The indentation hardness of flexible cellular materials is a measure of their load-bearing properties. ISO 2439:2008 specifies four methods (A to D) for the determination of indentation hardness and one method (E) for determination of compressive deflection coefficient and hysteresis loss rate of flexible cellular materials. Annex A provides a summary of test parameters and typical force-indentation graphs obtained with these methods.
These five methods are applicable only to latex foam, urethane foam and PVC foam of the open-cell type. The methods specified can be used for testing finished articles and for the characterization of bulk material.