Specifications for 0.50% sulphur fuels and the PAS from ISO: IBIA explains
IBIA says it has been getting queries from several members about when ISO specifications for fuels meeting the 0.50% sulphur limit will be available. Every time, IBIA has explained that existing ISO 8217 specifications will still apply, and the Publicly Available Specification (PAS 23263) from ISO would not introduce any new specifications but rather help explain how ISO 8217 will continue to apply.
The long-awaited document; “ISO/PAS 23263:2019 Petroleum products — Fuels (class F) — Considerations for fuel suppliers and users regarding marine fuel quality in view of the implementation of maximum 0,50 % sulphur in 2020” has now been published and is available to purchase from the ISO website.
It confirms that ISO 8217 specifications still apply to fuels meeting the 0.50% sulphur limit, and provides technical advice on fuel characteristics that might apply to particular fuels for kinematic viscosity, cold flow properties, stability, ignition characteristic and catalyst fines. In addition, it provides information on how to consider compatibility between fuels, including test methods for checking whether fuels are compatible.
In responses to member queries about what specifications will apply to fuels meeting the 0.50% sulphur limit, and when they have been asking for the “latest” or “typical” specifications for very low sulphur fuel oil (VLSFO) produced to meet the 0.50% sulphur limit, IBIA has provided answers that it believes may be useful for all its members, which it shares here.
First of all, there are no new specifications for 0.50% sulphur fuels. They can still be sold under existing ISO 8217 specifications, preferably the latest edition, ISO 8217:2017, as this includes some extra reporting requirements on cold flow properties for some distillate fuels.
Fuels with maximum 0.50% sulphur will still need to meet ISO 8217 specifications, and they can still be classified in accordance with Table 1 for distillate marine (DM) fuels or Table 2 for residual marine (RM) fuels, which define the maximum, and some minimum, parameters limits for a number of fuel grades (specifications).
It may be that instead of using RMG 380 – the most commonly used ISO 8217 specification for RM fuels today – many of the fuels expected to be available would be better described by using other RM specifications in Table 2 of ISO 8217, such as RMA 10, RMB 30, RMD 80 or RME/RMG 180 because many will have lower viscosity than the typical high sulphur fuel oils (HSFOs) sold today.
For distillate fuels (DM, Table 1 of ISO 8217), we may see more DMB-grade fuels returning to the market. Today most distillates are sold as DMA-grade gasoil meeting a 0.10% sulphur limit, as this is the grade most ships use to meet the legal requirement in emission control areas (ECAs) and at berth in European Union ports.
Fuel testing agencies have, between them, already tested thousands of samples of VLSFO produced to meet the 0.50% sulphur limit, and have reported considerable variations in viscosity and density. Viscosity in the tested samples is said to typically range from 30 cSt to 380 cSt. A few samples have been below/above that range with lows of 6-7 and highs of up to 500 cSt reported, but these are rare. Density has been seen in a range of 850 to almost 998, with most above 900 kg/m3 which puts them firmly into the Table 2 (RM) specifications.
IBIA would like to remind all stakeholders that there is plenty of advice on dealing with this expected variety of fuel characteristics in the recently published Joint Industry Guidance on the supply and use of 0.50% – sulphur marine fuel.