Diesel
A grade letter is a temperature promise.
Automotive diesel to EN 590 — 10 mg/kg sulphur, cetane 51 minimum, up to 7 % FAME — quoted against the cold-flow grade the discharge market will actually see, because that letter is the parameter that strands cargoes.
The desk
"EN 590, 10 ppm" describes about a third of the contract.
Diesel is the most standardised product on our book, which makes it the one most often bought carelessly. A buyer names EN 590 and a sulphur figure, both sides feel the specification is settled, and neither has yet said anything about the two parameters that decide whether the cargo works.
The first is cold flow. EN 590 does not set one cold-filter plugging point; it sets six temperate grades and five arctic classes, from +5 °C down to −44 °C. Which one applies is a matter of country and season, and a grade that is correct in Rotterdam in September is a gelled tank in the Baltic in January.
The second is FAME. Up to 7 % v/v is permitted, and biodiesel changes the fuel's oxidation stability, its water behaviour and its microbial susceptibility. A B7 parcel and a FAME-free parcel are not the same product in storage, however identically they certify on the day of loading.
So we quote the grade letter, the FAME content and the stability position with the sulphur number, not after it.
The standard
EN 590, parameter by parameter.
The European automotive diesel specification. As with every standard we quote against, the edition belongs in the contract — the FAME and stability provisions in particular have moved across revisions.
| Parameter | Limit | What it governs |
|---|---|---|
| Cetane number | 51.0 min | Ignition delay, cold starting, combustion noise and emissions. The quality headline. |
| Cetane index | 46 min | Calculated from density and distillation. Specified alongside cetane number to catch a parcel whose measured cetane has been lifted by additive rather than by composition. |
| Density at 15 °C | 845.0 kg/m³ max | Energy content per litre and injection metering. Also the parameter that quietly limits how much paraffinic material a blend can carry. |
| Sulphur | 10 mg/kg max | Aftertreatment protection. A binary compliance line. |
| FAME content | 7.0 % v/v max | The B7 ceiling. See below — it changes the fuel's behaviour in storage. |
| Flash point | above 55 °C | Safety in handling and storage, and a marker of light-end contamination if it fails. |
| Viscosity at 40 °C | 2.000–4.500 mm²/s | Injection system lubrication and spray formation, bounded at both ends. |
| Polycyclic aromatics | 8.0 % m/m max | Particulate emissions. Constrains how much cracked material is in the blend. |
| Water | 200 mg/kg max | Corrosion, injector damage and microbial growth. Tighter in practice on FAME-bearing fuel. |
| Total contamination | 24 mg/kg max | Particulates that block filters. The parameter that catches a dirty tank. |
| Lubricity, HFRR wear scar at 60 °C | 460 µm max | Fuel pump and injector wear. Deep desulphurisation strips natural lubricity, so this is an additive-dependent parameter — and one worth testing rather than assuming. |
| Oxidation stability | Specified where FAME exceeds 2.0 % v/v | Shelf life. The provision exists precisely because biodiesel content changes it. |
| Distillation | 65 % recovered at 250 °C max; 85 % at 350 °C min; 95 % at 360 °C max | Boiling range, held at both ends. Feeds the cetane index and bounds the heavy tail. |
Cold flow
Six temperate grades, five arctic classes.
The part of EN 590 that is not one specification but eleven. Cold-filter plugging point is the operative number: the temperature at which wax begins to block a filter, which is where a diesel actually fails in service.
| Temperate grade | A | B | C | D | E | F |
|---|---|---|---|---|---|---|
| CFPP max (°C) | +5 | 0 | −5 | −10 | −15 | −20 |
| Arctic class | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| CFPP max (°C) | −20 | −26 | −32 | −38 | −44 |
| Cloud point max (°C) | −10 | −16 | −22 | −28 | −34 |
Cetane
Number and index, and why both are specified.
Cetane number is measured in an engine. Cetane index is calculated from density and distillation. EN 590 requires both, and the reason is worth understanding before you accept a certificate.
Cetane improver additive — typically 2-ethylhexyl nitrate — raises measured cetane number without changing the fuel's composition. It is a legitimate and widely used tool. But it does not raise the cetane index, because the index is derived from properties the additive does not move.
So the gap between number and index is informative: a fuel comfortably above both has genuine ignition quality, while one that passes on number and sits at the index floor has been additised to get there. Neither is wrong. They behave differently in a cold engine, and only one of them is visible if you read only the cetane number.
What we do about it. We report both, always, and we state whether a parcel is additised. If a buyer's own blending will dilute the additive, the index is the better predictor of where they will land, and we say so at enquiry rather than leaving them to discover it.
The same logic runs through this page: EN 590 pairs a measured parameter with a calculated or compositional one in several places, and each pairing exists because someone once passed the first while failing the intent.
FAME
B7 is not conventional diesel with a rounding error.
Up to 7 % v/v fatty acid methyl ester is permitted, and most European pump diesel carries it. The specification consequences are modest; the storage and logistics consequences are not.
| What changes | Why it matters to a cargo |
|---|---|
| Oxidation stability | FAME oxidises faster than mineral diesel, forming acids and sediment. EN 590 imposes an oxidation stability requirement specifically above 2.0 % FAME. On a long voyage or into slow-turning tankage, this is the parameter to hold rather than assume. |
| Water affinity | FAME is hygroscopic relative to mineral diesel and holds more dissolved water. Free water at a tank bottom then becomes an interface where things grow. |
| Microbial growth | The classic "diesel bug". Water plus FAME plus a warm tank is a viable habitat, and the result blocks filters and corrodes tank floors. It is a housekeeping problem created by a fuel property. |
| Cold flow | FAME has its own cold-flow behaviour and its own cloud point contribution. A B7 blend's cold-flow performance is not simply the base fuel's. |
| Material compatibility | FAME is a mild solvent toward some elastomers and coatings, and it lifts deposits from tanks previously in mineral-only service — which arrive at the filter as the first symptom. |
Paraffinic diesel
HVO and XTL sit under a different standard.
