For ASME Class 1 piping analysis, linear variation of through-wall tem perature is Delta T1, but non-linear variation is Delta T2. In Bentley's On Demand "AutoPIPE Nuclear Powered by ADLPIPE" Training Notes (Apr-11 version), whenever the calculated maximum magnitude of Delta T1 has a negative sign, the non-linear through-wall temperature variation is ignored, namely assign Delta T2=0 using the Operating Pressure & Temperature dialog (see pages 80, 121). Can a Technical justification be provided for ignoring non-linear through-wall temperature variation whenever the maximum linear temperature variation is negative?
The short answer is No, there is no technical justification.
The value is the minimum value for T2 calculated by the equation in ASME and it is applied with the minimum value or T1.
Can the value of T2 be -ve…seems the equation cannot give a -ve value or if a -ve value should be considered. The question is for ASME, we would be very interested in their answer.