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Fuel Testing

Singapore: CTI-Maritec shares key guidelines and pre-emptive measures on bio bunker fuel testing

Firm released a newsletter detailing key guidelines recently adopted on biofuel testing regulatory requirements and suggested key pre-emptive measures when testing marine biofuel.




RESIZED Hans Reniers on Unsplash

Bunker fuel testing and marine surveying business Maritec Pte Ltd (CTI-Maritec) on Monday (6 May) released a newsletter detailing key guidelines recently adopted on biofuel testing regulatory requirements and further suggested key pre-emptive measures that should be paid special attention to when testing biofuel:

Owing to several influencing factors, mainly stemming from concentrated efforts towards achieving crucial sustainability and decarbonization goals, the use of BioFuels is gaining swift momentum as a transitional fuel in the Maritime industry.

The advantages of BioFuels as a promising transitional fuel for vessels, in particular biodiesel blends, are that they can be used as drop-in fuel without modification of existing marine diesel engines and the Fatty Acid Methyl Esters (FAMEs), a primary component, do not emit Sulfur Oxides (SOx) during their combustion.

Over the last few years, regulatory bodies have also determinedly progressed on building viable frameworks and guiding principles on robust compliance requirements, implementation of transparent and functional processes, and setting in place definitive best practices to support the Maritime world in their decarbonisation journey.

Namely, in July 2023 at the 80th session of the Marine Environment Protection Committee (MEPC 80) IMO adopted the 2023 IMO Strategy on Reduction of GHG Emissions from Ships, with enhanced targets to tackle harmful emissions. The 2023 IMO GHG Strategy envisages, in particular, a reduction in carbon intensity of international shipping (to reduce CO2 emissions per transport work), as an average across international shipping, by at least 40% by 2030, compared to 2008. The 2023 IMO GHG Strategy also includes a new level of ambition relating to the uptake of zero or near-zero GHG emission technologies, fuels and/or energy sources which are to represent at least 5% (striving for 10%) of the energy used by international shipping by 2030.

Furthermore, the soon to be released (expected in the 2nd quarter of 2024) latest edition of ISO 8217:2024, is foreseen to have substantial inclusions of updated parameters for BioFuel testing.

All the above-mentioned advancements towards adopting procedures and means to bring about tangible change are reflective of the inevitable paradigm shift (we can, in truth, already observe taking place) in fuel usage and energy sources in the Maritime landscape. Yes, it will require significant commitment towards investment in scale-ups, however, one can almost be assured that major change will come sooner than we realise and this will mean having to effectively manage a vessel’s fuel quality testing requirements in a new light.


A comprehensive analysis of a BioFuel sample as per ISO 8217 will test its compositional makeup and characterization, as well as assessing its overall quality. It should also determine the presence and concentration of contaminants like ash, strong acids, organic chlorides and others, which can compromise the performance of the fuel.

Key pre-emptive measures and parameters from a commercial, environmental and operational point of view, which should be paid special attention to when testing BioFuel are summarised below:

  • FAME Content: FAME is more costly when compared to conventional bunker fuel. When ordering biodiesel blends, the FAME content is agreed between buyer and seller, from commercial & environmental (emission benefits) point of view, it is important to measure the FAME content in order to ensure that the correct FAME content is received as per the biodiesel blend transaction.
  • Net Heat of Combustion or Energy Content: Biodiesel blends have lower energy content when compared to conventional fossil fuels and the calculated net specific energy commonly used for fossil fuels may not apply to biodiesel blends. From an operational point of view in order to plan for the consumption of biodiesel blends for a voyage and to determine the engine’s performance accurately, lower calorific value (or net heat of combustion) shall be measured.
  • Oxidation Stability & Long-term Storage Stability: FAME oxidizes readily to form precipitates, which can clog filters, while increased acidity from oxidized fuel can foul injectors.
  • Low Temperature Operation: FAME has a higher cloud point when compared to petroleum diesel which can potentially cause wax formation at lower temperature leading to filter clogging.
  • Microbial Growth: FAME has great affinity for water to form stable emulsion. FAME and water emulsion (fuel haziness) can generate microbiological growth which leads to excessive formation of sludge that can clog filters and affect engine performance.
  • Corrosion: Microbial growth can produce Sulphide Reducing Bacteria (SRB) causing corrosion of steel tanks. Water can promote hydrolytic reactions, breaking down the FAME to form free fatty acids. Such species are corrosive and may attack exposed metal surfaces.
  • Deleterious Materials: Impurities such as free fatty acids, monoglycerides & glycerol (derived from low grades FAMEs used to blend biofuels), chlorinated organic compounds and other deleterious materials when present can pose detrimental effect on machineries and engine performance.

