For radiographic or ultrasonic testing, whether fully or partially – what is the basis for making that decision?

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Chapter 10.3 of GB/T 150-2011 \"Pressure Vessels\" provides clear descriptions of the requirements for \"100% radiographic or ultrasonic testing\" and \"partial radiographic or ultrasonic testing\". 100% radiographic or ultrasonic testing: Containers and pressure-bearing components that meet one of the following conditions must have their Class A and Class B weld joints subjected to 100% radiographic or ultrasonic testing using the methods specified in the design documents: a) Class III containers with a design pressure of 1.6 MPa or higher; b) Containers that are tested under pneumatic or gas-liquid combined pressure tests; c) Containers for which the weld joint coefficient is set at 1.0; d) Containers that require internal inspection after use but for which such inspection is not possible; e) Containers holding extremely hazardous or highly hazardous substances; f) Cryogenic containers with a design temperature below -40°C or weld joint thickness greater than 25 mm; g) Weld joints of austenitic stainless steel, carbon steel, Q345R, Q370R, and related forgings with a thickness greater than 30 mm; h) Weld joints of 18MnMoNbR, 13MnNiMoR, 12MnNiVR, and related forgings with a thickness greater than 20 mm; i) Weld joints of 15CrMoR, 14Cr1MoR, 08Ni3DR, austenitic-ferritic stainless steel, and related forgings with a thickness greater than 16 mm; j) Containers made of ferritic stainless steel or other Cr-Mo low-alloy steels; k) Low-alloy steel containers with a minimum standard tensile strength value of Rm ≥ 540 MPa; l) Containers for which 100% testing is required as specified in the drawings. Note: For the pipe connections in the aforementioned containers with a nominal diameter DN ≥ 250 mm, the inspection requirements for pipe-to-pipe butt joints and pipe-to-high-neck flange butt joints are the same as those for Class A and Class B welded joints. Local radiographic or ultrasonic testing: For containers other than those specified above, local radiographic or ultrasonic testing shall be carried out on their Class A and Class B weld joints. The testing method shall be in accordance with the provisions of the design documents. Among them, for low-temperature containers, the inspection length must be no less than 50% of the length of each welding joint, while for non-low-temperature containers it must be no less than 20% of the length of each welding joint; in either case, it must be no less than 250 mm. The areas from a) to e) below, as well as the weld intersection areas, must be inspected 100%. The inspection lengths for areas a), b), c) and the weld intersection areas can be included in the local inspection length. a) All joint seams on the convex head shall be joined first and then shaped; b) Welded joints that are covered by reinforcement rings, supports, gaskets, internal components, etc.; c) Welded joints within a range whose shortest length along the container surface from the center of the opening equals the diameter of the opening, for no additional reinforcement is required as per 6.1.3 of GB150.3-2011; d) Welded joints where embedded connections are joined to cylinders or heads; e) Butt joints between pipes with a nominal diameter DN ≥ 250 mm that are subjected to external loads, as well as butt joints between pipes and high-neck flanges. Note: After testing in accordance with the provisions of this article, the manufacturing unit remains responsible for the quality of the untested parts. However, further testing may reveal minor defects such as a small number of pores that do not pose a threat to the container’s safety; if even these are not permitted, then 100% radiographic or ultrasonic testing should be chosen. Others 1. Nominal diameter DN