With floating ball valves the ball moves to the downstream seat. Higher differential pressures result in higher valve torques. For small valves the effect of the differential pressure is minimal when compared to the assembly stress on the valve seats and stem seal. As a result the torque basically remains constant for the operating differential pressure of the valve body
Personal performing NDT are trained and Qualified to EN 473 /ASNT-SNT-TC-1A. Every valve is subject to a pressure test in accordance with the standard API 598 or BS 6755 Part 1. The rated pressure for the applicable pressure class is in accordance with ANSI B.16.34 / EN 12516-1-2.