In view of the potential operation risks mentioned above (more likely in the case of BioFuels due to their composition make-up), it is advised that vessel owners should pre-emptively conduct additional analysis when routine ISO 8217 analysis indicates elevated values for some critical parameters.

The additional analysis should mainly be aimed at closely monitoring aspects and properties related to oxidative stability & long-term storage stability, low temperature operation, microbial growth, corrosive effects, deleterious materials and others.

Related: Singapore: CTI-Maritec publishes whitepaper on upcoming mandatory enhanced bunker fuel tests


Photo credit: Hans Reniers on Unsplash
Published: 7 May 2024

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Bunker Alerts

Bunker Flash: High cat fines found in ARA bunker fuel samples, alerts CTI-Maritec

Out of 22 samples representing both HSFO and VLSFO deliveries in ARA, CTI-Maritec found Aluminium and Silicon concentrations in two samples to be above 100 mg/Kg and in one sample at 68 mg/Kg level.





RESIZED Hans Reniers on Unsplash

Bunker fuel testing and marine surveying business Maritec Pte Ltd (CTI-Maritec) on Friday (12 July) issued an alert regarding high levels of Aluminium and Silicon (Al+Si) concentrations — referred to as catalytic (cat) fines —found after testing multiple samples from various bunker deliveries from the ARA region:

Findings & Insights:

From the period of 08 May 2024 to 05 July 2024, Maritec Pte Ltd (hereafter referred to as CTI-Maritec) tested twenty-two samples representing both HSFO and VLSFO deliveries from various suppliers in the Amsterdam-Rotterdam-Antwerp (ARA) region, which showed Aluminium and Silicon (Al+Si) concentrations ranging from 40 mg/Kg up to 177 mg/kg.

Out of the twenty-two samples, CTI-Maritec found Aluminium and Silicon (Al+Si) concentrations in two samples to be above 100 mg/Kg and in one sample at 68 mg/Kg level.

While the rest of the samples fell within the specifications of ISO8217:2005 (80 ppm) and even within the ISO8217:2010/2017 specification (including permitted limits of 72 PPM as per ISO4259 for a single test result), the Cat fines content were still considered at high levels. Many of these samples were also found to have high density, high TSP and high CCAI.

Aluminium and Silicon are main classes of abrasive solids found in fuels. High levels of abrasive particles at the engine inlet may lead to abnormal wear and tear of the fuel system components, piston rings and cylinder liners. To control the maximum amount of catalyst fines delivered to the engine, many engine builders specify a maximum limit of 15 mg/kg of Aluminium plus Silicon at engine inlet.

An efficiently operating fuel purification system is the main way of removing these particles. Measuring the fuel’s Aluminium and Silicon concentrations before and after centrifuge provides an indication of the efficiency of the system in removing catalyst fines.

Due to relatively high TSP, fuels might generate increased sludge formation, especially at the Purifiers and filters. Due to high CCAI, fuels might have ignition and combustion related issues.

Our Recommendations:

CTI-Maritec recommends collecting samples from within the fuel system at points such as the fuel oil tank transfer pump, before and after centrifuge, service tank and after filter samples to check the fuel cleaning efficiency.

This document, however, does not reflect on the overall quality of fuel being supplied in ARA region, if you intend to bunker at this region please request for a Certificate of Quality prior to loading.


Photo credit: Hans Reniers on Unsplash
Published: 15 July 2024

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Fuel Quality

FOBAS: CIMAC publishes more documents on ISO 8217:2024 marine fuel specs

FOBAS has highlighted that CIMAC WG7 (Fuels) has released several documents including on diesel engines to support the adoption of ISO 8217:2024 marine fuel standard.





Louis Reed from Unsplash

Lloyd’s Register Fuel Oil Bunkering Analysis and Advisory Service (FOBAS) on Friday (5 July) released a bulletin to highlight that CIMAC WG7 (Fuels) has released more documents to support the adoption of ISO 8217:2024 marine fuel standard:

Further to our last bulletin, please note that CIMAC WG7 (Fuels) has released a very comprehensive document titled Design and operation of fuel cleaning systems for diesel engines

This document has three sections, first part discusses the properties of conventional fuels, second part reviews the corresponding fuel system designs, and third part provides best practice approach to handling marine fuels onboard.

Similarly, CIMAC has also published a guidance document titled The interpretation of marine fuel analysis test results which is effectively a revision of the CIMAC WG7 guideline No. 02:2016. 

