ISO 1268-4:2005 describes the preparation of test plates from layers of preimpregnated unidirectional fibre or fabric (prepregs) under pressure and temperature in various types of equipment (for example, autoclave, bladder press, hydraulic press or vacuum bag equipment). It applies to all reinforcements and resins.

This method is applicable to reinforcements preimpregnated either with a partially cured thermosetting resin or with a thermoplastic resin. The test plate is formed by stacking layers of the preimpregnated material in the required sequence and orientation, followed by compaction and final consolidation under pressure/vacuum at a temperature above ambient. The prepared test plates are subsequently machined into the required test specimens.

Standard plates prepared in this manner may be used either for evaluating the components, i.e. the reinforcement, finish, resin, etc., or for verifying the overall quality of the finished product.