19.3.3 |
The requirements of Reg. 19.3.3 at turn of the bilge areas are
applicable throughout the entire tank length. |
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34 Aggregate capacity of ballast tanks |
Reg. 19.4 |
34.1 Any ballast carried in localized inboard extensions, indentations
or recesses of the double hull, such as bulkhead stools, should
be excess ballast above the minimum requirement for segregated
ballast capacity according to regulation 18. |
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34.2 In calculating the aggregate capacity under regulation 19.3.4, the following should be taken into account: |
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.1 the capacity of engine-room ballast tanks should be
excluded from the aggregate capacity of ballast tanks; |
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.2 the capacity of ballast tank located inboard of double
hull should be excluded from the aggregate capacity of
ballast tanks (see figure 1). |
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.3 spaces such as void spaces located in the double hull
within the cargo tank length should be included in the
aggregate capacity of ballast tanks (see figure 2). |
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35 Definition of double side wing tanks |
Reg. 19.6.2 |
35.1 Wing tanks required for the protection of the entire cargo tank
length by regulation 19.6.2, for the purpose of compliance with
regulation 21.4.2, can be used as cargo tanks for the carriage of oil
other than heavy grade oils when the ship is provided with cargo
tanks so arranged that the capacity of each cargo tank does not
exceed 700 m3. |
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36 Definition of Category 2 oil tanker |
Reg. 20.3.2 |
Any Category 2 oil tanker must be provided with segregated ballast
tanks protectively located (SBT/PL). |
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37 Major conversion in respect of regulation 20.4 |
Reg. 20.4 |
For the purpose of determining the application date for the
requirements of regulation 20.4 of MARPOL Annex I, where an oil
tanker has undergone a major conversion, as defined in regulation 1 of MARPOL Annex I, that has resulted in the replacement of the forebody,
including the entire cargo carrying section, the major
conversion completion date of the oil tanker shall be deemed to
be the date of delivery of the ship referred to in regulation 20.4 of
MARPOL Annex I, provided that: |
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.1 the oil tanker conversion was completed before 6 July
1996; |
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.2 the conversion included the replacement of the entire
cargo section and fore-body and the tanker complies
with all the relevant provisions of MARPOL Annex I
applicable at the date of completion of the major
conversion; and |
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.3 the original delivery date of the oil tanker will apply
when considering the 15 years of age threshold
relating to the first CAS survey to be completed in
accordance with regulation 20.6 of MARPOL Annex I. |
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38 Wing tanks and double bottom spaces of tankers as
defined in regulation 1.28.5 used for water ballast |
Reg. 20.6 |
38.1 If the wing tanks and double bottom tanks referred to in
regulation 20.6 are used for water ballast, the ballast arrangement
should at least be in compliance with the Revised specifications for
oil tankers with dedicated CBT (resolution A.495(XII)). |
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39 Definition of ‘‘heavy grade oil’’ |
Reg. 21.2.2 |
The reference to ‘‘fuel oils’’ in the definition of ‘‘heavy grade oil’’ in
regulation 21.2.2 should be interpreted as referring to oils, other than
crude oils, having either a density at 15°C higher than 900 kg/m3 or
a kinematic viscosity at 50°C greater than 180 mm2/s. |
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40 Requirements for the Condition Assessment
Scheme (CAS) |
Reg. 21.6.1 |
The first CAS survey shall be carried out concurrent with the
first intermediate or renewal survey:
– after 5 April 2005, or
– after the date when the ship reaches 15 years of age,
whichever occurs later.
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41 Pump-room bottom protection |
Reg. 22.5 |
The term pump-room means a cargo pump-room. Ballast piping is
permitted to be located within the pump-room double bottom
provided any damage to that piping does not render the ship’s
pumps located in the ‘‘pump-room’’ ineffective.