The document provides information on how to apply the ISO 4259 approach to the interpretation of the analysis test results in respect of the marine fuel characteristics given in ISO 8217 from both the recipient and the supplier perspectives. This revision includes tests added in ISO 8217:2024 and incorporates updated method precision data where relevant.

Moreover, CIMAC has published important guidance titled Overview and interpretation of total sediment test results in the context of ISO 8217:2024

This document provides an overview of test methodologies for assessing stability and cleanliness of residual marine fuels through the interpretation of the accelerated total sediment (TSA), potential total sediment (TSP) and existent total sediment (TSE) test results.

We hope you will find these documents useful. Please note that FOBAS experts are an integral part of CIMAC WG7 who along with other members, worked extensively to produce these guidance documents.

Related: CIMAC Working Group Fuels publishes first of five guidelines supporting release of ISO 8217:2024
Related: FOBAS highlights publication of CIMAC biofuel guidance document
Related: FOBAS announces publication of ISO 8217:2024 marine fuel specifications and FAQs
Related: VPS shares review and position on new ISO 8217:2024 marine fuel specs


Photo credit: Louis Reed from Unsplash
Published: 8 July, 2024

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Bunker Fuel

VPS shares review and position on new ISO 8217:2024 marine fuel specs

VPS believes new revised standard ISO8217:2024 is a major step forward from the previous 2017 6th revision and will provide global shipping and bunker industry with greater support than its predecessor.






Steve Bee, Group Commercial Director of marine fuels testing company VPS, on Thursday (4 July) highlighted on the latest ISO 8217:2024 revisions and their impact on maritime emissions compliance:

Ever-increasing environmental legislation in relation to reducing emissions from the global maritime fleet, has driven the development of numerous new fuels, since the last revision of the international marine fuel standard, ISO 8217:2017. 

We have seen in recent years the introduction of Very Low Sulphur Fuel Oils (VLSFOs) to support meeting the IMO2020 change in reducing the global cap for sulphur levels within marine fuels to 0.50%. This has been followed by a transition to include synthetic, renewable and recycled content within marine fuels, in the form of biofuels. These will support the reduction of carbon dioxide emissions to help comply with the IMO 2030/2050 targets and numerous other legislative requirements such as, Monitoring, Recording & Verification (MRV), CII & EEXI, EU Emissions Trading Scheme and FuelEU Maritime.

As the world’s leading marine fuel testing company, VPS has over the years witnessed a slow uptake of new revisions of the ISO 8217 standard, due to a combination of price and initial availability.

According to our most recent data, 12.6% of fuel samples that are received for testing were purchased in accordance with the 2005 standard, 47.7% with the 2010 revision, 19.3% with the 2012 version, and just 20.4% with the most recent revision published in 2017.

VPS shares review and position on new ISO 8217:2024 marine fuel specs

Testing to a standard specification which is almost 20 years old and superseded by four revisions, the 2005 revision offers little in the way of vessel and environmental protection with respect to modern fuels, yet over 12% of fuels are still purchased against this revision. The cat-fine limit of 80ppm, has elevated risk of vessel damages than the 60ppm limit introduced as far back as 2010. Sulphur limits are widely outdated with the requirements of the IMO2020, 0.50% limit, stating sulphur limits of 3.50%, 4.00% and 4.50%, for the various residual grades, offering little in regard to today’s SOx regulations. In addition, Clause 5 of ISO 8217:2005, offers no consideration of today’s more complex fuel mix and the presence of FAME, HVO, GTL, or BTL in today’s fuel supply chain.

Today, the most popular revision of the standard is still ISO 8217:2010, accounting for almost 50% of all fuel samples received for testing. This 14-year old fuel standard, pre-empted the future changes in sulphur limit regulations, by removing sulphur limits from Table 2. However, this old standard revision did not account for the statutory requirements of IMO2020 and the introduction ten years later, of the 0.50% sulphur VLSFO fuels which came to the market to address the legislative reduction in SOx emissions from global shipping. There is no specification within this revision for VLSFOs, currently the most popular marine fuel type purchased today. 

In addition, for VLSFOs there has been a reduction in the spread of viscosity range from 2021 to 2024. In 2021 the majority (37%) of the VLSFO’s supplied in the marine industry had a viscosity in the range of 80 to 100 cSt. This has changed over the years showing an increasing trend in the viscosity, so that in 2024 we see an increase to 43% of the VLSFO’s supplied in the marine industry with viscosity in the range of 80 to 100 cSt. 

