ISO 23228:2011 specifies a method for the determination of the time-to-failure of thermoplastics resins and compounds for piping and fitting applications by the use of a plane strain grooved tensile specimen in a stress-rupture test.The grooved tensile specimen produces a biaxial state of stress on uni-axial loading, which is taken to be indicative of the stress conditions found in pressurized solid-wall plastics pipes. The ratio of the stress in the axial direction to the transverse direction approximates that for a pressurized end-capped solid-wall pipe specimen.It is intended that the data generated on these specimens be utilized to determine the stress-rupture (time-to-failure) resistance of moulding materials for pipes and fittings as well as experimental piping resins.This method is also applicable to stress-rupture evaluations of pipes which are difficult to test, e.g. larger diameter pipes, including their batch release tests.ISO 23228:2011 is not intended to replace the stress-rupture test of ISO 1167, which uses internally pressurized end-capped pipes.