Professionally, I have worked on safety systems on refineries and
I get worried by gas leaks, solid pipe (generally) doesn't leak.
Connections and valve stems are potential leaks. Copper pipe
connections can be made by metal ferrules (incidentally, the type used
industrially are totally different to the boaty type - they would not
be allowed). Valves stems have to have soft packing which will
degenerate with time causing leaks.
Copper pipe has to be supported at regular intervals, and where it
passes through bulkheads, protected from chafe (a god dollop of
silicone sealant is OK)
My preferences are to keep these to a minimum, and they should be in
freely ventilated areas. On Judicious I have (with some difficulty)
used a copper pipe in one piece all the way from the cylinder to the
cooker. According to the UK Code of Practice I should have a cutoff
valve at the cooker but I don't. If I had a fire at the cooker I
could not reach that valve anyway. I just use the valve on the