The primary objective of the guidelines is to establish an agreed method to monitor the
average sulphur content of residual fuel oils supplied for use on board ships. A further
objective of the guidelines is to re-open the discussion in MEPC on measures to reduce SOx,
emissions from ships, should the average sulphur level in fuels, calculated on the basis of
these guidelines, show a sustained increase.
The basis for these guidelines is provided in regulation 14 (2) of Annex VI of MARPOL
73/78 and in Conference Resolution 4 (in MP/CONF.3/35), on monitoring the world wide
average sulphur content of residual fuel oil supplied for use on board ships. Among the
emissions addressed by Annex VI are emissions resulting from the combustion of fuels
containing sulphur. An upper limit for the sulphur content of fuels was set and it was further
decided to monitor the average sulphur content of fuel.
It is estimated that independent testing companies undertake up to 50,000 tests annually,
which cover between 25 and 35% of all deliveries. From the data gathered by these testing
services the current average figures for the sulphur content of residual fuels can be derived.
These figures are publicised regularly and are currently in the order of 3% by mass.
For the purpose of these guidelines the following definitions shall apply:
Fuel oil for combustion purposes delivered to and used on board ships with a
kinematic viscosity at 1000�Ž greater than or equal to 10.0 centistoke.1
Provider of sampling and testing services:
A company that, on a commercial basis, provides testing and sampling services
of bunker fuels delivered to ships for the purpose of assessing quality parameters
of these fuels, including the sulphur content.
Reference value Aw:
The value of the world-wide average sulphur content in residual fuel oils supplied
for use on board ships, based on the first three years of data collected and as
determined on the basis of paragraph 4 and 5 of these guidelines.
1 Reference is made to ISO Standard 8217 1996 4
Monitoring and calculation of yearly and three-year rolling average
Monitoring shall be based on calculation of average sulphur content of residual fuels on the basis of sampling and testing by independent testing services. Every year the average sulphur
content of residual fuels shall be calculated. After three years the reference value for
monitoring will be set as described in paragraph 5.
4.2 Calculation of yearly average
At the basis of monitoring is the calculation, on an annual basis, of the average sulphur
content of residual fuel.
The calculation of the average sulphur content is executed as follows:
For a certain calendar year, the sulphur contents of the samples analysed (one sample for
each delivery of which the sulphur content is determined by fuel oil analysis) are recorded.
The sulphur contents of the samples analysed are added up and divided by the number of
samples. The outcome of that division is the average sulphur content of residual fuel for that
As a basis for well informed decisions a graphical representation of the distribution of the
global sulphur content in residual fuels in terms of the % sulphur in increments of 0.5%
sulphur plotted against the quantity of fuel associated with each incremental sulphur content
range shall be made available by 31 January of each year.
The mathematical formula for the method of calculation described, is given in appendix 1 to
4.3 Three year rolling average
A three year rolling average shall be calculated as follows:
Setting of the reference value5
The reference value of the world wide average sulphur content of residual fuel oils
supplied for use on board ships shall be Aw, where Aw= Acr as calculated in January of the
year following the first three years in which data were collected on the basis of these
Aw shall be expressed as a percentage.
Agenda setting of consideration of measures to reduce SOx emissions6
If in any given year following the setting of the reference value, Acr exceeds Aw by a
number equal to or greater than 0.2 %, the Marine Environment Protection Committee shall
consider the need for further measures to reduce SOx emissions from ships, so as to decide
whether it should be considered a high priority item for the Committee. MEPC shall
continually review this excess value, (now 0.2%) once the reference value has been set.
Providers of sampling and testing services7
For the purpose of the initial five years operational period, there are presently 3 providers
of sampling and testing services under these guidelines
Any additional providers of sampling and testing services shall be subject to the following
They shall preferably be IACS members, but shall in any way be subject to the
approval of the Marine Environment Protection Committee, which shall apply these
They shall be provided with a technical and managerial staff of qualified
professionals providing adequate geographical coverage and local representation to
ensure quality services in a timely manner;
They shall provide services governed by a documented Code of Ethics;
They shall be independent as regards to commercial interest in the outcome of
They shall implement and maintain an internationally recognized quality system,
certified by an independent auditing body, which ensures reproducibility and
repeatability of services which are internally audited, monitored and carried out
under controlled conditions.
They shall take a significant number of samples on an annual basis for the purpose
of globally monitoring average sulphur content of residual fuels
Standardized method of calculation8
Each of the providers of sampling and testing services shall provide the necessary
information for the calculation of the average sulphur content of the residual fuels to the
Secretariat of IMO or another agreed third party on the basis of a mutually agreed format,
approved by MEPC. This party will process the information and will provide the outcome in
the agreed format to MEPC. From the viewpoint of competitive positions the information
involved shall be considered sensitive. Therefore the third party involved shall treat such
information as indicated by any party involved as confidential, without prejudice to the
information required by the Committee for the purposes of, monitoring and related decision
The costs of monitoring consist of an initial amount for setting up monitoring by the
providers listed in paragraph 7 and an annual fee to these providers for the provision of the
The costs of monitoring shall, for a 5-year operational period, be borne on a voluntary
basis by the member States listed in appendix 2 of this guideline. The experience gained shall
be evaluated by the end of the fourth year of operation. On that basis, the Marine
Environment Protection Committee, in consultation with the Secretary-General of IMO, is
invited to consider more permanent financial arrangements to cover the costs of the agreed