This International Standard specifies a method for the determination of the mechanical, electrical, thermal and other properties of thermosetting moulding materials when tested under defined conditions at elevated temperatures. The method is used for the determination of the relative Performance temperature (RPT) of thermosetting moulding materials. This RPT is necessary in describing the short-term Performance of these materials at elevated temperatures. Coupled with the long-term property evaluations of polymeric materials, the RPT provides designers and engineers with a more complete picture of the expected Performance of materials in use at elevated temperatures.