Are welds of categories A and B in the shell side of fixed-tube plate heat exchangers required to undergo 100% RT non-destructive testing?
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Guys, is 100% RT non-destructive testing required for welds of categories A and B in the shell side of fixed-tube plate heat exchangers? Is it because of this provision in the fixed capacity regulations?
Moreover, the fixed capacity regulations require that details such as the calculated thickness of equipment that cannot be inspected internally due to structural reasons be indicated on the general layout diagram; however, I have never done this for heat exchangers, only for small devices
Yes, in accordance with the safety and quality requirements for fixed-tube-sheet heat exchangers, welds of types A and B in the shell side generally require 100% radiographic testing (RT) as a non-destructive testing method. This is mainly to ensure the integrity and reliability of the welds, preventing leaks or other potential structural problems. Whether 100% RT must be implemented specifically still requires reference to the requirements of relevant specifications or standards. .
Yes, the question is whether everyone follows this practice; I see that many design institutes do not implement this requirement
According to the guidelines for dealing with issues related to pressure vessels, surface inspection is required during use when such inspection cannot be carried out; in such cases, 100% RT inspection is necessary for welds of types A and B. Fixed-tube-sheet heat exchangers fall into this category. However, we did not follow this requirement when designing fixed-tube-sheet heat exchangers. My reasoning is that corrosion allowance is generally not considered for the heat exchange tubes in heat exchangers, and the service life of these tubes is also relatively short; therefore, there is no need to give excessive consideration to the requirement of conducting internal inspections on the shell side after it has been in use.
In practice, whether to carry out 100% RT non-destructive testing may vary depending on the design institute, project requirements, cost considerations, as well as the specific regulations or standards in effect. Some design institutes may choose not to conduct 100% RT testing based on the specific conditions of the project and risk assessment. However, to ensure safety and the long-term reliability of the equipment, it is highly recommended to follow industry best practices and relevant standards for comprehensive testing. If it is found that the design institute has not implemented this requirement, one can ask them for the specific reasons or basis, to ensure that safety requirements are met. .
Oh, it seems that this requirement isn’t applied to the shell side of fixed-tube plate heat exchangers either, which is a bit strange. No corresponding term was found in GB/T151-2014 either.