Ultra low sulphur fuel oil and ISO Standards


Published: 12 January 2015

While the industry may be familiar with the myriad of different ISO standards that exist for marine fuels, it is important to understand how these may relate to requirements for a maximum sulphur content of 0.10% in designated ECAs pursuant to MARPOL Annex VI.

ISO standards

As has been discussed in Skuld's guide to low sulphur fuels (Guide to low sulphur fuel), there are a number of different versions of the modern ISO 8127 standards for marine fuels.

The first incarnation dates back to 1987, and since then we have had the 1996, 2005, 2010 and the 2012 (5th edition) of the standard.

While the 2005 standard is one of the most common, the 2010 has more developed criteria that users may favour but which has at times led to a premium being charged by suppliers in regions where 2005 is the norm.

In particular 2010 added the DMZ grade, changed the viscosity standard for DMB and provided specifications for hydrogen sulphide, acid number, oxidation stability and lubricity (which should not be confused with viscosity).

It has always been necessary to understand the specifications of any particular ISO standard and to ensure that the right fuel was being ordered for, and supplied to, a given vessel.


We have now passed the first full week of the coming in to effect of the ultra low sulphur fuel standards for designated Emission Control Areas (ECAs), and the industry is beginning to adjust to the new circumstances of this very significant change from 1% sulphur to 0.10% sulphur content fuel.

Important things to be aware of, amongst all the other advice given is that the ISO standards:

a. were not designed for the new products being marketed as "MARPOL compliant fuels"
As such it will be important to check the actual composition of any blended products and whether they meet particular standards required under a charterparty and are as a matter of fact suitable for a particular vessel's engines.

b. 2010 and 2012 do not expressly specify the maximum sulphur content of the fuel
This means it is up to the purchaser to expressly specify the maximum sulphur content level of any fuel to be ordered, so that it is regulatory compliant for the particular intended trade (i.e. involving an ECA or not)

Contracting advice

It is important to appreciate this interplay between the ISO standards and the MARPOL Annex VI regulations, so that for charterparties it is made clear what fuels are in fact permissible to be supplied and that for bunker orders the correct fuel is in fact purchased.

As existing period charters may make reference to older terms and requirements, both owners and charterers are well advised to carefully review the precise terms in use.

With respect to any new charterparties, it would be very much recommended to not simply adopt an older pro forma and seek to make changes by way of the fixture recap. It is recommended that for any clause related to fuel, it is individually reviewed and updated or replaced as may be appropriate.

With respect to fuel purchases, careful attention has to be paid to ensure the exact desired fuel to the exact desired standard is in fact ordered, again the use of previous pro-formas for making orders is discouraged.

Further reading

The Association has, in addition to its guide, published a number of articles for this topic.