Dear Sirs,

I have read most of threads about temperature but I couldn't find clear answer for my question. The question is:
How can we specify ambient(install) temperature for above and underground(buried) piping or pipeline from site condition document for my analysis?

It should be mentioned that site condition document specifies maximum/minimum Absolute Ambient Temperature, Average Maximum/minimum Absolute Ambient Temperature, Maximum/minimum Average Soil Temperature.

For instance, consider a pipeline with below condition

Maximum operating temperature= 35 deg C
Maximum/minimum Absolute Ambient Temperature= 55/-3 Deg C
Average Maximum/minimum Absolute Ambient Temperature= 50/3 Deg C
Maximum/minimum Average Soil Temperature= 33/16 deg C

Which temperature should be considered for above or underground pipeline for stress analysis?

in Special Execution Parameters, you can specify Ambient temperature in C or F,
up to your choise, you may run seperately Max absolute ambient 55c and -3C case for your case

what about UG piping?

To me, ambient temperature is the temperature at which the pipe is cut and installed (hopefully there is one value for both).
It sounds to me like you might be looking for a differing ambient value for above ground piping and underground piping.
CAESAR II has only one ambient for the analysis. If you wish to work in a "second ambient", you can do so using a modifying your temperature values (e.g., T1) to achieve the desired strain. If the system requires a pull or push to button up the final connection, that could modeled as cold spring. But that's pretty extreme for an initial design check.

Thank you Dave for your valuable answer. But I have a doubt:
If I want to perform stress analysis for an underground pipeline or piping, is it an appropriate choice to consider minimum soil temperature as ambient temperature?
Can I consider this temperature(minimum soil) for anchor block force calculation?

If your line operates above this ambient temperature and if you wish to develop a conservative thrust block load (where this thrust load is directly proportional to thermal strain), then a minimum ambient soil temperature should be used.

Dear NRAM,

Normally Site will perform the cutting and installation work during day time. For underground analysis, if I were you my analysis will be as below:

Amb. Temp: 55 DegC
T1: 35 DegC
T2: 33 DegC (to simulate Maximum Average Soil Temperature effect on pipe)
T3: -3 DegC (to simulate the Minimum Absolute Ambient Temperature

T3 will give the most conservative value for thermal expansion. You can also design your thrust block base on this temperature thus giving you the conservative value of Axial Force.