What is VLSFO?
VLSFO stands for Very Low Sulfur Fuel Oil. It is a category of marine bunker fuel with a maximum sulfur content of 0.50% mass/mass, used as the primary IMO 2020 compliant fuel for ocean-going vessels. VLSFO sits between traditional heavy fuel oil (HSFO, up to 3.5% sulfur) and marine gas oil (MGO, max 0.10% sulfur) in terms of both sulfur content and cost.
VLSFO is typically a blended product — refiners and bunker suppliers combine residual and distillate components to produce a fuel meeting the 0.5% sulfur limit while maintaining acceptable viscosity (typically 380–500 cSt at 50 °C) and other ISO 8217 parameters. The exact blend composition varies by refinery and region.
On a global basis, VLSFO became the dominant marine fuel grade after 1 January 2020, when the IMO 2020 regulation took effect. It is traded through major bunkering and execution hubs rather than through a single export port. ALGHAF MARINE FZCO supply is not limited to one origin or loading point: execution may be structured through UAE / Fujairah, ARA, Mediterranean · Egypt, Southeast Asia / OPL, Black Sea or other approved transaction-specific locations.
VLSFO specifications and typical properties
VLSFO is a performance category, not one fixed ISO grade with a single universal set of numbers. The table below restates the contractual / typical references already used on this page. The applicable residual table and extra limits are those written in the SPA and cargo CoA.
| Property | Typical / contractual reference | Why it matters |
|---|---|---|
| Sulfur | 0.50% m/m max | IMO 2020 compliance outside ECAs |
| Density @ 15°C | 991.0 kg/m³ max | Quantity and handling |
| Kinematic viscosity @ 50°C | 380 cSt (RMG 380) or 500 cSt (RMG 500); some blends 180 cSt | Heating and injection |
| Flash point | 60 °C min | Safety |
| Pour point | 30 °C max (summer) / 0 °C max (winter) | Storage and handling |
| Water | 0.50% v/v max | Combustion and treatment |
| Ash | 0.10% m/m max | Deposits |
| Al + Si | 60 mg/kg max | Catalytic fines |
| Vanadium | 350 mg/kg max | High-temperature corrosion |
| Carbon residue | 18% m/m max | Combustion residue |
| CCAI | Typically < 870 for VLSFO on this page | Ignition quality |
| Sediment / stability | No single ISO number on this page — blend compatibility before mixing (ASTM D7112) | Sludge and filter risk |
See current supply terms, hubs and commercial availability → VLSFO supplier and commercial availability.
VLSFO sulfur limit and IMO 2020
The IMO 2020 regulation — formally known as MARPOL Annex VI, Regulation 14 — took effect on 1 January 2020. It reduced the global limit for sulfur in marine fuels from 3.50% to 0.50% mass/mass. In designated Emission Control Areas (ECAs) — including the Baltic Sea, North Sea, North American coast and US Caribbean — the limit is even stricter at 0.10%.
The rationale is environmental: sulfur dioxide (SO₂) emissions from ships contribute to acid rain, respiratory health problems in coastal populations, and particulate matter pollution in port cities. The IMO estimates the regulation prevents over 570,000 premature deaths annually.
To comply with IMO 2020, ship operators had three main options:
- Switch to VLSFO — burn compliant low-sulfur fuel with max 0.50% sulfur. The most common solution adopted by the industry.
- Install exhaust gas scrubbers (EGS) — continue burning cheaper HSFO but capture sulfur in the scrubber before emission. Capital-intensive upfront but can pay back in fuel cost savings.
- Switch to LNG (liquefied natural gas) — new-build vessels designed for LNG propulsion. A long-term solution with near-zero sulfur emissions.
The majority of the global fleet chose VLSFO as the path of least resistance, driving a dramatic restructuring of the marine fuel market from late 2019 through 2020.
