In addition to the code,site condition and material issues, unfortunately the Process commissioning engineer has the final say if the line can be pressure tested by hydro/pneumatic/any other liquid, as they define the type of test to be performed for that fluid process system...not a construction or material engineer.
The apex person to over rule all these is the plant owner's process engineer.
So there is every possiblity that the line need not been performed with any kind of pressure test at all with the right knowledge of the process/piping system. So pnuematic in lieu of hydro due to scarcity of water may not be justified for acceptance, though both tests are intended to ensure the integrity of the system as a whole and of all types of joints of the system.
With regards,
Kannan.
| "Bathula Raghuram \(Mumbai - PIPING\)" <R.Bathula@ticb.com> Sent by: materials-welding@googlegroups.com 16/06/2008 09:43
|
|
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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