Hi,This may seem immature to some. But I am confused.
Referring the Fig II-6-1(b) in ASME B31.1 2007.
The discharge elbow is supported on the main pipe by a dummy(trunion).
Although the dummy pipe is shown insulated the temp of main pipe upto PSV inlet Shall be higher than the dummy pipe.
In the normal operation when the PSV is not discharging wouldn't this create stress in the piping due to differential expansion.
If the support is made of two members i.e. the dummy from elbow rests on the dummy welded to main pipe, the the support contact will be removed when the main pipe heats up.
Can anybody explain how such type of supports actually work or shall be designed.
Regards

I think we can include that support in the analysis and see what happen ...right?

I agree the best way is to model the support and check. but the question is what temperature to consider for the dummy leg. So far I have not found any correct way to guess this temperature. I know I can play with the temperature and make a satisfactory report but what about the real world situation.
But at the same time I understand that this is a very common way to support and I may be missing something in my understanding. I hope our seniors will share their knowledge regarding a correct/better way to design/analayse this case.

Regards
Siv