Bunker buyers should go for new ISO standard

The ISO 8217:2010 marine fuel specification, released on 1 July 2010, came with
tighter quality limits and new parameters. Unfortunately, the shipping industry’s reception to this revised specification has been lukewarm. According to DNV Petroleum
Services (DNVPS), less than 10% of its ship-operating clients have taken up
this standard. Perhaps they are tied to the previous standard (ISO 8217: 2005) in long
term bunker purchase contracts or charter parties, or are worried about the additional
testing costs involved and the availability of bunkers compliant with ISO 8217:2010. But
given a choice, ship operators should buy and test their fuels according to this revised
specification as it gives them added protection against poor fuel quality.
In ISO 8217:2010, the reduced limits for Aluminium and Silicon (Al+Si), also known
as cat fines, are one of the most significant changes for heavy fuel oil (HFO)
specification. While ISO 8217:2005 stipulated an 80 mg/kg maximum limit for
Al+Si in residual fuels, the new limit in ISO 8217:2010 is down to 60 mg/kg for the
higher viscosity grades, and 40 mg/kg for the lower viscosity grades.
Stricter Al+Si limits are important because the capacity of ship separators for removing
cat fines from the fuel, before it enters the engine, may not be as adequate as thought.
Ship operators have been assuming the efficiency levels of fuel treatment systems to
be up to 85%, but recent findings suggest that the reality is closer to 65%. The tighter
Al+Si limit in ISO 8217:2010 facilitates efforts by shipboard personnel to meet the
engine makers’ recommendation of not more than 15 mg/kg Al+Si in the fuel, at the
engine inlet.
Among the engine damage reported in 2011, high liner wear and broken piston
rings were frequent. Cat fines are a main cause of these costly damages. The repairs
often involve replacing mechanical components and the bill can be exorbitant if the
ship has to go off-hire. DNVPS records show that 4% of all fuels purchased
under ISO 8217:2005 would have been off specification for Al+Si if they were bought and tested against ISO 8217:2010. With its stricter requirements on bunker quality, ISO 8217:2010 helps reduce engine damage risks. Besides Al+Si, HFO grades under the
revised specification are also subject to tighter limits for ash and vanadium. In general, lower ash levels permitted in fuel imply reduced post-combustion deposits
and particulate matter emissions. Sodium is another new parameter in ISO
8217:2010. Although sea water contamination traditionally is the reason
behind elevated sodium levels in bunkers, crude sweetening processes at the refinery
is also a likely cause. In severe cases, onboard fuel treatment plant cannot reduce
the sodium levels sufficiently, and this leads to increased deposits in the post combustion areas, particularly in the turbochargers. High levels of sodium, combined with elevated vanadium content in the fuel, can further cause sticky deposits to form on
exhaust valves and exhaust gas turbines. Acid Number is also a new parameter in
ISO8217:2010. Although there is no recognized correlation between Acid
Number and the corrosive activity of a fuel, Acid Number tests indicate the possible
presence of potentially harmful components in the fuel, which may then be confirmed by investigative techniques such as Gas-Chromatography-Mass Spectrometry (GCMS)
analysis. Next, ISO 8217:2010 has introduced a limit for hydrogen sulphide (H2S) in marine fuel and also tightened the criteria for determining if a delivery has been
contaminated with used lubricating oil (ULO). The H2S parameter will be implemented
on 1 July 2012. As for the new ULO limit, which is already effective, either the combined calcium and zinc content, or calcium and phosphorus, must be above the specified limits before a fuel is deemed off-specification for ULO. This is an improvement over ISO
8217:2005, where all three components (i.e. calcium, zinc and phosphorus) must be
present and above the limits before the fuel is labeled “off-spec”.
There are major improvements in ISO 8217:2010 for distillates as well. The
introduction of a minimum viscosity limit is one, as operating large bore engines on
fuels with too low viscosity can be problematic. In the worst cases, the engine
may fail to start. Lastly, parameters addressing lubricity and oxidation stability, including a ‘de minimis’ limit on Fatty Acid Methyl Esters (FAME) in bright and clear distillates, have been added to ISO 8217:2010. Although FAME has good ignition and lubricity
properties, an elevated level may cause various operational problems during fuel
storage and handling. In short, ship operators should consider
switching to ISO 8217:2010 because this new standard gives vessels better protection
against the global trend of increasing volatility in bunker quality.
One significant development the shipping community should be aware of is that from 1
July 2012, the Maritime and Port Authority of Singapore will make it mandatory for all
bunker suppliers in Singapore to have products compliant with ISO 8217:2010
available for sale. With the world’s biggest bunkering port adopting ISO 8217:2010 as
the default bunker specification, other refueling hubs will likely follow suit. This
should then ease the availability of ISO 8217:2010-compliant supplies.

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Written by: Md Harun Ar Rashid , Technical Manager at DNVPS Singapore. (21st Batch)
Email: Harun.Rashid@dnvps.com.
Published in : The Voice of Asian Shipping,20 April 2012