⛽ Total contamination in diesel fuel

Petrochemistry PN-EN 12662

Overview

STATUS (as of 02.11.2026). PN-EN 12662-1:2024-11 — Polish version, published 02.01.2026, implements EN 12662-1:2024 [IDT]; it replaced PN-EN 12662:2014-05 (Polish and English versions). The PKN catalogue marks PN-EN 12662:2014-05 as withdrawn on 28.11.2024 and replaced by PN-EN 12662-1:2024-11 and PN-EN 12662-2:2024-11. Changes in EN 12662-1:2024 compared with EN 12662:2014 (foreword): the scope was split into two parts — Part 1 covers middle distillates and diesel fuels with up to 30 % (V/V) FAME, Part 2 neat FAME — and new precision data come from a new statistical analysis of the interlaboratory test data without FAME samples (according to EN ISO 4259-1:2017). According to the introduction of the standard, the changes made to the method in 2014 caused difficulties in laboratories when testing FAME, so the previous method was included as Part 1 and a separate Part 2 was developed for neat FAME.

SCOPE (clause 1). Determination of the content of undissolved substances, referred to as total contamination, in middle distillates and diesel fuels containing up to 30 % (V/V) FAME. The working range is from 12 mg/kg to 26 mg/kg and was established in an interlaboratory study according to EN ISO 4259-1. The standard applies in general to products with a kinematic viscosity not exceeding 8 mm²/s at 20 °C or 5 mm²/s at 40 °C. The method can also be used for paraffinic diesel fuels (EN 15940), diesel fuels with more than 30 % (V/V) FAME and petroleum products of higher viscosity, but the precision has not been determined for them. The introduction of the standard explains the purpose of the test: excessive contamination of a fuel system can cause premature blocking of filters or failure of system components.

HOW THE TEST PROCEEDS (clauses 4–9 according to the available text of EN 12662:2014 — Part 1 took over its method for middle distillates and diesel fuels, changing only the scope and the precision data). A weighed test portion is filtered under vacuum through a previously weighed filter; products with a kinematic viscosity above 8 mm²/s at 20 °C (5 mm²/s at 40 °C) are diluted with a solvent before filtration. The filter with the residue is washed, dried and weighed; the contamination is calculated from the difference in filter mass and expressed relative to the sample mass in mg/kg (clause 4). The filters are of the high-retention glass fibre type, 47 mm in diameter, with a mean pore size of 0.7 µm. Heptane (purity at least 99.0 % (V/V)) and xylene are filtered through a 0.45 µm membrane filter; the dilution solvent is 750 ml of heptane and 250 ml of xylene, and propan-2-ol is used to dry glassware after rinsing with water (clauses 5–6). The vacuum source maintains an absolute pressure of 2–5 kPa in the apparatus (which excludes a water vacuum pump); the oven is of the static type, without fan-assisted circulation, explosion-proof, set to (110 ± 5) °C; the analytical balance weighs to the nearest 0.1 mg (clause 6). Because the amounts measured are very small, the test is performed in a clean environment, and containers and apparatus are washed in turn with warm water containing detergent, warm water, water, propan-2-ol and heptane (clause 7). Samples are taken according to EN ISO 3170, EN ISO 3171 or EN 14275 into glass containers (brown or shielded from light), filled to 80–85 % of their capacity (clause 8). Before the test, the container with its closure loosened is heated in a water bath or oven at 40 °C for 30–60 min so that any separated components dissolve again, and after tightening the closure it is cooled to room temperature and washed on the outside with propan-2-ol (9.2.1–9.2.2).

LEGAL REQUIREMENTS. Diesel fuel: contamination content at most 24 mg/kg — both for “standard” diesel fuel and for diesel fuel “with improved low-temperature properties” (Regulation of the Minister of Climate and Environment of 26.06.2024 on quality requirements for liquid fuels, Journal of Laws 2024, item 1018, Annex 3 item 11). The regulation of the same day on test methods for the quality of liquid fuels (Journal of Laws 2024, item 1058, Annex Part II point 10) describes the method — filtration of a specified amount of sample under vacuum through a pre-weighed filter, washing, drying and weighing, result in mg/kg — and refers to PN-EN 12662, cited without a date, before the standard was split into two parts. The regulation on test methods for the quality of liquid biofuels (Journal of Laws 2025, item 1341) specifies the standard implementing EN 12662-1 for diesel fuel containing 20 % methyl ester and for paraffinic diesel fuel from bio-hydrocarbons (Part II point 11, Part III point 10), and EN 12662-2 for methyl ester used as a self-contained fuel (Part I point 16).