The double bottom protecting the ‘‘pump-room’’ can be a void tank, a
ballast tank or, unless prohibited by other regulations, a fuel oil tank. |
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42 Tank size limitation and damage stability |
Reg. 24.1.2 |
42.1 Bottom damage assumptions |
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When applying the figures for bottom damage within the forward
part of the ship as specified in regulation 24.1.2 for the purpose of
calculating both oil outflow and damage stability, 0.3L from the
forward perpendicular should be the aftermost point of the extent of
damage. |
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43 Hypothetical oil outflow for combination carriers |
Reg. 25 |
For the purpose of calculation of the hypothetical oil outflow for
combination carriers: |
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.1 the volume of a cargo tank should include the volume
of the hatchway up to the top of the hatchway
coamings, regardless of the construction of the hatch,
but may not include the volume of any hatch cover; and |
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.2 for the measurement of the volume to moulded lines,
no deduction should be made for the volume of internal
structures. |
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44 Calculation of hypothetical oil outflow |
Reg. 25.1.2 |
In a case where the width bi is not constant along the length of a
particular wing tank, the smallest bi value in the tank should be used for
the purposes of assessing the hypothetical outflows of oil Oc and Os. |
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45 Intact stability |
Reg. 27 |
42.1 Bottom damage assumptions |
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45.1 The vessel should be loaded with all cargo tanks filled to a
level corresponding to the maximum combined total of vertical
moment of volume plus free surface inertia moment at 0° heel, for
each individual tank. Cargo density should correspond to the
available cargo deadweight at the displacement at which transverse
KM reaches a minimum value, assuming full departure consumables
and 1% of the total water ballast capacity. The maximum free
surface moment should be assumed in all ballast conditions. For the
purpose of calculating GM0, liquid free surface corrections should be
based on the appropriate upright free surface inertia moment. The
righting lever curve may be corrected on the basis of liquid transfer
moments. |
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45.2 For proving compliance with regulation 27 of Annex I to
MARPOL 73/78, as an alternative to the loading case described in
MARPOL Unified Interpretation 45.1 it is accepted to carry out an
extensive analysis covering all possible combinations of cargo and
ballast tank loading. For such extensive analysis conditions, it is
considered that: |
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.1 weight, centre of gravity co-ordinates and free surface
moment for all tanks should be according to the actual
content considered in the calculations; and |
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.2 the extensive calculations should be carried out in
accordance with the following:. |
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.2.1 the draughts should be varied between light
ballast and scantling draught; |
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.2.2 consumables including but not restricted to fuel
oil, diesel oil and fresh water corresponding to
97%, 50% and 10% content should be considered; |
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.2.3 for each draught and variation of consumables,
the available deadweight should comprise ballast
water and cargo, such that combinations between
maximum ballast and minimum cargo and
vice versa are covered. In all cases, the number of
ballast and cargo tanks loaded should be chosen
to reflect the worst combination of VCG and free
surface effects. Operational limits on the number
of tanks considered to be simultaneously slack and exclusion of specific tanks should not be
permitted. All ballast tanks should have at least
1% content; |
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.2.4 cargo densities between the lowest and highest
intended to be carried should be considered; and |
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.2.5 sufficient steps between all limits should be
examined to ensure that the worst conditions are
identified. A minimum of 20 steps for the range
of cargo and ballast content, between 1% and
99% of total capacity, should be examined. More
closely spaced steps near critical parts of the
range may be necessary. |
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At every stage the criteria described in paragraph 1 of regulation 27 should be met. |
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46 Operating draught |
Reg. 28.1 |
With regard to the term ‘‘any operating draught reflecting actual
partial or full load conditions’’, the information required should
enable the damage stability to be assessed under conditions the
same as or similar to those under which the ship is expected to
operate. |
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47 Suction wells |
Reg. 28.2 |
For the purpose of determining the extent of assumed damage
under regulation 28.2, suction wells may be neglected, provided
such wells are not excessive in area and extend below the tank for a
minimum distance and in no case more than half the height of the
double bottom. |
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48 Tanks with smooth walls |
Reg. 29.2.3.3 |
The term ‘‘tanks with smooth walls’’ should be taken to include the
main cargo tanks of oil/bulk/ore carriers which may be constructed
with vertical framing of a small depth. Vertically corrugated
bulkheads are considered smooth walls. |
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49 Pumping and piping arrangements |
Reg. 29.2.3.3 |
49.1 Piping arrangements for discharge above
the waterline |
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49.1.1 Under regulation 30.2, lines for discharge to the sea above
the waterline must be led either: |
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.1 to a ship’s discharge outlet located above the waterline
in the deepest ballast condition; or |
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.2 to a midship discharge manifold or, where fitted, a stern
or bow loading/discharge facility above the upper deck. |
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49.1.2 The ship’s side discharge outlet referred to in 49.1.1.1
should be so located that its lower edge will not be submerged
when the ship carries the maximum quantity of ballast during its
ballast voyages, having regard to the type and trade of the ship. The
