There are several significant changes in the sixth edition of ISO 8217 to address current industry trends: the addition of a new class of distillates allowing for bio-fuel blends; the introduction of further cold flow checks for distillate fuels; and a change of the scope (Clause 1) to allow for inclusion of hydrocarbons from synthetic or renewable sources.
There have also been substantial amendments to the general requirements (Clause 5) and the allowable sulphur content in distillate fuels has been lowered. A number of informative annexes have been deleted.
The sixth edition recently published on the International Organization for Standardization (ISO) website cancels and replaces the fifth edition (ISO 8217:2012).
New approach to FAME
The sixth edition introduces DF (Distillate FAME) grades DFA, DFZ and DFB which allow up to 7% fatty acid methyl ester(s) (FAME) content by volume. Other than the 7% FAME allowance, these grades are identical to the traditional DMA, DMZ and DMB grades for all other parameters.
The DF grades have been introduced to allow for greater use of automotive diesel in the marine distillates pool, which is expected to improve fuel oil availability in some ports which may otherwise struggle to provide fuels complying with a 0.10% sulphur limit to ships. The 7% upper limit is in line with the maximum content in road diesel in most countries, and the FAME in the DF grades have be in accordance with the requirements of EN 14214 or ASTM D6751 at the time of blending.
The regular marine fuel grades; DMA, DMZ, DMB and RM (residual marine) grades shall not include FAME other than a “de minimis” level,” while DMX must be FAME-free.
In the previous edition, the “de minimis” limit was indicated as not exceeding approximately 0.1%. This has been increased to 0.5% because the working group in in charge of developing the marine fuel standards, ISO/TC28/SC4/WG6, was confident this level does not cause any operational issues based on field experience. The limit is still low enough to prevent intentional blending of FAME into marine fuel, but high enough to allow for accidental trace amounts caused by shared supply chain infrastructure with fuels for the automotive sector, and should broaden the scope for fuel availability.
Controlling cold flow
Additional requirements have been included for distillate fuels to protect ships against cold climate operability issues which have been experienced since the introduction of 0.10% sulphur limit in emission control areas (ECAs) in 2015.
Since then, some ships have experienced paraffins solidifying in tanks, especially when more paraffinic fuels have been stored in unheated tanks.
In response to these concerns, the sixth edition has introduced a requirement to report cloud point (CP) and cold filter plugging point (CFPP) in DMA/DFA and DMZ/DFZ winter grades. There is no limit specified; only a requirement to report to let the operator know in advance if the fuel will need heating.
Only DMX, a specialist niche product mainly intended for emergency generators, has limits specified for CP.
For summer distillate grades (DMA/DFA and DMZ/DFZ) the only defined cold flow property is pour point (PP). Residual fuels (RF) also have specific PP limits, but RF cold flow properties have not been an issue as such fuels are kept in heated storage tanks.
Scope & general requirements
The Scope (Clause 1) has been expanded to include fuels containing not only “hydrocarbons from petroleum crude oil” but also from oil sands and shale, and hydrocarbons from synthetic or renewable sources.
This has been amended to address the evolving composition of fuels. Hydrocarbons from synthetic and renewable sources are similar in composition to and in practice indistinguishable from petroleum hydrocarbons.
Clause 5 – General requirements, has been extensively redrafted to allow for inclusion of hydrocarbons form non-petroleum sources, and blends with a FAME component (Clause 5.1).
References to contaminants have been modified and simplified. Clause 5.2 now states: “The fuel shall be free from any material at a concentration that causes the fuel to be unacceptable for use in accordance with Clause 1 (i.e. material not at a concentration that is harmful to personnel, jeopardizes the safety of the ship, or adversely affects the performance of the machinery).
According to a FAQ document on ISO 8217:2017 just released by the International Council on Combustion Engines (CIMAC), Clause 5 in earlier versions “was continuously being misread and misunderstood, so the working group agreed to rework the wording to clarify and minimize any future misunderstanding of the intent of this clause.”
Sulphur limits have been reduced for several distillate grades. The sulphur limit for DMA and DMZ has dropped from 1.50% to 1.00% by mass. The same limits apply to the bio-blend equivalent DFA and DFC. DMX is unchanged at 1.00% maximum sulphur.
The sulphur limit has been reduced from 2.00% to 1.50% by mass for DMB, and the bio-blend equivalent, DFB, has also been given a 1.5% sulphur limit.
The reduction in sulphur limits is mainly in recognition of market trends, as these fuels rarely exceeded the new upper limits. The new limits do not correspond to any current statutory limits with the exception of DMB, which at 1.50% is in line with the current limit for passenger vessels on regular service between European Union ports (outside ECAs) until 2020.
Residual marine (RM) grades, as in the 2010 and 2012 editions, have no sulphur limits specified. These must be defined by the purchaser in line with statutory limitations.
A number of informative annexes have been deleted. Critical supporting information previously in the annexes has been moved into the body of the Standard.
In Clause 8 (Precision and interpretation of test results) it says ISO 4259, which covers the use of precision data in the interpretation of test results, shall be used in cases of dispute. It also says: “NOTE: Since all fuel testing is subject to inherent variations, the assessment of fuels as supplied is governed by the provisions of ISO 4259. More information is provided in the CIMAC guideline on the interpretation of marine fuel oil analysis test results.”
The referenced CIMAC guide is available on this link.
What next and further information
ISO 8217:2017 has not been able to address some of the issues arising from the introduction to the market of several marine fuels that do not fit into the ISO 8217 marine distillate table, designed for designed for operation in emission control areas (ECAs) with maximum 0.10% sulphur fuels.
Quality concerns specific to these less conventional types of fuel, not fitting traditional marine distillate specifications, is expected to become even more pressing with the 0.50% sulphur limit in 2020. The ISO/TC 28/SC4/WG6 has already started the process of analysing the needs.
The CIMAC Working Group 7 Fuels has collated and provided responses to “FAQs” arising in connection with the publication of ISO 8217:2017 in collaboration with the ISO Committee. It says the responses to these questions “reflect the collective thinking of the ISO Committee”. It is available on this link.
The sixth edition of the ISO 8217 marine fuel specifications is available to buy on the ISO website on this link.
Should you have any further questions or comments about the sixth edition of ISO 8217, please contact IBIA.
Report by Unni Einemo