Is MPI Mandatory for Group P1 Material after PWHT

[4872]

Dear Friends
Project - Conversion of Tanker Vesel into FPSO Platform
Material Group 1- ASTM A106-B x 6" x 21.95thk ( Process Piping )
Weld Process - GTAW / SMAW. Applicable Code-ASME B31.3
Upon completion of PWHT/Hardness Test , RT Done- It passed. Did not do MPI.
The purpose of MPI is to detect Surface/Sub-Surface Discontinuities which could be missed out by RT.
But here I'm working with Plain Carbon Steel.
Is it mandatory to do MPI?. Where I can find this requirement in ASME B31.3 or in any other ASME codes.
I'ne gone through Chapter VI, but found nothing about MPI Requirement after PWHT(Stress Relief )
Appreciate prompt guidance and advise

 

[stanweld]

There is no requirement in B31.3 to do MPI after RT of a butt weld.

 

[SJones]

Why are you asking the question? Is it because you are now being requested to justify omission of MT?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[4872]

Dear Mr.SJones
Yes, Based on Para 341.3.1a- I did not carry out MPI. I want to confirm if my understanding is indeed correct. If is mentioned in any other section, pls advise me
Thanks

 

[rneill]

I might be missing something but para 341.3.1a talks about examinations having to be after PWHT for materials in groups P3, P4 and P5. It doesn't have anything to do with defining what examination is required nor does it apply to a P1 material ?

Which edition of code are you using and can you confirm the Para reference...

 

[4872]

Dear Sir
You are absolutely right. It is only talk about P-Nos- 3,4,5 material eaxmination required after PWHT. I assume P1 Material does require any NDT AFTER Stress Relief.
Do you agree with me?
Thanks

 

[metengr]

Yes.

 

[stanweld]

4872,
Your questions regarding ASME B31.3 MPI requirements have been asked and answered herein and in your Thread No. 292-260627. If your Contract requires RT and MPI of P1 pipe butt welds after PWHT, it exceeds B31.3 requirements and you should understand that the writers of that contract know that their requirements exceed those of B31.3. Why then are you pursuing the same line of questioning?