SHORT BRIEF OF IMO ANNEX VI
Within the IMO there is now agreement about certain limitations concerning the form
of air pollution at sea. In that respect, IMO has prepared ANNEX VI, which explain today’s implementation of limitations and future limitations. Authorities in various parts of the world are taking and have taken similar steps. As a possible corrective measure, marine diesel engine manufacturers in the late 1990's were forced to modify engine design to reduce NOx emissions in accordance with Annex VI of MARPOL 73/78. In addition to these SOx limitations was also implemented in vulnerable areas as e.g. Baltic Sea.

To verify compliance with the emission limits, all installed engines are subject to annual survey in accordance with the unified survey scheme together with unscheduled inspections. After completion of the survey and subject to compliance with the emission limit values, the Flag Administration (or classification society on their behalf) will issue an International Air Pollution Prevention (IAPP) Certificate. Applicable ships must demonstrate compliance not later than the first scheduled dry-docking after 18 May 2005 but no later than 18 May 2008.

Below please find a summary of the ANNEX VI concerning diesel engines:

REGULATION 13
Nitrogen Oxides (NOx)

1.
(a) This regulation shall apply to:
(i) each diesel engine with a power output of more than 130 kW which is installed on a ship constructed on or after 1 January 2000; and
(ii) each diesel engine with a power output of more than 130 kW which undergoes a major conversion on or after 1 January 2000.

(b) This regulation does not apply to:
(i) emergency diesel engines, engines installed in lifeboats and any device or
equipment intended to be used solely in case of emergency; and
(ii) engines installed on ships solely engaged in voyages within waters subject to the
sovereignty or jurisdiction of the Administration of those ships State the flag of which
the ship is entitled to fly, provided that such engines are subject to an alternative NOx
control measure established by the Administration.

(c) Notwithstanding the provisions of sub-paragraph 'a' of this paragraph, the Administration may allow exclusion from the application of this regulation to any diesel engine which is installed on a ship constructed, or on a ship which undergoes a major conversion, before the date of entry into force of the present Protocol, provided that the ship is solely engaged in voyages to ports or offshore terminals within the Administration of those ships State the flag of which the ship is entitled to fly.

2.
(a) For the purpose of this regulation, "major conversion" means a modification of
an engine where:
(i) the engine is replaced by a new engine built on or after 1 January 2000, or
(ii) any substantial modification, as defined in the NOx Technical Code, is made
to the engine, or
(iii) the maximum continuous rating of the engine is increased by more than 10%.

(b) The NOx emission resulting from modifications referred to in the sub-paragraph
'a' of this paragraph shall be documented in accordance with the NOx Technical Code
for approval by the Administration.

3.
(a) Subject to the provision of regulation 3 of this Annex, the operation of each diesel engine to which this regulation applies is prohibited, except when the emission of nitrogen oxides (calculated as the total weighted emission of NO2) from the engine is within the following limits:
(i) 17.0 g/kWh when n is less than 130 rpm
(ii) 45.0*n(-0.2) g/kWh when n is 130 or more but less than 2000 rpm
(iii) 9.8 g/kWh when n is 2000 rpm or more where n = rated engine speed (crankshaft
revolutions per minute).
When using fuel composed of blends from hydrocarbons derived from petroleum
refining, test procedure and measurement methods shall be in accordance with the
NOx Technical Code, taking into consideration the Test Cycles and Weighting
Factors outlined in appendix V II to this Annex.

(b) Notwithstanding the provisions of sub-paragraph 'a' of this paragraph, the
operation of a diesel engine is permitted when:
(i) an exhaust gas cleaning system, approved by the Administration in accordance
with the NOx Technical Code, is applied to the engine to reduce onboard NOx
emissions at least to the limits specified in sub-paragraph 'a', or
(ii) any other equivalent method, approved by the Administration in accordance with
the relevant guidelines to be developed by the Organization, is applied to reduce
onboard NOx emissions at least to the limit specified in sub-paragraph 'a' of this
paragraph.

4.
The NOx emission limits shall be considered for review by the Organization as
necessary at a minimum of five-year intervals after entry into force of Annex VI.

5.
The Organization shall circulate to all Member States of the Organization
notification of any revisedemission requirements resulting from the review required
by paragraph '4' of this regulation, at least three years before the implementation date of the revised NOx emission limits.

REGULATION 14
Sulphur Oxides (SOx)
General requirements
The sulphur content of any fuel oil used on board ships shall not exceed 4.5% m/m.

2.
The worldwide average sulphur content of residual fuel oil supplied for use on
board ships shall be monitored based on guidelines to be developed by the
Organization.

Requirements within SOx Emission Control Areas
3.
For the purpose of this regulation, SOx Emission Control Areas shall include:
(a) The Baltic Sea area as defined in regulation 10,'1b' of Annex I;

(b) Any other sea area, including port, areas designated by the Organization in
accordance with the based on criteria and procedures for designation of SOx
Emission Control Areas with respect to the prevention of air pollution from ships
contained in appendix II III to this Annex.

4.
While ships are within SOx Emission Control Areas, at least one of the following
conditions shall be fulfilled.
(a) The sulphur content of fuel oil used on board ships in a SOx Emission Control
Area does not exceed 1.5% m/m.

(b) An exhaust gas cleaning system, approved by the Administration in accordance
with based on guidelines to be developed by the Organization, is applied to reduce the
total emission of sulphur oxides from ships, including both auxiliary and main
propulsion engines, to 6.0 g SOx/kWh or less calculated as the total weight of sulphur
dioxide emission. Waste streams from the use of such equipment shall not be
discharged into enclosed ports, harbours and estuaries unless it can be thoroughly
documented by the ship that such waste streams have no adverse impact on the
ecosystems of such enclosed ports, harbours and estuaries, based upon criteria
communicated by the authorities of the port State to the Organization. The
Organization shall circulate the criteria to all Parties to the Convention.

(c) Any other technological method that is verifiable and enforceable to limit SOx
emissions to a level equivalent to that described in sub-paragraph 'b' is applied.
These methods shall be approved by the Administration in accordance with the
guidelines developed by the Organization.

5. The sulphur content of fuel oil referred to in paragraph '1' and sub-paragraph
' 4,a' of this regulation shall be documented by the supplier as required by regulation
18 of this Annex.

6. Those ships using separate fuel oils to comply with paragraph '4a' of this
regulation shall allow sufficient time for the fuel oil service system to be fully flushed
of all fuels exceeding 1.5% m/m sulphur content prior to entry into a SOx Emission
Control Area. The volume of low sulphur fuel oils (less than or equal to 1.5% sulphur
content) in each tank as well as the date, time, and position of the ship when any fuel
changeover operation is completed, shall be recorded in such log-book as prescribed
by the Administration.

7. During the first twelve months immediately following entry into force of the
instrument present Protocol, or of an amendment to the present Protocol designating a
specific SOx. Emission Control Area under paragraph '3b' of this regulation, ships
entering that a SOx. Emission Control Area referred to in sub-paragraph '3a' of this
regulation or designated under paragraph '3b' of this regulation are exempted from
the requirements in paragraphs '4' and '6' of this regulation and from the
requirements of paragraph '5' of this regulation insofar as they relate to sub-paragraph
'4a' of this regulation.