This final rule allows some exception to the requirements to nondestructively test 100 percent of the girth welds in certain onshore locations. In certain cases where 100 percent testing is impacticable, testing less than 100 percent is allowed if at least 90 percent is tested. An operator who avails itself of the "90 percent testing" rule must determine that, under the circumstances, nondestructive testing is impracticable for each weld not tested.