VLSFO density, viscosity and flash point
Density
Density at 15 °C is stated here as 991.0 kg/m³ maximum. That is an ISO 8217 limit used on this page, not a typical cargo density. Actual density is on the CoA and is used for quantity and handling.
Viscosity
Kinematic viscosity at 50 °C is typically 380–500 cSt. Many programmes are classified as RMG 380 (380 cSt) or RMG 500 (500 cSt); some blends are 180 cSt. Viscosity drives heating and injection: standard VLSFO at 380 cSt requires preheating to approximately 100–120 °C for atomisation.
Flash point
Flash point is stated here as 60 °C minimum. The contractual flash point is the CoA value. It is a safety limit, not a performance target.
ISO 8217:2024 requirements for VLSFO
Marine residual and distillate fuels are specified under ISO 8217. The current published edition is ISO 8217:2024. That edition covers residual fuels with sulfur ≤ 0.50% m/m as a category — it does not make VLSFO a single SKU with one universal row of numbers.
Commercial parcels are still bought against the viscosity grade and extra limits in the SPA (for example RMG 380 or RMG 500) and confirmed on the cargo CoA. The property table above is the reference set already used on this page; it is not a substitute for the contracted ISO table.
VLSFO stability and compatibility
One of the key challenges with VLSFO is that, unlike the relatively homogeneous HSFO market of the pre-2020 era, VLSFO blends vary significantly by supplier and port. This creates two related risks:
Stability
Some VLSFO blends — particularly those with high aromatic content combined with paraffinic components — can be unstable and develop sludge or asphaltene precipitation in fuel tanks. This can clog filters and purifiers, damaging fuel system components. Buyers and ship operators should request a CCAI (Calculated Carbon Aromaticity Index) value and verify it is within acceptable limits (typically CCAI < 870 for VLSFO).
Compatibility
Mixing VLSFO from different suppliers can cause incompatibility — two individually stable fuels may destabilise when combined. Before topping up tanks, operators should check that the new VLSFO delivery is compatible with the remaining fuel using the ASTM D7112 blend compatibility test or by requesting blend compatibility certificates from the supplier.
We supply VLSFO with full CoA and quality certificates, and can provide CCAI data. Contact us before placing an order if you have specific stability requirements for your vessel or route.
VLSFO vs HSFO and MGO
| Parameter | HSFO (High Sulfur FO) | VLSFO (0.5% S) | MGO (Marine Gas Oil) |
|---|---|---|---|
| Max sulfur | 3.50% | 0.50% | 0.10% |
| IMO 2020 compliance | Only with scrubber | Yes (open sea) | Yes (all zones) |
| Viscosity (cSt at 50°C) | 380–700 | 380–500 | 1.5–11 (distillate) |
| ISO 8217 grade | RMG 380 / RMF 180 | RMG 380 (0.5%S blend) | DMB / DMA |
| Typical use | Deep sea (with EGS) | Deep sea (no EGS) | ECA zones, auxiliary engines |
| Relative cost | Lowest | Medium | Highest |
| Energy content | ~40.5 MJ/kg | ~40.2 MJ/kg | ~42.7 MJ/kg |
VLSFO offers a cost advantage over MGO of typically USD 80–150/MT depending on market conditions, making it the preferred IMO 2020 solution for most vessel operators on international routes. HSFO remains cheaper but requires scrubber investment (~USD 2–5 million per vessel).
Origin, blending and bunker quality
ALGHAF MARINE FZCO can offer VLSFO from non-sanctioned origins for selected destinations and cargo programs. Final origin, loading or STS location and supply route are transaction-specific and are confirmed in the applicable commercial and cargo documentation.
Loading or bunkering location does not by itself determine product origin. Depending on allocation, execution may be structured through UAE / Fujairah, ARA, Mediterranean · Egypt, Southeast Asia / OPL, Black Sea or other approved transaction-specific locations.
Novorossiysk may be available for applicable Black Sea cargo programs but is not the exclusive loading point for VLSFO supplied by ALGHAF MARINE FZCO.
