How to protect PEX pipes from puncture

Question

I'm replacing the copper pipes in my house and I'm converting the trunk and branch type to home run style using PEX A pipes. I want to protect the pipes in the wall that I'm running them up from the basement to the two bathrooms upstairs on the second floor. I have a total of 10 pipes going upstairs. First I thought of using metal sheet to wrap around the section of the wall that the pipes are going up. The kind that is used for the ducts, but that was too thin and a regular drywall screw went through it without a problem or me noticing that I punctured the metal. Then my next idea was to use 3/4" electric conduit and run my 1/2" PEX pipes in those. It seems like a good idea, but I'm not sure if that would be against any kind of code and if the hot water pipes would be damaged from friction damage as they expand and contract quite a while as I noticed from the pipes that are fixed between the joists in the basement. My plan was to use plastic rings on each end of the electrical conduit to protect the PEX pipes from getting scratched over time and there is a 90 degree bend in each conduit to allow to easily continue with the pipes in the ceiling wall once it enters that section. I was even thinking of using insulating foam sealant to push into the pipe to not to allow the PEX pipe to move around and get damaged from the friction.

Do you guys think that would work?

Thanks for the suggestions and ideas.

Answer 1

Usually around here these pipes are in corrugated plastic conduit. Same for wires.

The conduit is free to move around inside the drywall, so it you drive in a screw (or a drill bit) it will scratch the conduit but it will push it out of the way instead of going through.

Here's an example (European metal drywall studs, not US wood studs, but you get the idea):

Answer 2

The PEX pipe installed in tubes like that doesn't seem to have enough flex-room for the combined heat/pressure cycles it will likely see. I'd look for a thick enough metal plate, maybe scrap, to cover the pipe in the chase - what would work, maybe 18ga steel (.0478")? Something that says 'your nail or screw doesn't belong here. I know your space is tight, but you could cover it with wood or plywood to allow attaching pictures and such. The pipes should 'snake' a bit so they can flex as needed in operation.