⛽ Fuel lubricity HFRR
In short
Assessment of the lubricating properties of fuels for compression-ignition engines in the high-frequency reciprocating rig (HFRR): a loaded steel ball oscillates against a stationary steel plate immersed in the sample, and lubricity is measured by the wear scar diameter (WSD) on the ball. The test is performed according to PN-EN ISO 12156-1:2024-02; Range: WSD 350–700 µm (clause 1). The procedure comprises 5 steps; it is used for: Diesel fuel — WSD at 60 °C at most 460 µm (Journal of Laws 2024, item 1018, Annex 3 item 16); method according to Journal of Laws 2024, item 1058, Annex Part II point 13, Petroleum-based middle distillate fuels, paraffinic diesel fuels and biodiesel blends — with or without lubricity-enhancing additives (clause 1), Fuels with a wear scar diameter from 350 µm to 700 µm (clause 1).
At a glance
- Standard: PN-EN ISO 12156-1:2024-02
- Category: Petrochemistry
- Procedure steps: 5
- Range: WSD 350–700 µm (clause 1)
- Fluid temperature: (60 ± 2) °C (Table 1)
- Load: mass (200 ± 1) g including fixing elements (Table 1)
Overview
STATUS (as of 02.11.2026). PN-EN ISO 12156-1:2024-02 — Polish version, published 09.05.2025, implements EN ISO 12156-1:2023 and ISO 12156-1:2023 [IDT]; it replaced PN-EN ISO 12156-1:2018-12 (Polish and English versions). The PKN catalogue card has no withdrawal note — the standard is current. ISO 12156-1:2023 is the fifth edition, published in September 2023; changes compared with the 2018 edition (foreword): the scope was broadened, a new precision statement using the linear transformation required by ISO 4259-1 was added, and “Method B” — visual observation — was removed.
SCOPE (clause 1). Test method using the high-frequency reciprocating rig (HFRR) with a digital camera, for assessing the lubricating properties of petroleum-based middle distillate fuels, paraffinic diesel fuels and biodiesel blends, with or without lubricity-enhancing additives, for wear scar diameters (WSD) from 350 µm to 700 µm. It applies to fuels used in compression-ignition engines. The standard notes that it is not known whether the method can predict the performance of all fuel/additive combinations.
WHY IT IS TESTED (introduction). All diesel fuel injection equipment relies to some extent on the fuel as a lubricant; shortened life of injection pumps and injectors due to wear from excessive friction has sometimes been ascribed to a lack of fuel lubricity. A relationship between test results and component wear has been demonstrated for some fuel/hardware combinations in which boundary lubrication plays a role; according to the standard, the results correlate with many such combinations and provide an adequate prediction of the lubricating quality of the fuel, and the correlation for biodiesel blends has been confirmed by 15 years of field experience. The corresponding American standard ASTM D6079 (5.3, 5.5) adds that the wear scar is sensitive to contamination of the fluids and test materials, the fuel temperature and the ambient relative humidity, and that the correlation of results with the field performance of injection systems has not yet been determined.
HOW THE TEST PROCEEDS (clauses 4–7). The sample is placed in a reservoir kept at the test temperature. A steel ball held in a vertically mounted chuck is pressed with an applied load against a horizontally mounted, stationary steel plate and oscillates at a fixed frequency and stroke length, with the contact fully immersed in the fluid; the wear scar on the ball is the measure of lubricity (clause 4). Conditions (Table 1): fluid volume (2 ± 0.2) ml, stroke (1 ± 0.02) mm, frequency (50 ± 1) Hz, fluid temperature (60 ± 2) °C, test mass (200 ± 1) g including fixing elements, duration (75 ± 0.1) min, reservoir surface area (600 ± 100) mm²; the air temperature and humidity measured 0.1–0.25 m from the reservoir must lie within the acceptable area of Figure 2. The plate is made of 100Cr6 steel (ISO 683-17), with a Vickers hardness (HV 30) of 190 to 210 and a surface finish of Ra < 0.02 µm; the ball is 6.00 mm in diameter, grade G28 (ISO 3290-1), made of 100Cr6 steel, with a hardness of HRC 58 to 66 (6.2–6.3). The scar is measured with a microscope with a digital camera at 100× magnification and a resolution of at least 2,048 × 1,536 pixels, with cursors positioned at the scar boundaries to within 1 µm (6.4). The performance of the rig is verified with two reference fluids: A — good lubricity and B — poor lubricity, marked with the WSD value and its expanded uncertainty (5.3). Samples are taken according to ISO 3170 or ISO 3171 into fully epoxy-lined metal containers or amber borosilicate glass containers with an aluminium foil-lined insert cap, rinsed at least three times with the product before use (ASTM D4306:2020, 6.7); new containers are preferred because lubricity measurement is sensitive to trace contaminants (clause 7).
