What is the purpose of this integrity study? Are you trying to get to the root of failures?
Piping failures are due to process parameters. Erosion is from velocity, quality, etc. Corrosion is from air, carbonic acid, poor chemical treatment. The same companies that offer steam trap monitoring services are usually able to perform these evaluations. In house evaluation by a reasonably experienced process engineer is able to identify root cause of many failures related to erosion and corrosion. An example is the calculation of mixed phase velocity downstream of a steam trap which any process engineer is expected to be able to do, and a common failure location.
Best wishes,
Sshep