However, all samples are tested to a 380Cst specification, with only a maximum viscosity specification and no minimum viscosity limit, which would have been extremely helpful especially to the operators to plan ahead. Yet, a positive introduction was the Cat-fine limit reduction to 60ppm.

For distillate grades, ISO 8217:2010 introduced a new grade, DMZ, with minimum viscosity 3.000 mm2/s at 40°C. Specification limits were added for hydrogen sulphide, acid number, oxidation stability and lubricity. In addition, the minimum viscosity requirement for DMA was raised to 2.000 mm2/s and a minimum viscosity requirement of 2.000 mm2/s added for DMB.

Some changes were also made to the residual grades.

Yet Clause 5 within ISO8217:2010, has the following statement: 

5.4 The fuel shall be free from bio-derived materials other than 'de minimis' levels of FAME (FAME shall be in accordance with the requirements of EN 14214 or ASTM D6751). In the context of this International Standard, “de minimis” means an amount that does not render the fuel unacceptable for use in marine applications. The blending of FAME shall not be allowed.

The ISO 8217:2017 revision currently accounts for only 20% of fuels purchased, which is astonishingly low, considering that up to May 2024, it was the most recent revision? This revision did move nearer than its predecessors towards accounting for the presence of renewable feedstocks and FAME.

This sixth revision had changes in the general requirements to allow hydrocarbons from co-processing of renewable feedstock with petroleum feedstock and hydrocarbons from synthetic or renewable sources. Additional marine distillate grades, DFA, DFZ and DFB were added with a maximum fatty acid methyl ester(s) (FAME) content of 7.0 volume % 

Requirements to report cloud point and cold filter plugging point were added to winter grades of DMA and DMZ, whilst the sulphur content of DMA and DMZ was reduced to a maximum of 1.00 mass % and the sulphur content of DMB reduced to a maximum of 1.50 mass %. Along with these changes, the “de minimis” FAME level was increased to approximately 0.5%.

Finally, Clause 5 contained the following statement:

5.1 The fuel composition shall consist predominantly of hydrocarbons primarily derived from petroleum sources while it may also contain hydrocarbons from the following:

- synthetic or renewable sources such as Hydrotreated Vegetable Oil (HVO), Gas to Liquid (GTL) or Biomass to Liquid (BTL);

- co-processing of renewable feedstock at refineries with petroleum feedstock.

Therefore, whilst upon release, each revision of ISO8217 has introduced many improvements relating to marine fuel quality at the time of release, the drive to reduce emissions from global shipping has seen many changes in fuels, introduced at a faster rate than the updates within ISO8217. As a consequence,

buying fuels to older revisions, will only elevate the levels of risk to a vessel, crew health & safety and the environment. So, in May 2024, 80% of marine fuels are still being purchased to ISO82217 revisions which are between 12-19 years old, bearing little resemblance to the fuels available in today’s marine fuel market.

The introduction of the latest and 7th revision of the standard, ISO 8217:2024, released on 30th May 2024, has now addressed a number of the requirements associated with these newer fuels, to support the industry on its decarbonisation journey.

In addition to ISO 8217:2024, ISO 8216:2024, released prior to the release of ISO 8217:2024, identifies the various fuel grades introduced within the new standard and explaining the designated fuel codes.

VPS Review of ISO8217:2024

VPS believes the new revised standard ISO 8217:2024, is a major step forward from the previous 2017 6th revision and will provide global shipping and the bunker industry with greater support than its predecessor. Further to this, VPS would like to provide additional fuel quality and fuel management considerations:

Table 1 and Table 3 emphasises on distillates and biofuels with residual and distillate blends including FAME, HVO, GTL and BTL. VPS have tested several biofuels over the recent years with different bio-components, such as Cashew Nut shell Liquid (CNSL) and Tyre Pyrolysis Oil (TPO), Bio FAME residues, Algae oil all of which exhibit different behaviours and fuel management challenges, to those vessels choosing to use such fuel blends. Some of the key parameters that are required to identify the quality of such fuels are not considered in this revision of the standard.

Note: The full article by VPS’ Steve Bee and tables mentioned can be found here

Related: Integr8 report: Two-thirds of residual bunker fuels still sold with pre-2017 ISO specs
Related: CIMAC Working Group Fuels publishes first of five guidelines supporting release of ISO 8217:2024
Related: Singapore: CTI-Maritec outlines key changes of newly released ISO 8217:2024
Related: FOBAS announces publication of ISO 8217:2024 marine fuel specifications and FAQs
Related: FOBAS issues industry update of new ISO 8217:2024 marine fuel specifications


Photo credit: VPS
Published: 5 July, 2024

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