EU A.17: Oxidising properties

Knowledge of the oxidising properties of a substance is an important safety consideration. If oxidising substances are handled or stored incorrectly then there can be serious consequences, such as a fire or explosion.

The purpose of the study is to determine the oxidizing properties of the solid test item.

It is useful to have preliminary information on any potentially explosive properties of the substance before performing this test.

(This test is not applicable to liquids, gases, explosive or highly flammable substances, or organic peroxides).

Study Design

Course of the test

A preliminary test is carried out in the interests of safety. No further testing is required when the preliminary test clearly indicates that the test substance has oxidizing properties. When this is not the case, the substance should then be subject to the full test.

In the full test, the substance to be tested and a defined combustible substance will be mixed in various ratios. Each mixture is then formed into a pile and the pile is ignited at one end. The maximum burning rate determined is compared with the maximum burning rate of the reference mixture. If the maximum burning rate will found to be significantly greater than that from the reference mixture, the test can be stopped; otherwise the test should be repeated six times for each of the three mixtures giving the fastest reaction rate.

The test item will be reduced to a particle size < 125 µm if applicable. Before preparing the mixture the grinded test item will be dried at 105 °C until constant weight will be obtained. If the decomposition temperature of the test item is below 105 °C the test item will be dried at a suitable lower temperature.


The burning rate will be expressed in millimetres per second. The maximum burning rate (not the mean value) will be considered to be the characteristic oxidizing property of the test item. The highest value of a burning rate for each mixture will be relevant for evaluation. A graph of the highest burning rate for each mixture versus the oxidizer concentration will be plotted.

A substance is considered as an oxidizing substance when in the preliminary test a vigorous reaction is observed or when in the main test the maximum burning rate of the mixtures tested is higher than or equal to the maximum burning rate of the reference mixture.

Guidelines and literature

  • Commission Regulation (EC) No.440/2008 laying down test methods pursuant to Regulation (EC) No.1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) (originally published as Council Regulation (EC) No.440/2008, corrigendum according to Official Journal of the European Union (EN) dated June 3, 2008, L 143/55), Annex, Part A, A.17: “Oxidizing Properties (solids)“, Official Journal of the European Union, L 142, Volume 51, 31 May 2008