3) A set of criteria to compare the installed pipeline to.
"Simples!ζ"
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"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
What you mean a piping inspection?
For inspection, you can refer to the requirements of relevant inspection section in relevant standards / codes, among those more commonly used are:
process piping; you can refer to ANSI / ASME B31.3,
power piping; ANSI / ASME B31.1
Pipe line; API 1104