12.3.5 Magnetic-particle examination shall be performed on all pressureretaining welds. If accessible, the back side of the root pass shall be examined after being prepared for final welding. Both sides of accessible completed welds shall be examined. 12.3.6 Magnetic-particle examination shall be performed on all pressureboundary attachment welds. 12.3.7 Magnetic-particle examination shall be performed on areas where temporary lugs have been removed. These areas shall be prepared by grinding them before the examination. 12.3.8 After the hydrostatic test, a magnetic-particle examination shall be performed on all external pressure-retaining welds and all internal nozzle welds that are accessible without disassembling the heat exchanger.
Charlie Chong/ Fion Zhang