I believe I have seen dozens of YouTube videos and read dozens of blog post about using pvc in greenhouses. The only warning I can recall seeing is to paint it with uv resistant paint or it will get brittle as it is not UV resistant.
Well, I don't know if my pitch was too low or my pit greenhouse is just too warm in the rafters. The painted pvc lost all shape during it's second year.
Thus I am replacing them all with UV resistant conduit of the same size, and the replacing the spine with metal pipe.
Bittersweet, since I will not be using the greenhouse again due to our impending relocation.
I can only hope the walipinies new owner appreciates my efforts.
Happy homesteading!!