[MW:8545] RE: 8541] Re: UT or RT for LNG thanks

Hi Redouane,

ASME allows UT in lieu of RT but not as a blanket approval.Under the above code case on a specific case by case basis this change of NDE technique is acceptable. But the UT technique should not be conventional pulse echo type, it has to be state of art digitized UT techniques such as TOFD or Phased Array.

If the design code for the LNG tank is API-620, then the following is the selection criteria of UT in lieu of RT.

7.15.3 Ultrasonic Examination Method

7.15.3.1 Ultrasonic Examination in Lieu of Radiography:-When ultrasonic examination is applied in order to fulfill the requirements of 5.26, Q.7.6, or R.7.6, the provisions of Appendix U shall apply. Appendix U also talks about the NDE techniques mentioned above.

Let me know, if it helps.

Thanks.

Pradip Goswami,P.Eng.,IWE.
Welding & Metallurgical Specialist & Consultant
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net

-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Marcelo P. Soriano Qa/Qc Eng'r.
Sent: Monday, December 06, 2010 12:13 PM
To: Materials & Welding
Subject: [MW:8541] Re: UT or RT for LNG thanks

try to check your project specs i am sure that is mention there the limitation of rt and ut. some points is base in the thickness of material.

marcelo

On Dec 6, 6:50 am, manoj vernekar <manojverne...@gmail.com> wrote:
> Hi
>
> NDT requirements should be  clearly specified in client specification.
> Shell requirement is 100% RT and 100% Tee and long seam regards
>
> manoj
>
>
>
>
>
>
>
>
>
> On Sun, Dec 5, 2010 at 10:01 PM, Brl Pp <refazosa...@gmail.com> wrote:
> > Good morning for all,
>
> > This preocupation is for LNG thanks (120 000 m3 capacity).
>
> > As per the contract and procedure, the radiography test (RT) is
> > required. My contractor needs to do the ultrasonic test (UT).
>
> > My question is:
> > To do the ultrasonic test (UT) or the radiography test (RT)?
>
> > Tanks in advance and have a nice day.
>
> > Redouane (Project engineer)
> > Algeria
>
> > --
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>
> --
> Manoj.Vernekar

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