1.1 This part of ISO 11542 establishes a system of designation for PE UHMW thermoplastic materials, which may be used as the basis for specifications. For the purposes of this part of ISO 11542, PE UHMW materials are polyethylene materials having a melt mass-flow rate (MFR), measured at 190 °C and 21,6 kg load, of less than 0,1 g/10 min. 1.2 The types of PE UHMW are differentiated from each other by a classification system based on appropriate levels of the designatory properties a) viscosity number b) elongational stress c) Charpy notched impact strength and on information about intended application and/or method of processing, important properties, additives, colorants, fillers and reinforcing materials. 1.3 This part of ISO 11542 is applicable to all PE UHMW homopolymers and to ultra-high-molecular-weight copolymers of ethylene having a content of other 1 olefinic monomers of less than 50 % by mass and a content of non-olefinic monomers with functional groups up to a maximum of 3 % by mass. It applies to materials ready for normal use in the form of powder, granules or pellets and to materials unmodified or modified by colorants, additives, fillers, etc. 1.4 It is not intended to imply that materials having the same designation give necessarily the same performance. This part of ISO 11542 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, they shall be determined in accordance with the test methods specified in part 2 of this International Standard, if suitable. 1.5 In order to specify a thermoplastic material for a particular application or to ensure reproducible processing, additional requirements may be given in data block 5 (see 3.1).