Thanks for your all reply.
Above matters we will use welded pipes(ERW) on you guys help.
Because governing code is ANSI B31.1 POWER PIPING and there are no rules confining seamless or welded as I know.
There joint efficiency factor is 0.85 for (ERW).
But I can't handle the corrosion factor...
Can anyone help me I am in the following situation.
I am now considering the piping material as ASTM A53 gr.B and STAINLESS STEEL 304L.
It can be made both seamless and welded type.
I prefer welded type because it costs less money and some of them are as large as 32 inches.
But I am not sure...