Specifies a method for the determination of the resistance of moulded test specimens of propylene and propylene-copolymers to acclerated ageing at specified temperatures in the range from 100 to 150oC in a forced draught oven. Rotating specimen holders are recommended.- The time to failure is determined by visual examination and taken as the number of days after which a specimen shows localized crazing, crumbling and/or discoloration. The test may be conducted at several temperatures and the data interpreted by the use of the Arrhenius relation.