Friday, June 20, 2008

[MW:876] Re: 867] pressure testing - with attachment

Dear Mr. Subramanium,

Please note that RT or any NDT cannot replace Hydro or Pneumatic test.
It can only certify the welded joint, not the whole pipe line.

R. Bose

On Jun 16, 10:21 am, "shiva.subramanium" <shiva.subraman...@wsiko.com>
wrote:
> Dear Members, Mr. Surya and Mr. Raghuram
>
> Due to water problem, you cannot go for pneumatic test based on TP = 110% of
> DP) because the hazard of energy release.
>
> Just calculate the pneumatic pressure for the system
>
> Hydrotest = 60 KG/cm2, so design pressure is around 40 Kg/cm2
>
> For pneumatic test, pressure shall be around 44 kg/cm2.
>
> Imagine the hazard of energy release with reference to the
> attachment(attached previous message of Criticality of Hydrotest pressure vs
> pneumatic pressure)
>
> So, better you can go for 100% RT/UT for all Butt joints and PT/MPT for
> attachment weld as per B31.3 para 345.9.
>
> S. Siva Subramanian
> World Services Italia S.p.A., Kuwait Operations,
> P.O. Box : 28928 - Safat : 13151 - Kuwait.
> Tel : +965 3262945 / 3260338 / 3263987 / 3263691/92, Ext.\ 207
> Mobile - 00965 632 7395
> E-mail :  shiva.subraman...@wsiko.com
>
>
>
> -----Original Message-----
> From: materials-welding@googlegroups.com
>
> [mailto:materials-welding@googlegroups.com] On Behalf Of Bathula Raghuram
> (Mumbai - PIPING)
> Sent: Monday, June 16, 2008 10:44 AM
> To: materials-welding@googlegroups.com
> Subject: [MW:867] pressure testing
>
> Assuming your design code is B31.3, refer para 345 for the creteria (TP
> is 110% of DP)
>
> Also refer earlier message posted in this group titled  "Criticality of
> Pneumatic pressure test vs Hydrostatic on piping system"
> we should always remember that is necessary to evaluate
> the design aspects of material selection for piping lines to be
> submitted to pneumatic test: in these cases ASME B 31.3 require that the
> materials be guaranteed against their brittleness at the ambient
> temperature during pneumatic test.
> Typical cases are the plants where the ambient temperature could reach
> even minus 50^C (e.g. some parts of Russia).
>
> -----Original Message-----
> From: gajjalla surya prakash [mailto:gajja...@gmail.com]
> Sent: Monday, June 16, 2008 12:32 PM
> To: materials-welding@googlegroups.com
> Subject: pressure testing
>
> dear members,
>
> we are doing hydrotest for the piping systems and now facing the
> problem of water scarcity ,and our customer praposes to perform the
> pneumatic test .
>
> for example hydrotest pressure is 60kg/cm2 what should be the
> pneumatic pressure . where can we get this information.
>
> surya prakash gajjalla.
>
>
>
>  Scanned_ (2).pdf
> 141KDownload- Hide quoted text -
>
> - Show quoted text -

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