⛽ Oxidation stability of diesel fuel
In short
Accelerated oxidation of middle-distillate petroleum fuels under specified conditions, after which the insolubles are determined — filterable and adherent to the glassware; the result provides a basis for estimating the storage stability of the fuel under the conditions of the test. The test is performed according to PN-EN ISO 12205:2011; Field of application: middle-distillate petroleum fuels without residual components and without significant non-petroleum components (clause 1). The procedure comprises 4 steps; it is used for: Diesel fuel — at most 25 g/m³, regardless of the FAME content (Journal of Laws 2024, item 1018, Annex 3 item 14), Paraffinic diesel fuel — at most 25 g/m³ (Journal of Laws 2025, item 426, Annex 3 item 13), Middle-distillate petroleum fuels with an initial boiling point above about 175 °C and a 90 % (V/V) recovery point below 370 °C — estimating storage stability under the conditions of the test (clause 1).
At a glance
- Standard: PN-EN ISO 12205:2011
- Category: Petrochemistry
- Procedure steps: 4
- Field of application: middle-distillate petroleum fuels without residual components and without significant non-petroleum components (clause 1)
- Quantity measured: insolubles: filterable and adherent (clause 1, definition 3.1)
- Requirement for diesel fuel: at most 25 g/m³ (Journal of Laws 2024, item 1018, Annex 3 item 14)
Overview
STATUS (as of 30.10.2026). PN-EN ISO 12205:2011 — Polish version, published 20.12.2013, implements EN ISO 12205:1996 and ISO 12205:1995 [IDT]; it replaced PN-ISO 12205:1997 and its Ap1:2002. The PKN catalogue card has no withdrawal note — the standard is current; Polish title according to the card: “Przetwory naftowe — Oznaczanie stabilności oksydacyjnej średnich destylatów paliwowych”. ISO 12205:1995 is the first edition.
SCOPE (clause 1). Procedure for measuring the inherent stability of middle-distillate petroleum fuels under accelerated oxidizing conditions. The standard does not apply to fuels containing residual components or any significant component from a non-petroleum source. It provides a basis for estimating — under the conditions of the test — the storage stability of distillates with an initial boiling point above about 175 °C and a 90 % (V/V) recovery point below 370 °C. The method may not predict the quantity of insolubles that will form in field storage — it depends on conditions too variable for the test to predict accurately. Oxidation is a chemical process causing adherent and filterable insolubles to form; substances that catalyse oxidation, such as copper or chromium, cause greater quantities of insolubles to form (Note 1). Adherent insolubles are material produced in the test that adheres to the glassware after the fuel has been flushed from the system (definition 3.1).
LEGAL REQUIREMENTS. Diesel fuel: oxidation stability at most 25 g/m³. The requirement according to PN-EN ISO 12205 applies regardless of the FAME content, and diesel fuel with more than 2.0 % (V/V) FAME must additionally have a stability of at least 20.0 h according to PN-EN 15751 or 60.0 min according to PN-EN 16091 (in disputes — PN-EN 15751) (Journal of Laws 2024, item 1018, Annex 3 items 14–15 and footnote 7). The same requirements apply to paraffinic diesel fuel (Journal of Laws 2025, item 426, Annex 3 item 13).
WHAT WE DO NOT GIVE HERE. The publicly available text of the standard covers only the foreword, scope, normative references and the first definition. We do not give the sample volume, ageing temperature and time, oxygen flow, filtration procedure, solvent for the adherent insolubles, calculation or precision. The American method ASTM D2274 on the same subject carries out the ageing at 95 °C; it also notes that it has not been validated for biodiesel and its blends, and that samples containing biodiesel can partially dissolve the membrane filter and give erroneous results.
Method principle
A sample of middle distillate is subjected to accelerated oxidation under conditions specified in the standard, after which the insolubles are determined: filterable — retained on filtration — and adherent, which remain on the glassware after the fuel has been flushed out (clause 1, definition 3.1). The result provides a basis for estimating the storage stability of the fuel under the conditions of the test, but does not predict the quantity of insolubles in actual storage.
