i'm looking for some info on grade, marking, and tests required for a53 grade b pipe. i have a cmtr with the grade listed as A500B, A53BNT. below that it notes "BNT= grade B not tested - meets tensil properties ONLY". i'm not use to seeing this on our A53B cmtr's. if anyone could share a little pipe knowledge it would be very helpful. i currently don't have astm a53 at this location.