×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

B31.1 Branch Ligaments

B31.1 Branch Ligaments

B31.1 Branch Ligaments

(OP)
Is there a provision in B31.1 that calls on PG-52 or any other section of any other ASME Code in regards to ligaments between multiple branch connections?

--------------------------------
Fitter, happier, more productive

RE: B31.1 Branch Ligaments

Ligaments??? What the heck are you talking about?

prognosis: Lead or Lag

RE: B31.1 Branch Ligaments

(OP)
You've never heard of 'ligaments' mentioned in ASME BPVC? You must not work with that code.

--------------------------------
Fitter, happier, more productive

RE: B31.1 Branch Ligaments

Big Tank,
You are correct, I do not work with the Boiler & Pressure Vessel Code.
The poster was citing ASME B31.1(a Piping Code) and 'multiple branch connections'(a piping term) not the BPVC.
So my question still stands, what is a ligament?

prognosis: Lead or Lag

RE: B31.1 Branch Ligaments

pennpiper,
Have a look in ASME 1 - a ligament is the base metal between the edges of two holes on a pressure part.
Example: a header with multiple branches has ligaments between each of the tube holes.

Big Inch,
Not sure if this helps at all - can't find anything else

Table D-1 Flexibility and Stress Intensification Factors (Cont’d)
(6) The equation applies only if the following conditions are met.
(c) For branch connections in a pipe, the arc distance measured between the centers of adjacent branches along
the surface of the run pipe is not less than three times the sum of their inside radii in the longitudinal direction or is not less than two times the sum of their radii along the circumference of the run pipe.

Cheers,
DD

RE: B31.1 Branch Ligaments

Calculations and reinforcing for affected areas where required

RE: B31.1 Branch Ligaments

(OP)
pennpiper: PG-52 is Section I of BPVC, so I did mention it in the original post. I guess I didn't realize that you wouldn't know that unless you knew that part of the BPVC Code

DekDee: thanks for digging! An engineer at our company that recently left liked to apply Code methodology where the Code allows for 'sound engineering judgement'. In this instance it appears he thickened the wall required in B31.1 by using a ligament efficiency as calculated in Section I in an application where the piping carried water to or from a Section I economizer and there were some branch connections relatively close to one another. This seems alright by me, but I think (as BPVC seems to do) it obscures what's really happening in that area in terms of stress. Since a precedent has been set, I may use the same method where applicable.

GenB: I assume you're describing PG-52? I'm not sure if you're trying to direct me somewhere or......

--------------------------------
Fitter, happier, more productive

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!


Resources