There is a power plant inside a Process refinery. Where exactly the ASME B31.1 & ASME B31.3 scope break occurs?

thank you guys for the last reply reg diff b/w ASME B31.1 & B31.3.
Looking forward for your reply guys.
Have a nice day........

It is up to the Owner/Operator as to where the limit is set.
It can be at the Boiler isolation block valves or it can be at the unit battery limits block valves of the Utility plant.