Is a radiographic inspection rate of 20% acceptable for the butt welds of the main body of a 17 cubic meter liquid ammonia storage tank?
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Question – Is a radiographic inspection ratio of 20% acceptable for the butt welds of the main body of a 17 cubic meter liquid ammonia storage tank? Recently, I encountered a liquid ammonia storage tank (DN2000) with a design pressure of 1.93 MPa and a total volume of 17 cubic meters. According to the classification standards of version 09, it should be classified as a Category II container; for welds in Categories A and B, 20% radiographic inspection is permitted, and Grade III is considered acceptable. But I always feel that doing this might be setting a bit low of a standard? I’m a bit confused; I’d really like to ask everyone for advice!
By standard criteria, 20% is acceptable. However, this is liquid ammonia, and the equipment is not large; increasing it to 100% won’t add much in terms of length. From the perspective of improving quality, it’s not a bad idea either.
The standard is the minimum requirement; 100% is recommended
"The standard represents the minimum requirement; it is recommended to aim for 100%. Improving quality within a certain range is certainly a good thing.
Liquid ammonia is flammable and explosive, as well as toxic to humans and animals; even trace leaks are not allowed. Liquid ammonia storage tanks must be 100%
The question is unclear; is it about manufacturing? How to adopt the 09 version of the tolerance specifications?
It should be the 2016 version of the regulations; I wrote down the wrong version number