Phillip,

I'm sure you wrote that with a skeptical tone to your voice,  but I would urge you to ponder on it a bit.    Do a bit of research on it. Google PVC compressed air failure.  Look at things like this http://www.lascofittings.com/supportcenter/CompressedAir.asp and this http://www.woodweb.com/knowledge_base/Compressed_air_delivery_system.html

I know, it's your life.  But not if anyone else is ever in the building. PVC might work forever with no problems.  But if it fails the results are so horrifying that ... well, just ponder on it a while and maybe consider removing your air system from service before a disaster happens.