This European Standard establishes a data block system for the designation of glass mat reinforced thermoplastic composite sheet (GMT). The types of thermoplastic composite sheets are differentiated from each other by a classification system based on information about basic polymer parameters, fillers/reinforcement content and type, intended method of processing and/or manufacturing, specific characteristics and designatory properties. This European Standard is applicable to glass fibre mat reinforced polypropylene sheet materials only. It applies to materials ready for commercial use in the form of flat sheet or coil. This European Standard does not apply to: -- thermoplastic sheet moulding materials where the polymer is other than polypropylene or polypropylene alloy or a blend; -- the reinforcement is other than glass fibre. It is not intended to imply that materials having the same designation give necessarily the same performance. This European Standard does not provide engineering data, performance data or data on processing conditions which may be required to specify a material for a particular application and/or method of processing. If such additional properties are required, when ever possible, they shall be determined in accordance with the test methods specified in Part 2 of this European Standard. Whenever technical properties required in the Part 3 of this standard need to be indicated, this data block system is also the basis for it. To ensure that the meanings of codes remain unambiguous and to avoid conflicts within the system, codes and abbreviations have been co-ordinated within the relevant ISO technical sub-committees.