🔥 Flash Point by the Pensky-Martens Method

Petrochemistry PN-EN ISO 2719

Overview

STATUS (as of 28.10.2026). PN-EN ISO 2719:2026-06 — English version, published 11.06.2026, implements EN ISO 2719:2025 and ISO 2719:2025 [IDT]; it replaced PN-EN ISO 2719:2016-08 and its amendment A1:2021-06 (Polish and English versions), which were withdrawn on 11.06.2026. There is no Polish version of the current edition yet.

SCOPE (clause 1). The standard gives three procedures — A, B and C — for determining the flash point in the Pensky-Martens closed cup for combustible liquids, liquids with suspended solids, liquids that tend to form a surface film under the test conditions, biodiesel and other liquids, in the range from 40 °C to 370 °C. Procedure A applies to distillate fuels (diesel, biodiesel blends, heating oil, turbine fuels), new and in-use lubricating oils, paints and varnishes and other homogeneous liquids not covered by procedures B and C. Procedure B — residual fuel oils, cutback residua, used lubricating oils, mixtures of liquids with solids, and liquids that form a surface film or are of such viscosity that they are not uniformly heated under the stirring and heating conditions of procedure A. Procedure C — fatty acid methyl esters (FAME) conforming to specifications such as EN 14214 or ASTM D6751. The standard does not apply to water-borne paints and varnishes (ISO 3679 applies to them); liquids containing traces of highly volatile components are tested according to ISO 1523 or ISO 3679. Kerosine with a flash point above 40 °C can technically be tested by this method, but the accepted practice is to test it according to ISO 13736, and lubricating oils are usually tested according to ISO 2592.

EDITION (foreword). The fifth edition ISO 2719:2025 replaced the fourth edition of 2016 together with Amendment 1:2021. Changes include definition 3.1, the clauses on the apparatus, its set-up and verification, the correction of the result (11.2) and the test report; Annex A — verification of the apparatus with reference materials — has become normative, and a new normative Annex D specifies requirements for hot-wire igniters and flash detectors.

WHAT THE RESULT MEASURES (introduction). The flash point is not a physico-chemical constant of the material: it depends on the design and condition of the apparatus and on the course of the test, so it is defined only by a standardised method, and there is no generally valid correlation between results of different methods or of apparatus other than the one specified. Flash point values are used in transport, storage and safety regulations to classify materials as "flammable" and "combustible" — the exact class limits are given by each regulation. The result can also indicate the presence of highly volatile components in a relatively non-volatile material.

UNSTABLE MATERIALS (introduction). Potentially unstable, decomposable or explosive materials should not be tested until it has been established that heating the quantity specified in the method in contact with the metal parts of the apparatus over the required temperature range does not cause decomposition, explosion or other adverse effects.

HOW THE TEST PROCEEDS — ACCORDING TO THE 1988 EDITION. In the 1988 edition the sample in the cup closed with the lid is heated at 5–6 °C/min while stirring at 90–120 rpm; the test flame is dipped into the vapour space above the liquid (lowered in 0.5 s, left for 1 s) without stirring at that moment — every 1 °C when the expected flash point does not exceed 110 °C and every 2 °C above that, starting 17–28 °C below the expected value. The flash point is the reading at which the second or a later (up to the twentieth) application causes a distinct flash inside the cup; a bluish halo around the test flame is not a flash. For highly viscous liquids: stirring at 250 ± 10 rpm and heating at 1–1.5 °C/min. The result is corrected to a pressure of 101.3 kPa: corrected result = reading + 0.25 · (101.3 − p), p in kPa. The current edition retains the division into procedures, the pressure correction (clause 11) and the precision data (clause 13), but the values have to be checked in its clause 10.

WHAT WE DO NOT GIVE HERE. The values of the current edition for procedures A, B and C (heating and stirring rates, intervals of applying the ignition source), the requirements for the apparatus, the temperature sensor and the igniters (Annexes B–D), the method of verifying the apparatus with reference materials (Annex A) and the precision data (clause 13) — we only know the titles of these clauses.

Method principle

The sample in the Pensky-Martens cup, closed with a lid carrying the ignition device, is heated with continuous stirring, and at specified temperature intervals the ignition source is directed into the vapour space above the liquid. The flash point is the lowest temperature, corrected to a pressure of 101.3 kPa, at which the ignition source causes the vapour above the sample to ignite under the test conditions.

The standard has three procedures: A — for homogeneous liquids (distillate fuels, lubricating oils, paints and varnishes), B — for viscous liquids, liquids with suspended solids or liquids forming a surface film that are not heated uniformly under the conditions of procedure A, C — for FAME. The result depends on the apparatus and the course of the test, so it is valid only with reference to this method.

Applications

• Distillate fuels — diesel, biodiesel blends, heating oil, turbine fuels (procedure A)
• New and in-use lubricating oils, paints and varnishes (except water-borne ones) and other homogeneous liquids (procedure A)
• Residual fuel oils, used lubricating oils, liquids with suspended solids and liquids forming a surface film (procedure B)
• Fatty acid methyl esters (FAME) conforming to specifications such as EN 14214 (procedure C)
• Classification of flammable and combustible materials in transport, storage and safety regulations — class limits according to the regulation concerned

Key parameters

Standard

Standard number

PN-EN ISO 2719:2026-06

Title (PL)

Oznaczanie temperatury zapłonu — Metoda zamkniętego tygla Pensky’ego-Martensa

Title (EN)

Determination of flash point — Pensky-Martens closed cup method

Step-by-step procedure

1. Assessment of the material

   Do not test potentially unstable, decomposable or explosive materials until it has been established that heating them in the apparatus will not cause decomposition or explosion (introduction). Choose procedure A, B or C according to the type of sample (clause 1).

2. Preparation of the apparatus

   Set-up of the apparatus, cleaning of the cup, assembly and verification with reference materials — according to clause 7 and Annex A of the standard.

3. Sampling and sample preparation

   According to clauses 8–9 of the standard — separately for petroleum products (subsampling, samples containing undissolved water, liquid, highly viscous, semi-solid and solid samples) and for paints and varnishes.

4. Determination

   Fill the cup to the mark, close it with the lid, heat with stirring and direct the ignition source into the vapour space above the liquid — according to procedure A, B or C (clause 10). A bluish halo around the test flame is not regarded as a flash.

5. Pressure correction and result

   The observed flash point is corrected to a pressure of 101.3 kPa (clause 11); result and test report — according to clauses 12 and 14, precision — clause 13.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Do not test potentially unstable, decomposable or explosive materials without first establishing that heating them in the apparatus is safe (introduction of the standard)
• During the test the vapour above the cup ignites — place the apparatus in the location specified in 7.2 of the standard, away from combustible materials, and do not lean over the cup while applying the ignition source
• The cup and the sample reach high temperatures (method range up to 370 °C) — protect your hands when removing them

Frequently asked questions