ASME SA material in B31.3 piping 1

[curtis2004]

Hi Everyone,

I couldn't any previous discussions on this issue. The question is: Can we use ASME SA material (for instance, SA-106B instead of A-106B) in B31.3 piping? Is this can be done? If so, what changes shall be followed during design process? What allowable stress values (from Section II or Appendix A of B31.3) do we need to use? Anything else do we need to be aware of?
It is for Normal fluid service, 3" x Sch 40 Natural Gas line.

Thanks,
Curtis

 

[pdiculous963]

Take a look at 323.1.2 of the Code. It has requirements for unlisted materials. As long as you use the allowable stress basis per B31.3 (or a more conservative one) I imagine you would be fine. It may be worth comparing the ASME to ASTM specs. For your case, A-106 and SA-106 are identical.

 

[curtis2004]

pdiculous963,

Thanks for quick response.
As I said, it is 3" natural gas line going to 50 MMBTU/hr burner. Gas pressure is 45 psig, which is well below class 150 flanges rating.
Do I need to do calculations or stress analysis for this one? It is ambient temperature.

Thanks,
Curtis

 

[KoachCSR]

You don't need to do any calculations above what is normally required - the SA material typically comes with more of a "pedigree" in terms of its material traceability, etc (and is generally noticeably more expensive).

 

[curtis2004]

Hi Everyone,

I think, on this particular case it seems it doesn't make a difference. Now, lets changes a bit our conditions. We have 600F Thermal Oil System, with Class 150 flanges on it. Line sizes are from 1" x Sch80 to 14" x Sch40. And someone decided that it is better to use SA-106B material on B31.3 piping. I have the following questions:
1. What stress values are we going to use for calculations and stress analysis? SA-106B Section II ( 17.1 ksi) or A106B B31.3 (changes from 20 to 17.9 ksi).
2. How about SA-234 WPC Section II (17.1 ksi) or B31.3 (changes from 23.3 to 17.9)?
3. How about flanges SA105N vs. A105N? Are they going to have the same rating from B16.5?

Thanks,
Curtis

 

[curtis2004]

One more question:

Is SA-106B is considered really "Unlisted" or not? Certainly, you can't find this material in Appendix A of B31.3. However, there is A106B, and as we know it SA-106 is identical to A106 according to Section II.

I'm not trying to ask these tricky questions. I want just to understand what is best course of action in these circumstances.

Thanks,
Curtis

 

[curtis2004]

Hi KoachCSR,

Yes, it could be more expensive to buy SA-106B instead of A106B. Do you know what is premium for SA material in this case? Is it 10% more, 25% more, or 40% more?

I have seen dual certified material SA-106B/A-106B. I think, it should be SA material, which manufacturer decided to add A certification in order to deal with this kind of stupid situations. Am I right?

Thanks,
Curtis

 

[KoachCSR]

During my past life in the nuclear industry, SA- vs. A- materials were a common encounter. SA- materials were required for all ASME Section III systems due to the additional pedigree they carried with respect to material traceability and additional QC documentation kept with the "batch" during production. A- materials aren't required to maintain such stringent records. In all cases I can think of that I've encountered, the materials were essentially identical. Depending on the material and supply available in the timeframe it was needed, I seem to recall that the SA-material was up to 10x more than the A-material (though it's been a little while, don't quote me on that).

Typically, SA-material is driven by BPV Code requirements; I'd avoid it if you're not dealing with BPV Code piping (unless you just have a pile laying around about to be thrown out).

 

[TGS4]

You mention obtaining allowable stress values from Section II, Part D. Exactly which Table are you using? The allowable stress basis for VIII-1, III, and VIII-2 don't exactly match up with B31.3.

 

[mk3223]

IMO, while the material specifications are the same, the A-106 Spec is for the B31.3 code material, and the SA-106 Spec is for the ASME BPV Code. And, the allowance stress vs temperature for the piping or BPV should be based on the required Code.
Without the extra cost, I won't mind to use dual certified SA/A material. Otherwise, why to pay extra if A material is acceptable for the service.

 

[EdStainless]

In small diameter pipe and tube the majority of product is dual certified. Because often the different in the spec is nothing. And even when there is a difference it is something like a test that optional in ASTM is mandatory in ASME, the added cost is a few %.
Material for Sec III is different, the documentation requirements cost more than the material in most cases. And often the quantities are very low, which adds more cost.

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P.E. Metallurgy, Plymouth Tube

 

[curtis2004]

Hi Everyone,

Thanks for your feedback. Let's decide, for the sake of argument, SA-106B material was already purchased. If it was SA-106B/A-106B dual certified material, there will not be any question, all is straightforward. Let's assume that it is single certified material to SA-106B. Questions are:

1. Is this material can be used for B31.3 pipe? Under what conditions?
2. Is it Listed material or Unlisted?
3. For code calculations and stress analysis what values shall be used? Is it from Section II, Part D, Table 1A or is it from Appendix A, Table A-1?

Regards,
Curtis

 

[EdStainless]

I'll take #3, if you are using SA material then you must use that ref for properties, that is Sec II.
you can't pick and choose mixing rules.

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P.E. Metallurgy, Plymouth Tube

 

[EdStainless]

3323.1.2

323.1.2 Unlisted Materials. Unlisted materials may be used provided they conform to a published specification covering chemistry, physical and mechanical properties, method and process of manufacture, heat treatment, and quality control, and otherwise meet the requirements of this Code. Allowable stresses shall be determined in accordance with the applicable allowable stress basis of this Code or a more conservative basis

I don't see why the SA106B would not be allowed.

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P.E. Metallurgy, Plymouth Tube

 

[TGS4]

Definitely don't use Table 1A. That's for VIII-1. I'd use the same allowable stress as A106.

 

[curtis2004]

I think, if ASME SA-106B spec spells out that it is identical to ASTM A-106B, we can consider this material equivalent of A-106B and consider it as a listed material. Otherwise, it doesn't make sense.
Do you have other opinion on this subject.

Thanks,
Curtis

 

[pdiculous963]

It is six one way half dozen the other. Listed or unlisted, the allowable stress will be the same. Assuming you consider it unlisted, you know the tensile and yield strengths of the SA-106B, so then just apply the correct safety factors on yield and tensile per B31.3 as listed in 323.1.2. You end up with the same allowable stress as A-106B.

 

[curtis2004]

Does anyone have information about a price difference between ASME and ASTM piping materials? What would be a price difference between 4" x Sch40 SA-106B and A106B?

Thanks,
Curtis