ASME B31.3- MPI/LPT on Process Piping Butt Welds

[4872]

Dear Friends

Base Material - CS & SS - Process Piping - Dia range from 2" to 6". Weld Porcess - GTAW(Root) SMAW (the rest ).
Based on what I've understood above code does not call for MPI/LPT on Butt/Girth Welds. I've done RT as as required in Project approved NDT Plan. Can some one guide to the code section which call for MPI/LPT? I need your guidance urgently. Thanks

 

[rneill]

B31.3 does not require MPI (MT) nor LPT (PT) on butt/girth welds. Refer to Clause 341.4.1 of ASME B31.3 as this is where examination requirements for piping are specified.

Did your clients specifications require MT or PT ?

 

[4872]

Hi, Rneil, Yes mentioned in the latest ISO Drawings. Job concluded based on Rev 3 which only require to comply with ASME B31.3.But Rev. 4 calls for 20% RT(same as in earlier rev.& Done) + 5%MPI on butt welds
Reinstament done and commissioning completed.
That's the reason. I want to confirm if MPI requirement required according to B31.3.Thanks for prompt reply

 

[rneill]

While, there is no code requirement for MT on butt welds so if this requirement was issued by the client after the contract was awarded, you should go back to them asking for a change order and compensation.

I have never heard of a client asking for MT on butt welds before but there's always a first time. Much more common to ask for MT on fillet welds (e.g., socket welds) - perhaps this was a mistake ?

 

[stanweld]

The Owner's new requirements constitute a change order. Simply clue them in as to the costs of compliance. I am sure you can come to a most profitable cost addition, assuming erection of new scaffolding, removal of insulation, removal of paint and repainting, etc. If the price is high enough, the Owner may rethink his Change.