Butt fusion of HDPE or MDPE replacement pipe is typically carried out prior to the bursting operation, so that all fused joints can be chlorinated (for water lines), checked, and tested. The pipe should not be dragged over the ground, and rollers, pipe cutouts, or slings should be used for both insertion and transportation of the pipe. The ends of water or gas pipes should be capped to prevent the entry of contaminants into the pipe.