"....hugely overcosted designs..."

How much does a repad cost?

For shell & tube exchanger and pressure vessels, we issue a standard force/moment based on nozzle size as part of the inquiry. I don't remember the exact basis for them, but we are generally able to meet them w/o a lot of weird routings and it's a rare thing to have the vendor come back and say they can't meet them.

Quite frankly, we generally can't wait for firm vendor data to do stress analysis. The vessel/exchanger engineers issue a basic outline drawing showing nozzle locations and orientations to the vendor. Piping design starts building the piping model from that drawing and we start working those ISO's.

Maybe in the "good old days" when you could spend a couple of year engineering a job, you could wait for all the equipment data to be issued before piping and stress got in deep, but today's "fast track" schedules are less tolerant of such things.