×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

pipeline slope
2

pipeline slope

pipeline slope

(OP)
Dear expert;

It's possible and acceptable to make slope (3 degree & length 20 m ) in trench of pipeline instead of cold bend .

Pipe diameter is 12 inches.

Thanks in advance

RE: pipeline slope

Yes. That 3deg you speak of is the maximum alignment change that can be made at a joint without using a cold or hot bend.

Be careful with wall matchup.

RE: pipeline slope

Do you mean 3 degree at a joint or 3 degrees over a 20m length as an elastic bend?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: pipeline slope

Good question.

RE: pipeline slope

(OP)
3 degrees over a 20m length

RE: pipeline slope

It appears that you want to introduce an angular offset in the pipeline. Similar to Miter bends we compare the allowable angle (B31.1).

So if you have sch 40 pipe then allowable angle is 2.31 degrees to consider the welds as normal girth weld.
So in effect the joint becomes non standard and stress intensification factors etc. needs to be established based on relevant code.
So it is better to reduce the offset angle to be within code limit or break the angle offset in 2 stages of approx. 1.5 degrees each.

Engineers, think what we have done to the environment !https://www.linkedin.com/in/goutam-das-59743b30/

RE: pipeline slope

(OP)
we have sch 30 pipe (8.38 mm ).

RE: pipeline slope

(OP)
the Miter bend or angle offset is acceptable in pipeline ?

RE: pipeline slope

Miter bends with angle offsets are acceptable as per B31.1. But in case the angles are above the value given by the above formula the SIF, flexibility factor etc. are to be calculated as per Appendix D but only 90 deg Miter bend values are given. So if the angle is more than 2.07 deg and the bend angle is other than 90 deg then SIF etc. needs to be calculated based on other clauses as per code.
But if angle is less than 2.07 deg then it is regarded as normal girth weld and no special treatment is necessary.

Engineers, think what we have done to the environment !https://www.linkedin.com/in/goutam-das-59743b30/

RE: pipeline slope

I must admit I had never seen that equation, but then I don't use B 31.1 very often.

B 31.4 has a simple limit of 3 degrees which is the max before it becomes a miter or mitre joint.

However 3 degrees over 20m with a 12" (300 ND) pipe is an elastic bend of just over 1000D.

3 degrees is 1/120 of a circle. Therefore circumference of the circle is 120 x 20 = 2400m. Radius of the circle is = (circ/ PI) / 2.

I am pretty sure this won't exceed any stress limits providing the curve / bend is smooth.

At 1000D or more it will simply lie in the trench bottom.

If you think you can accurately cut a 2 degree slope on a 12" pipe then I think you're in the wrong game.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close