No they're not clay. We have CCTV and can tell that they're concrete. We actually believe that they're nonreinforced concrete pipe (ASTM C14) which seems to available in the 8"-10" diameter range.
I'm working on a gravity sewer replacement project in which we're replacing existing 8" and 10" concrete sanitary sewer pipes. I assumed that they were RCP, however, in trying to research pipe dimensions I haven't been able to find any information on RCP pipe less than 12" in diameter. Was...
