I'm working in a project where my customer bought used equipment. It has steam supply piping A-53A and A-53B(6", 4", 3", 2", 1" dia. sizes), and condensate return piping (3", 2", 1 1/2", 1") A-53A. I have the following challanges:
1. Piping was cut in certain spool and transported inside crates to be installed in a new location. All these should be checked for wall thicknesses. Is there any standard prosedures for re-assesment and testing of used piping?
2. If I perform stress analysis to confirm piping to be signed to ASME B31-1 what should be taken into considerations?
3. If I need to replace certain spools, does it make any difference welding used piping with new one?
4. Did anyone have experience moving plants and equipment from one place to another? What else do I need to know?

Hope you are not putting your name to the installation as it may end up with you locked up. In order to use old piping you need to know what service life it has seen to date. Temperature and pressure durations. From your point 2 it suggests that you are in unknown territory. Suggest you employ a Company with experience in life assessment.

Some engineering companies take the position that units supplied by others are out of the scope of their responsibility and will not perform any verification of the equipment supplied, other than to ensure that it meets the specifications to which it was supplied.  No stress analysis, for example, would be done on any pipe supplied within such a unit.  Considering an example easier to grasp, say I order an 8" ball valve speced to ANSI#600 with RTJ flanges to use in my pipeline.  We check that its a ball valve to ANSI 600# with RTJ flanges, etc., but I or nobody else will do a stress analysis on tha valve to make sure that the mfgr knew what he was doing when he designed it. If we did, and it passed, but failed later, some courts might hold that we as reviewing engineers should have had some responsibility for later damages.  So, if we notice that it was supplied incorrectly, or with a defect, we advise the client to return it, repair or replace it as required to meet the specs. and recover costs from the other parties involved.  Normally, even if it was your companies responsibility to do necessary repairs, the typical would be to replace the materials to original spec or better, without any further analysis or confirmation that the original equipment design was sufficient.  Anything else, stress analysis of the original design, for example, would only be undertaken by special contract provisions.  Does your auto repair store ensure that your car was designed correctly before they replace a part?

Based on my personal experience I concur with all the above information given with emphasis on getting both insurance companies involved.
There are too many caveats on piping as you describe especially when you mention evidence of some corrosion.  
Lumber kilns don't have a good reputation to start with and the legal eagles are quick to jump on that fact.  The in writing aspect is extremely critical and a witness would be an added benefit.  If your forced into a situation of no refusal just use due diligence like you have shown by asking.

These are kilns not autoclaves?  

Just for curiosity is this a foreign owned mill?

Just a little of what you can run into.
Depending on the quality of steam used for the original installation you could run into areas of erosion corrosion at 10"to 15" above all elbows at elevation changes as I did.  We ended up paying more for inspections than new pipe would have cost.  The least part was that every fitter and welder got mad at me because I couldn't change anyone's mind to buy new pipe and fittings.

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