BS EN 15751:2025

This document specifies a test method for the determination of the oxidation stability of fuels for diesel engines at 110 °C, by means of measuring the induction period of the fuel up to 48 h. The method is applicable to fatty acid methyl esters (FAME) intended for the use as pure biofuel or as a blending component for diesel fuels, and to blends of FAME with diesel fuel containing 2 % (V/V) of FAME at minimum. The precision of the test method has been developed for conventional diesel. This test method is applicable for paraffinic diesel fuels as specified in EN 15940, however, a separate precision statement for paraffinic diesel is not available. NOTE 1 EN 14112 [1] describes a similar test method for the determination of the oxidation stability of pure fatty acid methyl esters (see the Introduction to this document). Additionally, EN 16568 [4] describes a similar test method for the determination of the oxidation stability of fuels for diesel engines at 120 °C, by means of measuring the induction period of the fuel up to 20 h. EN 16568 is applicable to blends of FAME with diesel fuel containing 2 % (V/V) of FAME at minimum. Other alternative test methods for the determination of the oxidation stability of distillate fuels are described in CEN/TR 17225 [5]. NOTE 2 For induction periods higher than 48 h the precision is not covered by the precision statement of this method. The limit values of the relevant fuel standards are well within the scope of this test method. NOTE 3 The presence of cetane improver can reduce the oxidation stability determined by this test method. Limited studies with EHN (2-ethyl hexyl nitrate) indicated, however, that the stability is reduced to an extent which is within the reproducibility of the test method. NOTE 4 For the purposes of this document, the term “% (V/V)” is used to represent the volume fraction (φ) of a material.