This document establishes a method for the estimation of the storage stability of thermosetting coating powders. It provides the procedures for determining the changes both in the physical state of a thermosetting coating powder and in its chemical reactivity, together with its capacity to form a satisfactory final coating. A correlation between changes in different properties is not to be expected. Similarly, there may be no correlation between the results obtained under different storage conditions. The results of the procedures in this document give an indication of the ability of the coating powder to withstand the effects of storage prior to application.