1.1 This part of ISO 20557 establishes a system of designation for PPE thermoplastic materials, which may be used as the basis for specifications. 1.2 The types of PPE plastic are differentiated from each other by a classification system based on appropriate levels of the designatory properties a) temperature of deflection under load b) melt volume-flow rate c) Charpy notched impact strength d) flammability and on information about basic polymer parameters, intended application and/or method of processing, important properties, additives, colorants, fillers and reinforcing materials. 1.3 This part of ISO 20557 is applicable to all PPE materials, including those modified with polystyrene or polyamide or other materials. 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 One should not assume that materials having the same designation give the same performance.This part of ISO 20558 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 ISO 20557 2, if suitable. 1.5 In order to specify a thermoplastic material for a particular application or to ensure reproducible processing, the requirements are to be given in data block 5 (see 3.1).