This International Standard specifies a general procedure for the production, by injection-moulding, of tubular test pieces for the determination of the resistance to internal pressure. It also specifies the design of the mould to be used. By using the same material as for injection-moulded piping components, such as fittings, these test pieces make it possible to determine the time-related behaviour of the fitting material under hydrostatic pressure and under the very same conditions as specified for extruded pipes. It is possible to test the resistance to internal pressure of the injection-moulded tubular test pieces in accordance with ISO 1167, to extrapolate the results in accordance with a method such as that specified in ISO 9080 in order to determine the MRS, and to classify the material in accordance with ISO 12162. The tubular test pieces also make it possible to verify individual points on previously established stress/time regression curves as a minimum material test requirement. The basis established by this International Standard allows test pieces to be prepared reproducibly. Nevertheless, the method given is a general one, and the injection-moulding parameters have to be specified for every material used. NOTE If the compound used for the injection-moulding of piping components can also be extruded, then its time-related behaviour may be investigated using either injection-moulded or extruded tubular test pieces.