Is applicable to natural and processed iron ores containing from 1 % to 25 % acid-soluble iron(II) and only traces of metallic iron. Is limited for use in conjunction with the reducibility test methods. Is not applicable to ores containing more than 0,3 % (m/m) sulfur (as sulfide) and/or 5 % free carbon. Specifies principle, reagents, apparatus, sampling and samples, procedure, expression of results and test report. Includes three annexes.