I want to run a 15mm copper gas pipe from below the hall's suspended floor into a new solid floor in the kitchen. It will be below the surface of the solid floor for 2 metres. I plan to fit 2m of 32 mm plastic drain pipe running upwards at a slight gradient from the entry point below the hall-kitchen doorway to the exit point in the kitchen, behind units. The gas pipe will run through this drainpipe. (I thought of using a 22mm copper sheath, which would be stronger, but might corrode in contact with the concrete, or might expand and crack the concrete)
Does that sound a reasonable way to do it?
Tony