Re: Design Temp. & Pressure!!

From: <Christopher>
Date: Thu Apr 04 2002 - 12:37:00 EST

>My query is as follows:

What you need to do is verify the design under the all the temperature and pressure combinations you're expecting. That includes everything. If you have a lot of combinations, you can start by constructing a table in Excel of the ratio of allowable stress at various temperatures to the expected pressure at those temperatures. That ratio is proportional to the ratio of pipe diameter to required thickness. Put these ratios in the top two rows of the table. The lowest value of that ratio reflects the maximum required thickness and the corresponding pressure temperature point will govern the pipe wall selection.

If different portions of the piping network have different operating conditions you can put those pressures in subsequent rows and calculate new stress/pressure ratios for each section.

It'll take you about 45 minutes to make up the chart including looking up the allowable at various temperatures. If you need to interpolate for intermediate temperatures, build that into the spreadsheet. Once you know the worst case you can proceed with actual pipe wall from there. selection from there.

Christopher Wright P.E. |"They couldn't hit an elephant from <a href="/group/PipingDesign/post?postID=_gaQ58sqc-3y6fklPPYYsKLSje3ukcskBe-jwO2yzNbaPTwpS2R7lMvUBUfy2c7jNfM4TZySus03SUC_i2I">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 Thu Apr 04 12:37:00 2002