This International Standard specifies four methods for the determination of the Vicat softening temperature (VST) of thermoplastic materials: . Method A50 using a force of 10 N and a heating rate of 50 °C/h; . Method B50 using a force of 50 N and a heating rate of 50 °C/h; . Method A120 using a force of 10 N and a heating rate of 120 °C/h; . Method B120 using a force of 50 N and a heating rate of 120 °C/h.