ASME Section III ND vs NC piping

[ArunavaSinha]

In one of our projects, piping designed as per ASME Section III ND is used for System A (say) whereas piping designed as per ASME Section III NC is used for System B. Due to some procurement issues, ASME Section III NC piping procured is less than required. Can we use piping qualified as per ASME Section III ND inplace of ASME Section III NC piping (for System B)?

If not, the what additional qualifications / testing we have do for ASME Section III ND piping to use inplace of ASME Section III NC piping?

Thanks in advance

 

[jpankask]

No, you cannot simply interchange the piping. If you want to use ND piping in System B, you would need to perform an evaluation that downgrades the System B piping...which is probably not likely to be successful, or else the system would have been designed to ND requirements already. There isn't really any additional testing you can do on the piping to show it's equivalent to Class 2 piping. The differences between Class 2 and Class 3 piping start back in the manufacturing process and is carried through to the paperwork/certification that comes with the piping.

 

[ArunavaSinha]

Thnks jpankask. Can u please elaborate how class 2 and class 3 piping differ in their manufacturing process

 

[jpankask]

NC and ND have specific requirements for material content and strength. For most of the material types covered by Section III, they are likely the same, but for some of the materials, there might be slight differences between NC and ND. The Code typically specifies a range of, or maximum, content for the elements that make up each alloy. The Code also requires that the products produced in the manufacturing process be stamped and a certificate accompany the materials which provides traceability back to the manufacturing process that the materials comply with the Code requirements.

So, in short, the piping is manufactured the same, but the content of the alloys may not be the same between class 2 and class 3 piping for a given alloy type...and the paperwork that accompanies the class 2 and class 3 components may not be the same. If you were going the other way, i.e. trying to use class 2 materials in a class 3 application, that typically is not to difficult (though you would still need to evaluate it), but in a nuclear application, use of class 3 components in a class 2 application is much more difficult. It sounds like maybe you need to get involved with somebody who knows the ASME Code requirements and works with the Code more. There are several companies, but one company we have worked with quite a bit on ASME Code issues is Structural Integrity Associates, Inc. They have many Code experts and could probably help you with an evaluation you're looking for, if you have no remedy available to procure the Class 2 materials you need.

 

[EdStainless]

Even in cases where manufacturing methods and composition are the same for both, there are cases where some of the testing required needs to be done before you get to the final product.
Most 'upgrade' (they don't use that word any longer, but I forget the current term) paths require chemical and destructive testing of each piece.
You need to read the Code sections, in some cases there are even differences in quality system and documentation requirements.

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P.E. Metallurgy, Plymouth Tube