Is MPI Mandatory for Group P1 Material after PWHT
Is MPI Mandatory for Group P1 Material after PWHT
(OP)
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
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





RE: Is MPI Mandatory for Group P1 Material after PWHT
RE: Is MPI Mandatory for Group P1 Material after PWHT
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Is MPI Mandatory for Group P1 Material after PWHT
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
RE: Is MPI Mandatory for Group P1 Material after PWHT
Which edition of code are you using and can you confirm the Para reference...
RE: Is MPI Mandatory for Group P1 Material after PWHT
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
RE: Is MPI Mandatory for Group P1 Material after PWHT
RE: Is MPI Mandatory for Group P1 Material after PWHT
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?