hi,
The formula S=((PD/t)/2)-PY can be rearranged within mathematical standards also can be rearranged to reverse calculate different values (incase thats what in needed).
Gentlemen,
The code does not mandate shop hydrostatic testing of piping components nor piping subassemblies as is. hydrostatic testing of components is covered under relevant manufacturing standards.
"As a special case" in the event where the owner needs to hyrotest, 345.2.3 allowed under...