Re: pressure test thoughts

I assure that I have been involved with and charged many profitable hours in re-rating piping systems.

First not all piping systems are stamped nor regulated per se... (Crazy to think about but the truth, in some states a 50PSIG sat steam line of any size may be regulated wheras a 4000PSIG 650F hydrogen cyanide gas line is not regulated)

Second re-rating is not something to be undertaken lightly, and never to be done by unqualified people.

Third my experiences were both in refinery piping systems as well as conventional power plants.

So non-mandatory it may be but it (or practices like it) have been used by may specialists to re-rate piping systems.

This can often times be more readily accomplished for piping than pressure vessels because of the excess wall usually available. By the same token flanges are a problem along with just what condition the system is in and what was it designed to.

Refiners have used this practice for many years getting their plants to be maxed out so as to avoid building new refineries.... (not necessarily a good idea as we all know now).

Sorry to diagree but have made some $$$ at this type of effort

• In PipingDesign@yahoogroups.com, Christopher Wright <chrisw@s...>
  > > Rerating piping systems....
  > I'm taking my cue from the ASME PV Code and the National Board
  > governing repairs. In those Codes rerating only applies to downgrading
  > to reflect certain kinds of degradation. If the Appendix is
  > non-mandatory I don't see how it can apply, since non-mandatory
  > appendices are advisory only. The ASME Code actually applies to new
  > construction only. Once it's stamped, that's it. The National Board has