Blend composition varies by refinery and region. CoA, CCAI and compatibility checks belong with bunker quality, not with the loading-port label.
For current commercial terms, see VLSFO supplier and commercial availability.
FOB, CIF and STS supply
ALGHAF MARINE FZCO supplies VLSFO meeting IMO 2020 and ISO 8217 for international marine fuel transactions under FOB, CIF and STS terms. Supply is not limited to a single origin or loading port. Non-sanctioned origin options are available for selected cargo programs.
FOB — transaction-specific loading point
VLSFO may be offered FOB from the loading location available for the applicable cargo program. The confirmed port, laycan and operational requirements are stated in the commercial offer and SPA. This is not a fixed Novorossiysk-only structure.
CIF — nominated destination
CIF supply may be evaluated to the buyer’s nominated destination. Final pricing reflects product origin, specification, freight, insurance, cargo size, destination and shipment window.
STS — approved locations
STS execution may be available at approved locations subject to cargo allocation, vessel compatibility, operational approvals and contractual requirements.
To request a commercial indication, provide:
- Volume required (metric tons)
- Delivery basis (FOB, CIF or STS)
- Destination and shipment window or laycan
- Any specific ISO 8217 grade requirements or CCAI limits
- Buyer company details
IMO 2020 compliant VLSFO, ISO 8217. Non-sanctioned origin on selected programs. FOB, CIF and STS from 5,000 MT, subject to allocation.
FAQ
What is VLSFO?
VLSFO (Very Low Sulfur Fuel Oil) is a marine bunker fuel with a maximum sulfur content of 0.50% mass/mass, compliant with the IMO 2020 global sulfur cap. It is the most widely used IMO 2020 compliant fuel for ocean-going vessels that do not have exhaust gas scrubbers.
What does VLSFO stand for?
VLSFO stands for Very Low Sulfur Fuel Oil. In bunkering it means marine fuel with max 0.50% sulfur under IMO 2020 MARPOL Annex VI. It is also called 0.5% fuel oil, compliant bunkers or low sulfur residual fuel.
What is the sulfur limit for VLSFO?
The sulfur limit used for VLSFO on this page is 0.50% m/m, matching the IMO 2020 global cap outside Emission Control Areas. In ECAs the marine-fuel sulfur limit is 0.10%, which is why MGO or equivalent 0.10% fuel is used there rather than 0.50% VLSFO.
What is the typical density of VLSFO?
This page states density at 15 °C as 991.0 kg/m³ maximum under the ISO 8217 limits used here. Actual cargo density is on the CoA. VLSFO is a performance category, not one fixed density.
What is the typical viscosity of VLSFO?
VLSFO typically has a kinematic viscosity of 380 cSt at 50 °C (classified as RMG 380 under ISO 8217), though some blends are 180 cSt or 500 cSt. Viscosity determines onboard heating and injection. Standard VLSFO at 380 cSt requires preheating to approximately 100–120 °C for atomisation.
What is the flash point of VLSFO?
The minimum flash point stated on this page is 60 °C. The contractual flash point is the value on the cargo CoA.
What is the difference between VLSFO, HSFO and MGO?
HSFO has up to 3.5% sulfur and is IMO 2020 compliant only with a scrubber. VLSFO has max 0.50% sulfur and is the usual open-sea compliant residual option. MGO has max 0.10% sulfur and is required in ECAs. VLSFO viscosity is typically 380–500 cSt at 50 °C; MGO is a distillate (about 1.5–11 cSt).
Which ISO 8217 standard applies to VLSFO?
The current published marine-fuel specification is ISO 8217:2024. Commercial VLSFO is not one universal ISO grade: the applicable residual table, viscosity grade (for example RMG 380 or RMG 500) and extra limits are those written in the SPA and cargo CoA.
Alghaf Marine FZCO — petroleum products export. This article is for informational purposes. Pricing and commercial terms are provided upon request. © 2026 Alghaf Marine FZCO.