Test methods pursuant to EC A.21. (Regulation (EC) No 440/2008 Annex “Part A: Methods for the determination of physicochemical properties, A.21. Oxidizing properties (liquids)”

Oxidizing liquids are liquid substances or mixtures which, although not necessarily combustible themselves, may generally cause or support a fire in other materials by releasing oxygen.

This test is used to determine the oxidizing properties of liquid substances and mixtures as a criterion for evaluation from a safety perspective or for classification in hazard classes and packing groups within the framework of relevant regulations, in particular pursuant to Regulation (EC) No 440/2008 Annex “Part A: Methods for the determination of physicochemical properties, A.21. Oxidizing properties (liquids)”.

The test and reference substance are mixed at 1:1 weight ratio with a defined combustible substance (cellulose). The mixture is filled into a pressure vessel, in which a heating coil is located at the lower end. The pressure vessel is then closed with a bursting disc at the upper end. The heating coil is then activated and the time pressure profile is measured. The time taken for the pressure to rise from 690 kPa to 2 070 kPa above atmospheric is noted.

The mean pressure rise times are calculated for both the test substance and the reference substance.

The test results are assessed on the basis of:

• whether the mixture of test substance and cellulose spontaneously ignites; and
• the comparison of the mean time taken for the pressure to rise from 690 kPa to 2 070 kPa with that of the reference substances.

A test substance is to be considered oxidizing if:

• a 1:1 mixture, by mass, of the substance and cellulose spontaneously ignites; or
• a 1:1 mixture, by mass, of the substance and cellulose exhibits a mean pressure rise time less than or equal to the mean pressure rise time of a 1:1 mixture, by mass, of 65% (w/w) aqueous nitric acid and cellulose.

Figure: Test method for the test pursuant to EC A.21.