Summary of Technical Requirements for Pressure Vessels (45)

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The regulations regarding welded joints are as follows: 01 For Class A and Class B butt joints of pressure vessels manufactured by welding, a full-thickness penetration weld pattern shall be employed. 02 For the weld joints between the nozzles (flanges) of pressure vessels and the vessel shell, as well as those of jacketed pressure vessels, a fully penetrated weld structure shall be employed if one of the following conditions applies: (1) The pressure vessel contains explosive, extremely hazardous, or highly hazardous media ； (2) Containers requiring pressure and gas-liquid combined pressure tests ； (3) Class III pressure vessels ； (4) Low-temperature pressure vessels ； (5) Pressure vessels subjected to fatigue analysis ； (6) Pressure vessels directly heated by flame ； 03 Except for simple pressure vessels, it is not permitted to reduce the weld joint factor in order to waive the non-destructive testing requirements for pressure vessel products. 04 For pressure vessels with a weld joint coefficient of φ=1.0, Class A and Class B weld joints shall undergo 100% non-destructive testing (RT/UT/TOFD). 05 Cross welds should not be used. 06 The T-joint connecting the spherical head to the cylinder shall be of full penetration design. 07 The connection between the conical shell and the cylinder should adopt a fully penetrative structure. 08 When using analytical methods to reinforce the calculations, full-thickness welds across the cross-section should be employed to ensure the integrity of the reinforced structure.