PetroStreet

Has there been any practices in place where restricted orifices in critical hydrocarbon services are inspected, and maintained?
If yes, which areas are preferred, and what sort of an inspection frequency or maintenance plan is set in place?

Including any sort of restricted orifice is not a mandatory requirement from any of the piping inspection code, just to clear you on that.
RO itself does not qualify to be a pressure equipment however it is classified as special emphasis piping component meaning can have significant impact on the pressure boundary based upon its performance.
Restricted orifices clearly fit this "special emphasis piping component" because they commonly experience:
High velocity erosion
Jet impingement downstream
Flashing / cavitation
Plugging
Vibration fatigue
Having said that, and focusing on critical systems, I would say that it is a good idea to have an inspection & maintenance program in-place but that would be all intrusive.
Screening would still be required to be performed at operations engineer level to identify the critical ones, keep monitoring their performance in terms of process parameters, and flag for their inspection during opportunities.

irish,
In your own experience do you confirm having such a plan in place, and being followed as well?
Please share some specific details if any.

To be honest, what I could recall is an isolated request we received from operations where they suspected erosion /corrosion happening, and their doubt was confirmed with an inspection made during the shutdown. That particular orifice was then subjected to a replacement frequency.

ww2i wrote: 09 Feb 2026, 08:27 irish,
In your own experience do you confirm having such a plan in place, and being followed as well?
Please share some specific details if any.

So it is the assessment call but not a sort of some recommended good practice. Thanks.

Yes, there has not been any mandatory inspection /maintenance listed for RO however, as part of piping component, in case, some damage is anticipated, an inspection task can be introduced, and linked with the opportunity. Not only, with a damaged RO, process may get its own effects, mechanical damages are possible as well.
Consider the piece, a piping component following API 570.