B31.3 328.2.2 vs sWPS (AWS)

Date 12-20-2011 16:52 Edited 12-20-2011 16:54

You have to read the limitations of the SWPS and compare them to the requirements of the construction code.

It sounds like your piping system may be rated as a high pressure piping system under the auspices of B31.3. I don't believe SWPSs are permitted for that category of piping under B31.3 because they are not qualified with notch toughness. In addition, B31.3 requires the contractor to qualify their own procedures, qualification by others is not permitted, plus the qualification has to be performed using materials of the same specification as that to be used in fabrication.

The excerpts included below are from an earlier edition of B31.3, but I don't believe these requirements have changed. You can easily reference the same articles in the code edition you are using for your project.

Best regards - Al

B31-3HighPressure-ProhibAWSSWP20-Dec-2011.jpg (106k)

By fschweighardt (***)

Date 12-20-2011 21:02 Edited 12-20-2011 21:58

As far as B31.3:2010 is concerned, (K300) a high pressure system is one that exceeds the ASME B16.5(undated in code) Class 2500 pressure rating for the design temp and material group. As always the client can specify the use of CHapter IX of 31.3 whenever they want. Not sure what you mean when you reference class 300 vs class 3000 in your post

Edit, I see now from your other post the code reference, and sure enough, Procedure Qual by others, which an SWPS is, is not allowed on design pressures exceeding the Class 300 rating in B16.5.
However, in B16.5, using a group 1.1 material at 100 degrees, a Class 300 rating is 46.6 bar, which is ~690 psi. Have you verified your P-T rating in B16.5?

By jon20013 (*****)

Date 12-20-2011 21:35

Gents, if in fact Chapter IX of B31.3 is required then SWPS may not be used for two reasons:

1). Chapter IX requires impact testing and none of the SWPS I'm aware of have impact tests. And,

2). Chapter IX requires that the actual materials (same grade / spec) as will be welded in production be used in PQR testing.

That said, Class 3000 materials "could" be used and if Chapter IX is not mandated by design then base Code applies, in which case SWPS might be used. I always advise caution when attempting to use SWPS' as nice of tool as they are, there are LOT'S of restrictions placed on using them.