Mmmmm sludge.
Was that put on a new install, however many years ago?
I've seen a pipe just like that in the past few days
I've just ordered a very expensive load of pvc copper coiled pipe for central heating and when I saw that I had that horrible feeling I'd ordered the wrong stuff
Plastic coated copper is just copper, the correct plastic has an extra layer hence being called barrier
Does the barrier stop things getting in or out from the pipe walls? Or have I completely misunderstood? I've seen PEX etc. described as barrier pipe but didn't realise it was a type of pipe construction.