Re: Re: elevated temperature hydro when client wants to go to flange limits.

From: <Christopher>
Date: Mon Jan 16 2006 - 00:07:00 EST

On Jan 15, 2006, at 7:50 PM, aluser2 wrote:

> the answer from a constr guy who has done heaps of hydro, nothing else
> for many years for a big contracting is that hydro to the flange limit
> on the offchance the line service will change is nuts.
The whole idea is nuts. Do the numbers with the Code and if the whole thing meets Code hydro accordingly. Why fart around doing a hydro for a phony pressure? The rules for operating at elevated temperatures are simple. Since the test occurs at room temperature where the yield stress is higher that it would be in service, you increase the proof factor by the ratio of the room temperature allowable stress to the service allowable. That puts the stress during hydro to about the same percentage of yield as testing at the service temperature. It can't possibly take long to rework the design calculations to match the maximum flange pressure. Again--why fart around doing half the job? Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=-kVB1fNf50ZetfNU9H97FwTi9QcpijE1yfcVwvSps16wh0wMMs8n6vQErVbbVfex-kJ0zu37EMpb0yzPrgo">chrisw@skypoint.com</a> | this distance" (last words of Gen.

____________________| John Sedgwick, Spotsylvania 1864)

<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a> Received on Mon Jan 16 00:07:00 2006