This part of ISO 21305 establishes a system of designation for polycarbonate (PC) moulding and extrusion materials, which may be used as the basis for specifications.The types of polycarbonate plastic are differentiated from each other by a classification system based on appropriate levels of the designatory properties a) melt volume-flow rate; b) Charpy notched impact strength; and on information about the intended application and/or method of processing, important properties, additives, colorants, fillers and reinforcing materials. This part of ISO 21305 is applicable to all polycarbonate homopolymers and copolymers s. It applies to unmodified materials ready for normal use and materials modified, for example, by colorants, additives, fillers, reinforcing materials, and polymer modifiers. One should not assume that materials having the same designation give the same performance. This part of ISO 21305 does not provide engineering data, performance data or data on processing conditions which may be required to specify a material. If such additional properties are required, they shall be determined in accordance with the test methods specified in Part 2 of this International Standard, if suitable. In order to designate a thermoplastic material to meet particular specifications, the requirements are to be given in data block 5 (see 4.6).