Just wondering why the pipes & fitting for my cylinder need to be made from copper? Can they be plastic? Comments Off on Just wondering why the pipes & fitting for my cylinder need to be made from copper? Can they be plastic? 18 Jan 2016 Vote Up 0 Vote Down Answered Public Public Private Technical Anonymous asked January 18, 2016 Hi, Just wondering why the pipes & fitting for my cylinder need to be made from copper? Can they be plastic? 1 answer Vote Up 0 Vote Down Public ⋅ January 20, 2016 Most of the pipe work around your cylinder does not need to be copper. In fact the only copper bit that is actually required is from the outlet to the cylinder to the tempering valve. #1 Please login or Register to Submit Answer