LEGAL REQUIREMENTS. Diesel fuel: lubricity — wear scar diameter (WSD) at 60 °C at most 460 µm, 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 16). The regulation on test methods for the quality of liquid fuels (Journal of Laws 2024, item 1058, Annex Part II point 13) describes the method — HFRR rig, ball pressed against a stationary plate, both fully immersed in the sample, lubricity measured by the WSD formed under closely controlled conditions — and refers to the standard implementing EN ISO 12156-1.
WHAT WE DO NOT GIVE HERE. The publicly available text of ISO 12156-1:2023 covers clauses 1–7 (up to sampling). We do not give the preparation and calibration of the apparatus (clause 8), the test procedure (clause 9), the method of measuring the scar and expressing the result (clauses 10–11, informative Annex A) or the repeatability and reproducibility values (clause 12).
Method principle
A sample of the fluid under test is placed in a reservoir kept at the test temperature. A steel ball held in a vertically mounted chuck is pressed with an applied load against a horizontally mounted, stationary steel plate and oscillates at a fixed frequency and stroke length, while the contact with the plate is fully immersed in the fluid.
The metallurgy of the ball and plate, the fluid temperature, load, frequency, stroke length and the air temperature and humidity during the test are specified. The wear scar generated on the ball is the measure of the lubricity of the fluid (clause 4); the result is the wear scar diameter (WSD) — the mean diameter of the scar on the ball (definition 3.3).
Applications
- Diesel fuel — WSD at 60 °C at most 460 µm (Journal of Laws 2024, item 1018, Annex 3 item 16); method according to Journal of Laws 2024, item 1058, Annex Part II point 13
- Petroleum-based middle distillate fuels, paraffinic diesel fuels and biodiesel blends — with or without lubricity-enhancing additives (clause 1)
- Fuels with a wear scar diameter from 350 µm to 700 µm (clause 1)
- Comparison of the effectiveness of fuels in preventing wear under the test conditions; correlation with the field performance of injection systems has not been determined (ASTM D6079, 5.5)
Key parameters
| Parameter | Value |
|---|---|
| Range | WSD 350–700 µm (clause 1) |
| Fluid temperature | (60 ± 2) °C (Table 1) |
| Load | mass (200 ± 1) g including fixing elements (Table 1) |
| Ball motion | stroke (1 ± 0.02) mm, frequency (50 ± 1) Hz, duration (75 ± 0.1) min (Table 1) |
| Sample | volume (2 ± 0.2) ml; reservoir surface area (600 ± 100) mm² (Table 1) |
| Requirement for diesel fuel | WSD at 60 °C at most 460 µm (Journal of Laws 2024, item 1018, Annex 3 item 16) |
Standard
- Standard number
- PN-EN ISO 12156-1:2024-02
- Title (PL)
- Oleje napędowe — Ocena smarności z zastosowaniem aparatu o ruchu posuwisto-zwrotnym wysokiej częstotliwości (HFRR) — Część 1: Metoda badania
- Title (EN)
- Diesel fuel — Assessment of lubricity using the high-frequency reciprocating rig (HFRR) — Part 1: Test method
Step-by-step procedure
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Sampling
According to ISO 3170 or ISO 3171, into a fully epoxy-lined metal container or an amber borosilicate glass container with an aluminium foil-lined insert cap, rinsed at least three times with the product (ASTM D4306:2020, 6.7); new containers are preferred (clause 7).
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Laboratory conditions
The air temperature and humidity are measured 0.1–0.25 m from the reservoir; during the test they must lie within the acceptable area of Figure 2 (Table 1).
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Preparation and calibration of the rig
Preparation of plates, balls and hardware, calibration of temperature, frequency, stroke length and duration, and verification of rig performance (clause 8) — outside the available text; reference fluids A and B are used for verification (5.3).
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Test
(2 ± 0.2) ml of sample is placed in the reservoir with the plate; the ball loaded with a mass of (200 ± 1) g oscillates with a stroke of (1 ± 0.02) mm at a frequency of (50 ± 1) Hz for (75 ± 0.1) min at a fluid temperature of (60 ± 2) °C (Table 1); sequence of operations — clause 9, outside the available text.
