ISO 12989-2:2004 covers the thermogravimetric analysis (TGA) of air reactivities and dusting of shaped carbon electrodes used in the aluminium-production industry. Many types of apparatus are available, with various thermal conditions, sample-size capability, materials of construction and procedures for determining the mass loss and subsequent rate of reaction. This test method sets standard 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.