Before you start piping stress calculation, you have to refer to line index ( or called the line classification lists or process line lists) to check design temperature and an operating temperature for line to be checked.Stress analysis shall be carried out on the basis of the design temperature.
Secondly, you have to know requirements base on your project specification such as
Minimum Ambient Temperature. ( TAMIN )
Maximum Ambient Temperature. ( TAMAX )
Maximum Solar Radiation Temperature. ( TS )
Site Installation Temperature. (TAs )
We will use value below in our piping stress analysis tutorials:
TAMIN = 16