Dear All,

We are going to connect new lines to existing headers. Tie-In is either tee or welded branch depending upon piping spec and size of lines. Isolation valves are some time far away from header as per requirement of client and there are several weld joints in between isolation valve and Tie-in. Now we have to define the hydrotest limit. We cannot isolate the portion in between last isolation valve and header and neither we can do hydrotest of exisitng header.
Can any body guide me what to do with that portion of piping. Currently we are asking client to do 100% radiography of those joints. is it appropriate?

I know the question is not related to stress analysis but as there are many helpful seniors here and I have learnt great deal of experience from them, I expect that you people will help me.