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Scar measurement and result
The scar on the ball is measured with a microscope with a digital camera (6.4); the result is the wear scar diameter WSD in µm (definition 3.3). The method of measurement and of expressing the result — clauses 10–11 and informative Annex A, outside the available text.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| HFRR rig | steel ball pressed against a stationary plate and oscillating while immersed under the conditions of Table 1; reservoir holding the plate rigidly, heated by a closely attached electric heater pad; control unit with data storage and electronic calibration of the stroke length (6.1) | — |
| Test plates | 100Cr6 steel (ISO 683-17) machined from annealed rod, Vickers hardness (HV 30) 190 to 210 (ISO 6507-1), lapped and polished to Ra < 0.02 µm (ISO 21920-3) (6.2) | — |
| Test balls | 6.00 mm in diameter, grade G28 (ISO 3290-1), 100Cr6 steel, hardness HRC 58 to 66 (ISO 6508-1) (6.3) | — |
| Microscope with digital camera | 100× magnification, resolution at least 2,048 × 1,536 pixels, cursors positioned at the scar boundaries to within 1 µm (6.4) | — |
| Desiccator and ultrasonic bath | desiccator with a drying agent for storing plates, balls and hardware; cleaning bath with a seamless stainless-steel tank, power at least 40 W (6.5–6.6) | — |
| Timer | mechanical or electronic, measuring (75 ± 0.1) min (6.7) | — |
| Laboratory air monitoring | air temperature and relative humidity measured 0.1–0.25 m from the reservoir, within the acceptable area of Figure 2 (Table 1, footnote a) | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Reference fluids A and B | — | A — good (high) lubricity, B — poor (low) lubricity; marked with the WSD value and its expanded uncertainty in µm; for verifying the rig; stored in the dark, in borosilicate glass with an aluminium foil-lined insert cap or in an epoxy-lined metal container (5.3) |
| Heptane | 142-82-5 | reagent grade (5.5) |
| Isooctane (2,2,4-trimethylpentane) | 540-84-1 | reagent grade (5.6) |
| Propan-2-ol | 67-63-0 | reagent grade (5.7) |
| Acetone | 67-64-1 | analytical reagent grade (5.2) |
| Toluene | 108-88-3 | according to ISO 5272 (5.9) |
| Compressed air | — | if needed for drying the components: 140–210 kPa, less than 0.1 ml/m³ hydrocarbons and less than 50 ml/m³ water (5.1) |
| Gloves and wipers | — | gloves appropriate for the reagents used; disposable, lint-free, hydrocarbon-free wipers (5.4, 5.8) |
Health and safety (OHS)
- The standard does not address all hazards associated with its use — safety measures are established by the user (warning in the standard)
- Acetone, heptane, isooctane and propan-2-ol are extremely flammable, and their vapours can cause a flash fire (warnings in 5.2 and 5.5–5.7)
- Toluene is extremely flammable, can be fatal if swallowed and enters the airways, can cause drowsiness or dizziness, is suspected of damaging the unborn child and can cause damage to organs through prolonged or repeated exposure (warning in 5.9)
- Compressed air is used with extreme caution in the presence of combustible material (warning in 5.1); the reference fluids are flammable (warning in 5.3)
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN ISO 12156-1:2024-02 — “Diesel fuel — Assessment of lubricity using the high-frequency reciprocating rig (HFRR) — Part 1: Test method”.
How does this method work?
A sample of the fluid under test is placed in a reservoir kept at the test temperature. A steel ball held in a vertically mounted chuck is pressed with an applied load against a horizontally mounted, stationary steel plate and oscillates at a fixed frequency and stroke length, while the contact with the plate is fully immersed in the fluid.
What is the measuring range and accuracy?
Range: WSD 350–700 µm (clause 1); Fluid temperature: (60 ± 2) °C (Table 1); Load: mass (200 ± 1) g including fixing elements (Table 1); Ball motion: stroke (1 ± 0.02) mm, frequency (50 ± 1) Hz, duration (75 ± 0.1) min (Table 1).
How long does the test take?
The procedure comprises 5 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
HFRR rig, Test plates, Test balls, Microscope with digital camera, Desiccator and ultrasonic bath, Timer, Laboratory air monitoring.
Where is this test used?
Diesel fuel — WSD at 60 °C at most 460 µm (Journal of Laws 2024, item 1018, Annex 3 item 16); method according to Journal of Laws 2024, item 1058, Annex Part II point 13; Petroleum-based middle distillate fuels, paraffinic diesel fuels and biodiesel blends — with or without lubricity-enhancing additives (clause 1); Fuels with a wear scar diameter from 350 µm to 700 µm (clause 1); Comparison of the effectiveness of fuels in preventing wear under the test conditions; correlation with the field performance of injection systems has not been determined (ASTM D6079, 5.5).
What safety precautions apply?
The standard does not address all hazards associated with its use — safety measures are established by the user (warning in the standard); Acetone, heptane, isooctane and propan-2-ol are extremely flammable, and their vapours can cause a flash fire (warnings in 5.2 and 5.5–5.7); Toluene is extremely flammable, can be fatal if swallowed and enters the airways, can cause drowsiness or dizziness, is suspected of damaging the unborn child and can cause damage to organs through prolonged or repeated exposure (warning in 5.9); Compressed air is used with extreme caution in the presence of combustible material (warning in 5.1); the reference fluids are flammable (warning in 5.3).
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 12156-1.