Re: [PipingDesign] Selection of pipe thickness

From: <sviswan@technip.com>
Date: Tue Mar 04 2008 - 04:15:00 EST

Siva,

You have something on your mind but not able to express what it is. That seems to be the problem here.

Why don't you simply do a wall thickness calculation on a Excel sheet and verify it yourself? if you are not able to find it out from, whoever did it.

Use the system Design pressures, allowable stresses corresponding to the temperatures for the material, corrosion allowance required and the mill tolerances for the pipe. Then you might be able draw an informed 'logical' inference.

Sajit

              sivakumar
              shenbagaraman
              <vssk2001@yahoo.c                                          To
              om>                       PipingDesign@yahoogroups.com
              Sent by:                                                   cc
              PipingDesign@yaho
              ogroups.com                                           Subject
                                        Re: [PipingDesign] Selection of
                                        pipe thickness
              04/03/2008 10:54
              AM


              Please respond to
              PipingDesign@yaho
                 ogroups.com

Dear Mr.Christopher,

Thanks for your immediate reply.

I wish to few examples , I found mistakes in Spec.

1. For a particular spec lesser schedule is used for small bore and higher schedule for big bore. Ex Sch 80 for 1"and Sch 100 for 16". 2.Lower schedule for pipe and higher schedule for WN flanges. For example sch 80 for pipe and sch 160 for WN flanges.

I could understand by logically this is not correct. I can not take it to client notice, if I don't know the exact selection by Engineering. I want your help in that aspect.

Thanks

Regards

S.Siva kumar

• Original Message ---- From: Christopher Wright <chrisw@skypoint.com> To: PipingDesign@yahoogroups.com Sent: Tuesday, March 4, 2008 1:52:56 PM Subject: Re: [PipingDesign] Selection of pipe thickness

On Mar 3, 2008, at 11:28 PM, sivakumar shenbagaraman wrote:

> I am working as piping planning engineer. We are using standard
> specification given by client for making isometrics. Some times I
> found mistakes in specification regarding schedules. How I can
> select pipe schedules, if I know operating pressure , temperature
> and corrosion allowance. If anybody can give table form it will be
> helpful.

Your first best approach is to inform your client about the mistakes. You don't want to be in the position of taking exception to your client's specification without getting permission. The only way to specify pipe wall thickness is by application of the pertinent Code rules for the particular pressure and temperature required.

I'm really dying to know how you can tell there's a mistake in the specification if you don't know how to specify the correct pipe size.

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/

---

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Save a tree...please don't print this e-mail unless you really need to. Received on Tue Mar 04 04:15:00 2008