Applications
- Diesel fuel — at most 25 g/m³, regardless of the FAME content (Journal of Laws 2024, item 1018, Annex 3 item 14)
- Paraffinic diesel fuel — at most 25 g/m³ (Journal of Laws 2025, item 426, Annex 3 item 13)
- Middle-distillate petroleum fuels with an initial boiling point above about 175 °C and a 90 % (V/V) recovery point below 370 °C — estimating storage stability under the conditions of the test (clause 1)
Key parameters
| Parameter | Value |
|---|---|
| Field of application | middle-distillate petroleum fuels without residual components and without significant non-petroleum components (clause 1) |
| Quantity measured | insolubles: filterable and adherent (clause 1, definition 3.1) |
| Requirement for diesel fuel | at most 25 g/m³ (Journal of Laws 2024, item 1018, Annex 3 item 14) |
| Additionally with FAME above 2.0 % (V/V) | at least 20.0 h (PN-EN 15751) or 60.0 min (PN-EN 16091); in disputes PN-EN 15751 (Annex 3 item 15) |
Standard
- Standard number
- PN-EN ISO 12205:2011
- Title (PL)
- Przetwory naftowe — Oznaczanie stabilności oksydacyjnej średnich destylatów paliwowych
- Title (EN)
- Petroleum products — Determination of the oxidation stability of middle-distillate fuels
Step-by-step procedure
-
Sampling
According to ISO 3170 or ISO 3171 (normative references, clause 2).
-
Ageing
The sample is oxidized under the accelerated conditions specified in the standard (clause 1).
-
Determining the insolubles
Filterable insolubles and insolubles adhering to the glassware after the fuel has been flushed from the system are determined (clause 1, definition 3.1).
-
Assessment
The result is compared with the requirement for the fuel concerned, e.g. at most 25 g/m³ for diesel fuel (Journal of Laws 2024, item 1018).
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Apparatus | for ageing the sample, filtering and weighing the insolubles — requirements are in clauses of the standard outside the publicly available text | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Reagents and water | — | reagents according to ISO 6353-2 and water according to ISO 3696 (normative references, clause 2); composition of the solvent for the adherent insolubles — outside the available text |
Health and safety (OHS)
- The standard warns that its use may involve hazardous materials, operations and equipment, and that the user establishes the safety and health practices (warning before clause 1)
- Fuel samples and reagents are handled according to their safety data sheets
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN ISO 12205:2011 — “Petroleum products — Determination of the oxidation stability of middle-distillate fuels”.
How does this method work?
A sample of middle distillate is subjected to accelerated oxidation under conditions specified in the standard, after which the insolubles are determined: filterable — retained on filtration — and adherent, which remain on the glassware after the fuel has been flushed out (clause 1, definition 3.1).
What is the measuring range and accuracy?
Field of application: middle-distillate petroleum fuels without residual components and without significant non-petroleum components (clause 1); Quantity measured: insolubles: filterable and adherent (clause 1, definition 3.1); Requirement for diesel fuel: at most 25 g/m³ (Journal of Laws 2024, item 1018, Annex 3 item 14); Additionally with FAME above 2.0 % (V/V): at least 20.0 h (PN-EN 15751) or 60.0 min (PN-EN 16091); in disputes PN-EN 15751 (Annex 3 item 15).
How long does the test take?
The procedure comprises 4 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Apparatus.
Where is this test used?
Diesel fuel — at most 25 g/m³, regardless of the FAME content (Journal of Laws 2024, item 1018, Annex 3 item 14); Paraffinic diesel fuel — at most 25 g/m³ (Journal of Laws 2025, item 426, Annex 3 item 13); Middle-distillate petroleum fuels with an initial boiling point above about 175 °C and a 90 % (V/V) recovery point below 370 °C — estimating storage stability under the conditions of the test (clause 1).
What safety precautions apply?
The standard warns that its use may involve hazardous materials, operations and equipment, and that the user establishes the safety and health practices (warning before clause 1); Fuel samples and reagents are handled according to their safety data sheets.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN ISO 12205.