Critical temperature
The critical temperature is calculated as the temperature, for which the utilization of the member is equal to 100%. The value of critical temperature is calculated using iteration procedures. If the member fails for the temperature 20°C, this temperature is signed as a critical one and the calculation stops. As the temperature 350°C is set as a maximum one for members, that belong to the class IV, according to the designing standard, this temperature is considered as a limiting value of the critical temperature for the class IV.