Personally I only use “K” copper under ground services and only “L” tubing above ground for all my copper applications.
For back filling I use clean fill or sand BUT you may also want to consider protecting the copper with coal tar enamel just for added insurance.
The main thing is the back fill should be free from all rocks and other hard materials that can puncture the piping wall.
This is true for all under ground piping applications
» This message has been edited by SylvanLMP on 27 September 2001