By the end of the 70's and into the 80's, it was discovered that copper could no longer be used as a means to move natural gas. It was discovered that natural gas will slowly deteriorate copper lines from the inside out. You can no longer use copper lines in any kind of construction.
The biggest problem with copper is that it is soft enough to fracture if it used in any type of situation where there is movement and vibration of the lines.
Joe
