Re: [PipingDesign] Re: Regarding stress check for hydro test

From: <Christopher>
Date: Tue Jan 29 2008 - 21:05:00 EST

On Jan 29, 2008, at 3:21 PM, umesh k.n. wrote:

> A simple hoop stress calc based on code should be sufficient.
> This is to ensure that the design pressure selected for the piping
> class is such that hoop stress during hydrotest pressure (typically
> 1.5 times design pressure) does not exceed code limits.
Sufficient for what? The statement doesn't make sense. The hoop stress at the hydrotest pressure is 1.5 times the hoop stress at the MAWP. If the hoop stress at the MAWP is greater than 2/3 of the allowable material stress, S, the hoop stress during the hydrotest necessarily exceeds the code allowable.

There's no point in figuring the stress at test pressure unless the weight of the contained liquid is significantly greater than the weight of the contents under service conditions. Christopher Wright P.E. |"They couldn't hit an elephant at chrisw@skypoint.com | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/~chrisw/ Received on Tue Jan 29 21:05:00 2008

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