WHAT WE DO NOT GIVE HERE. Publicly available are the text of EN 12662:2014 up to 9.2.2 and, from Part 1, the foreword, introduction, scope and table of contents. We do not give the mass of the test portion, the filtration, washing and drying of the filter (clauses 10–11), the calculation formula, the rounding of the result or the precision values (clauses 12–14); Part 1 has new precision data, so values from earlier editions are not carried over.

Method principle

A weighed test portion is filtered under vacuum through a previously weighed glass fibre filter with a mean pore size of 0.7 µm. The undissolved substances retained on the filter under the test conditions are the total contamination (definition 3.1); the filter with the residue is washed, dried and weighed.

The contamination is calculated from the difference in filter mass before and after filtration and expressed relative to the sample mass in mg/kg. Products with a kinematic viscosity above 8 mm²/s at 20 °C or 5 mm²/s at 40 °C are diluted with a solvent before filtration (clause 4 according to the text of EN 12662:2014).

Applications

• Diesel fuel — contamination content at most 24 mg/kg (Journal of Laws 2024, item 1018, Annex 3 item 11); method according to Journal of Laws 2024, item 1058, Annex Part II point 10
• Middle distillates and diesel fuels containing up to 30 % (V/V) FAME — working range 12–26 mg/kg (clause 1)
• Paraffinic diesel fuels (EN 15940), diesel fuels with more than 30 % (V/V) FAME and products with a viscosity above 8 mm²/s at 20 °C — the method can be used, but the precision has not been determined (clause 1)
• Liquid biofuels: diesel fuel with 20 % methyl ester and paraffinic diesel fuel from bio-hydrocarbons — the standard implementing EN 12662-1 (Journal of Laws 2025, item 1341, Part II point 11, Part III point 10)
• Methyl ester used as a self-contained fuel (neat FAME) — outside the scope of Part 1; it is tested according to EN 12662-2 (Journal of Laws 2025, item 1341, Part I point 16)

Key parameters

Standard

Standard number

PN-EN 12662-1:2024-11

Title (PL)

Ciekłe przetwory naftowe — Oznaczanie całkowitej zawartości zanieczyszczeń — Część 1: Średnie destylaty i oleje napędowe

Title (EN)

Liquid petroleum products — Determination of total contamination — Part 1: Middle distillates and diesel fuels

Step-by-step procedure

1. Cleaning containers and apparatus

   Every surface that comes into contact with the sample or heptane, or can transfer extraneous matter to the filter, is washed in turn with warm water containing detergent, warm water, water, propan-2-ol and heptane; the openings of the container and funnel are covered with film rinsed with heptane. The test is performed in a clean environment (EN 12662:2014, clause 7).

2. Sampling

   According to EN ISO 3170, EN ISO 3171 or EN 14275, directly into a prepared glass container (brown or shielded from light), filled to 80–85 % of its capacity; dynamic sampling from a pipeline loop after flushing the line with fuel is preferred (clause 8).

3. Sample preparation

   The container is washed on the outside if particles may adhere to it. With its closure loosened, it is heated in a water bath or oven at 40 °C for 30–60 min so that separated components dissolve again, then the closure is tightened, the container is cooled to room temperature and washed on the outside with propan-2-ol (9.1–9.2.2). Further homogenization (9.2.3 onwards) — outside the available text.

4. Preparation of the apparatus and filter

   Clause 10 (filtration apparatus — 10.1, filter — 10.2) is outside the available text; the filter is weighed before filtration (clause 4).

5. Filtration, washing, drying and weighing

   A weighed test portion is filtered under vacuum through the pre-weighed filter; viscous products after dilution with the solvent. The filter with the residue is washed, dried and weighed (clause 4); details — clause 11, outside the available text.

6. Calculation and result

   The contamination is calculated from the difference in filter mass relative to the sample mass and expressed in mg/kg (clause 4). Formula, rounding and precision (clauses 12–14) — outside the available text.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard does not address all hazards associated with its use — safety measures are established by the user (warning in clause 1)
• The filter drying oven must be explosion-proof (EN 12662:2014, 6.6), and the filtration apparatus has an earthing wire (Figure 1)
• Heptane, xylene and propan-2-ol are flammable — precautions according to the safety data sheets

Frequently asked questions