This part of ISO 12989 allows the determination by thermogravimetric analysis (TGA) of air reactivities and dusting of shaped carbon electrodes used in the aluminium-reduction industry. Many types of apparatus are available, with various thermal conditions, sample-size capabilities, materials of construction and procedures for determining the mass loss and subsequent rate of reaction. This test method standardizes the variables of sample dimensions, reaction times and temperatures, and provides a mathematical method to normalize the gas velocity over the exposed surfaces, such that results obtained on different types of apparatus are correlatable