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.subramanium@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:gajjalla@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.
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