RE: Mitre bends

From: <elie>
Date: Thu Jul 28 2005 - 15:49:00 EDT


For hydrocarbon pipeline, you may want to use B31.4, para 841.232 for miter bends.
Cheers,

841.232 Mitered bends are permitted provided the following limitations are met:

(a) In systems intended to operate at 40% or more of the specified minimum yield strength, mitered bends are not permitted. Deflections caused by misalignment up to 3 deg are not considered as miters.

(b) In systems intended to operate at 10% or more but less than 40% of the specified minimum yield strength, the total deflection angle at each miter shall not exceed 12v2 deg. (c) In systems intended to operate at less than 10% of the specified minimum yield strength, the total deflection angle at each miter shall not exceed 90 deg.

(d) In systems intended to operate at 10% or more of the specified minimum yield strength, the minimum distance between miters measured at the crotch shall not be less than one pipe diameter.

(e) Care shall be taken in making mitered joints to provide proper spacing and alignment and full penetration.

John Luf <jcluf@yahoo.com> wrote: See ASME B31.3 for guidance.... its an internationally recognized code for Process Piping....

I will also say get a good fabricator this has all sorts of bad possibilties associated with it... and finally don't forget stress analysis and its impacts on these elbows....

<a href="/group/PipingDesign/post?postID=-oJZeDwhZpRoOBl1MO-Yj2TGfR2tZyZA4M4SB756Gkp9S8M6xExq4wXMkUA_0cmZui-Rkd7Swma6RbyzTv_NjQ">CHAKRABORTYP2@iocl.co.in</a> wrote:

Hi friends,

I would like to know your comments on using Miter / Mitre bends in piping in different conditions like

  1. Limitation, if any, pressure and temperature wise
  2. Limitation, if any, service wise,
  3. limitation, if any, size wise
  4. Any thumb rule.

At present, we need to fabricate two new pipelines on urgent basis. The first one will be within the plant, operating at 12 kg/cm2 pressure, at 200 C temp. The other one is in the offsite (connected to to storage tanks).

Due to non-availability of pipe fittings, we may need to use Miter bends. However, there is some opposition regarding the use of same. Both cases, service fluid is hydrocarbon (SR naphtha to be precise).

Your comments and any guidelines to relevant codes will be highly appreciated.

chakra



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[Non-text portions of this message have been removed] Received on Thu Jul 28 15:49:00 2005

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