This International Standard specifies a method for the determination of loss of mass on heating of aluminium oxide at 300 °C and further loss of mass on ignition at 1 000 °C. By industry convention, these mass losses are often referred to as “moisture (MOI)” and “loss on ignition (LOI)” respectively. This method is suitable for calcined alumina in the range 0,2 % to 5 % loss of mass at 300 °C and 0,1 % to 2 % loss of mass at 1 000 °C. This method provides for samples to be treated on an “as-received” basis for determination of actual MOI and LOI in alumina samples. To improve precision of analysis in cases where “as-received” results are not required, samples can be “air-equilibrated” prior to analysis. “Air-equilibration” can greatly affect MOI results and significantly alter LOI results. The “air-equilibration” procedure and its effects are discussed in Annex A. Instrumental methods are also discussed.