Hydrotreated vegetable oil and other synthetic paraffinic diesels are not FAME and are not covered by the FAME provisions of EN 590. They have their own European specification, EN 15940, for paraffinic diesel fuel.
The distinction is commercially important and frequently blurred. HVO is a hydrocarbon: it does not oxidise like FAME, it does not carry FAME's water and microbial behaviour, and it has very high cetane and very low aromatics. What it also has is low density — typically below the EN 590 minimum — which is why neat HVO is sold to EN 15940 rather than as EN 590 diesel, and why it can only be blended into an EN 590 pool up to the point where density still holds.
So "renewable diesel" in an enquiry needs unpacking before it can be priced: FAME blended to B7 under EN 590, or paraffinic HVO under EN 15940, or HVO as a blend component into a conventional pool. Three different products, three different specifications, three different prices. We ask which, and where a sustainability claim is attached we handle the certification through certified co-processed components rather than asserting it on the cargo.
Supply
What we supply.
EN 590 ULSD, 10 mg/kg
The core grade, in the temperate grade or arctic class the destination requires, B0 or up to B7 as specified.
Higher sulphur tiers for export markets
Where the destination's own standard permits it. Quoted to that standard by name, never as "EN 590 equivalent" — a phrase we do not use, because it means nothing.
Parcels and basis
Clean-product tankers into a buyer's terminal, FOB, CFR, CIF or delivered. Term programmes with monthly liftings where a market wants continuity.
Scope
Where our obligation ends.
- What we supply
- Cargo parcels into terminals and shore tankage, with independent inspection and the full certificate.
- What we do not do
- We are not a retail or forecourt supplier, we do not operate blending or additive terminals, and we do not deliver into vehicles or into ships — for marine grades see Marine Fuels.
- Additive and cold-flow treatment
- We will state whether a parcel is additised, for cold flow and for lubricity. Dosing at the receiving terminal is your operation, and a fuel additised to a CFPP is a different proposition from one that reaches it compositionally — we will tell you which you are getting.
- Duty and marking
- Excise treatment and fiscal marking are the buyer's, and they are what separate this product from gasoil. We will not supply automotive diesel into a marked-gas-oil application or the reverse.
How to specify
Six lines and we can price it.
The first two are the ones usually missing.
Cold-flow grade or class
The letter or the number, or simply tell us the discharge market and month and we will name it. Add a cloud point limit if your operation needs one.
FAME position
B0, B7, or a stated maximum — and the storage turn at your terminal, because that is what makes the answer matter.
Standard and edition
EN 590 with a year, or the destination's national standard by name. Not "EN 590 equivalent".
Cetane requirement
Whether you hold above the 51 minimum, and whether you want the index held above its floor as well.
Quantity, parcel size and basis
Tonnes or cubic metres, FOB / CFR / CIF / delivered, one cargo or a programme.
Terminal and tank history
Receiving tankage, and whether it has been in FAME-bearing or mineral-only service. This decides more filter problems than the fuel does.
Quality
Every parameter, with its method named.
Independent inspection by an agency appointed for the cargo — SGS, Bureau Veritas or Intertek — instructed jointly, sampling under supervision at a point agreed in advance, with sealed retains at both ends and the determination points named in the contract.
- Core test set
- Cetane number and cetane index; density at 15 °C; sulphur; FAME content; flash point; viscosity at 40 °C; CFPP and cloud point; distillation; polycyclic aromatics; water; total contamination; HFRR lubricity; oxidation stability; ash; carbon residue; copper corrosion; appearance and colour.
- Reported as a pair, deliberately
- Cetane number with cetane index, and CFPP with cloud point. In both cases the second number tells you how the first was achieved.
- FAME-bearing parcels
- Oxidation stability, acid number and water, plus the FAME content by its own method rather than by declaration.
- Additive disclosure
- Whether cetane improver, cold-flow improver or lubricity additive has been dosed. Stated, not implied.
- Documentation per parcel
- Certificate of Quality, Certificate of Quantity, Certificate of Origin, safety data sheet in the destination language, bill of lading, three-cargo tank history and the independent inspection report.
Straight answer
What we will tell you before you ask.
- That the grade letter matters more than the sulphur figure
- Everyone specifies 10 ppm and almost nobody specifies the cold-flow grade. It is the parameter that strands cargoes, and it depends on where and when you discharge.
- That we do not use the phrase "EN 590 equivalent"
- A fuel either meets a named standard and edition or it meets a different one. "Equivalent" is where the argument starts.
- That cetane number alone can be flattering
- Additive raises the number and not the index. We report both and tell you whether a parcel is additised, because if you are blending it down the index is what predicts where you land.
- That B7 and B0 are different products in a slow tank
- Not on the certificate — in storage, over months. If your turn is slow or your tankage is warm, ask us for B0 and we will tell you honestly whether we can serve it.
- That HVO is not FAME and not EN 590
- It sits under EN 15940 and its density usually keeps it out of an EN 590 pool at high blend rates. Three different products get called "renewable diesel"; we will establish which one you mean before quoting.
- Where an origin cannot be cleared
- Screened per consignment; declined where it cannot be documented, and not referred onward — see Compliance.
Enquiries
Every enquiry is answered by the desk that handles it.
Send the product, quantity, delivery basis, destination and timing. We revert with availability, an indication and the documentation that accompanies it. Specifications are released once we know who we are speaking with.