discharge outlet located above the waterline in the following ballast
condition will be accepted as complying with this requirement: |
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.1 on oil tankers not provided with SBT or CBT, the ballast
condition when the ship carries both normal departure
ballast and normal clean ballast simultaneously; and |
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.2 on oil tankers provided with SBT or CBT, the ballast
condition when the ship carries ballast water in
segregated or dedicated clean ballast tanks, together
with additional ballast in cargo oil tanks in compliance
with regulation 18.3. |
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49.1.3 The Administration may accept piping arrangements
which are led to the ship’s side discharge outlet located above the
departure ballast waterline but not above the waterline in the
deepest ballast condition, if such arrangements have been fitted
before 1 January 1981. |
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49.1.4 Although regulation 30.2 does not preclude the use of the
facility referred to in 49.1.1.2 for the discharge of ballast water, it is
recognized that the use of this facility is not desirable, and it is
strongly recommended that ships be provided with either the side
discharge outlets referred to in 49.1.1.1 or the part flow
arrangements referred to in regulation 30.6.5. |
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50 Small diameter line |
Reg. 30.4.2 |
50.1 For the purpose of application of regulation 30.4.2, the
cross-sectional area of the small diameter line should not exceed: |
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.1 10% of that of a main cargo discharge line for oil
tankers delivered after 1 June 1982, as defined in
regulation 1.28.4, or oil tankers delivered on or before
1 June 1982, as defined in regulation 1.28.3, not
already fitted with a small diameter line; or |
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.2 25% of that of a main cargo discharge line for oil
tankers delivered on or before 1 June 1982, as defined
in regulation 1.28.3, already fitted with such a line. (See
paragraph 4.4.5 of the revised COW Specifications
contained in resolution A.446(XI) as amended by the
Organization by resolutions A.497(XII) and A.897(21)). |
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50.2 Connection of the small diameter line to the
manifold valve |
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The phrase ‘‘connected outboard of’’ with respect to the small
diameter line for discharge ashore should be interpreted to mean a
connection on the downstream side of the tanker’s deck manifold
valves, both port and starboard, when the cargo is being discharged.
This arrangement would permit drainage back from the tanker’s cargo lines to be pumped ashore with the tanker’s manifold valves
closed through the same connections as for main cargo lines (see
the sketch shown in appendix 3). |
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51 Part flow system specifications |
Reg. 30.6.5.2 |
The Specifications for the Design, Installation and Operation of a Part
Flow System for Control of Overboard Discharges referred to in
regulation 30.6.5.2 is set out in appendix 4. |
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52 Examples of positive means |
Reg. 30.7 |
Examples of positive means may take the form of blanks, spectacle
blanks, pipeline blinds, evacuation or vacuum systems, or air or
water pressure systems. In the event that the evacuation or vacuum
systems, or air or water pressure systems are used, then these
systems are to be equipped with both a pressure gauge and alarm
system to enable the continuous monitoring of the status of the
pipeline section, and thereby the valve integrity, between the sea
chest and inboard valves. |
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53 Total quantity of discharge |
Reg. 34.1.5 |
The phrase ‘‘the total quantity of the particular cargo of which the
residue formed a part’’ in regulation 34.1.5 relates to the total
quantity of the particular cargo which was carried on the previous
voyage and should not be construed as relating only to the total
quantity of cargo which was contained in the cargo tanks into which
water ballast was subsequently loaded. |
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54 Shipboard oil pollution emergency plan |
Reg. 37.1 |
Equivalent provision for application of requirement for oil
pollution emergency plans |
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Any fixed or floating drilling rig or other offshore installation when
engaged in the exploration, exploitation or associated offshore
processing of sea-bed mineral resources, which has an oil pollution
emergency plan co-ordinated with, and approved in accordance with
procedures established by, the coastal State, should be regarded as
complying with regulation 37. |
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55 Adequate reception facilities for substances
regulated by regulation 2.4 |
Reg. 38 |
Unloading ports receiving substances regulated by regulation 2.4 (which include inter alia high-density oils) should have adequate
facilities dedicated for such products, allowing the entire tankcleaning
operation to be carried out in the port, and should have
adequate reception facilities for the proper discharge and reception of cargo residues and solvent necessary for the cleaning operation in
accordance with paragraph 6.2 of the Unified Interpretations. |
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56 Requirements for fixed or floating platforms |
Reg. 39 Art. 2(3)(b)(ii) |
56.1 Application of MARPOL 73/78 |
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56.2 There are five categories of discharges that may be
associated with the operation of fixed or floating platforms covered
by this regulation when engaged in the exploration and exploitation
of mineral resources, i.e.: |
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.1 machinery space drainage; |
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.2 offshore processing drainage; |
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.3 production water discharge; |
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.4 displacement water discharge; and |
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.5 contaminated seawater from operational purposes such
as produced oil tank cleaning water, produced oil tank
hydrostatic testing water, water from ballasting of
produced oil tank to carry out inspection by rafting. |
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Only the discharge of machinery space drainage and contaminated
ballast should be subject to MARPOL 73/78 (see diagram shown in
appendix 5). |
*
†
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