ISO 16589 describes seals utilizing sealing elements manufactured from suitably formulated compounds, based on thermoplastic materials, such as polytetrafluoroethylene (PTFE). NOTE ISO 16589 is complementary to ISO 6194 which covers elastomeric seals. This part of the standard specifies general performance tests which can be used for seal qualification purposes. Materials quality control, dynamic testing and supplementary low temperature testing requirements are covered.