ISO 1209-1:2007 specifies a simple method for assessing the behaviour of a bar of rigid cellular plastic under the action of three-point bending.

It may be used to determine either the load for a specified deformation or the load at break.

The version of the method specified uses small test specimens and does not produce pure bending. Hence it does not permit the calculation of the flexural strength or the apparent flexural modulus (modulus of elasticity). The user is referred to ISO 1209-2 for the determination of these parameters.

The method is not applicable to cellular plastics in which significant crushing is observed. Numerical values should be compared only when determined on materials of similar physical properties and dimensions.

The method is limited to materials of 20 mm thickness or greater.