Can design changes to pressure vessels be used to avoid supervision and inspection in this way?
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For pressure vessels that are already in use, the user entity shall submit an application to the design agency to have the DN50 safety valve on the original hydrogenation reactor replaced with a DN40 one, or to have the system take over its function. So, is it necessary for the design firm to recalculate and provide a calculation report? Is re-inspection required? Is it necessary to inform the original inspection unit? Generally, once the design firm stamps its approval, it assumes responsibility for the design. However, in practice, large end-users have considerable influence, and sometimes the design firm is even affiliated with such end-users. Regarding operation under overpressure, some leaders believe it cannot be regulated as there are no legal provisions to that effect. Opinions also vary. Are there any experts who can provide specific advice? Thank you!
Changing the safety valve from DN50 to DN40 requires recalculation. If it meets the requirements, a reducing fitting can be used to connect the original flange to the DN40 safety valve. No supervision is required. If the calculation is not satisfactory, the design unit will not approve it.
The safety valve for DN50 passes the calculations, while that for DN40 may not pass them. A DN40 safety valve can be used only if its calculations show it is compliant. Otherwise, you know------. If the calculation meets the requirements and you still insist on going for supervision and inspection. No one is stopping you either.
The safety valve for DN50 passes the calculations, while that for DN40 may not pass them. A DN40 safety valve can be used only if its calculations show it is compliant. Otherwise, you know------. If the calculation meets the requirements and you still insist on going for supervision and inspection. No one is stopping you either.
It seems the poster is a designer. As a designer, one is now subject to a lifetime responsibility system; it is necessary to act in accordance with laws and regulations, otherwise one will have to bear the consequences of any mistakes. Even if the users or even the leaders of the design team ask you to make changes, you must act in accordance with the law; everyone knows this clearly.
If the calculation is unsatisfactory, there’s no need to say more. If the calculation shows it is feasible, is equipment modification necessary? How high are the costs for the using entity? Just use a reducer directly.
If the safety relief passage becomes smaller, recalculate to determine whether it meets the requirements. No supervision is required.
Now, the user units feel that there is no need to go through this procedure, and the design and manufacturing units share the same view. Even the regulatory authorities consider it unnecessary, but they mainly rely on the opinions of the testing agencies. For testing units, one case requires it while the other does not. There is no concrete basis for the requirement, the regulations are vague, and there are different interpretations. The opinion among those who don’t need it is unanimous: if something goes wrong, the design firm shall take responsibility.
Using unit: Save as much as possible. Manufacturing unit: It’s none of my business. Designing unit: The calculations are satisfactory. Inspection unit: There is no basis for inspection. Supervising unit: The Special Inspection Institute will do; if not, then it won’t work