1104 test are usually 12 inch or 8 inch. If you test a welder on 2 or 4 inch you limit them to that diameter. So root undercut can be physically measured. BUt if you are using RT to qualify a welder, the test can be busted if there is IP or BT even if the discontunity is acceptable. When qualifying a welder, it comes doen to no IP no BT.
BABRT's