×
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

Max. Allowable stress in B31.1

Max. Allowable stress in B31.1

Max. Allowable stress in B31.1

(OP)
Hi all,

In ASME B31.1 ed. 2004, the SE to be used in the wall thickness calculation formula (para. 104.1.2) has to be taken from Appendix A.

The value given in the Appendix provides "Maximum Allowable Stress Values in tension" and E/F (joint efficiency/cast factor) in separate columns.

In mentioned para. it is said "The value of SE or SF shall not exceed that given in Appendix A, for the respective material and design temperature. These values include the weld joint efficiency E, or the casting factor F".

The question is: for calculating the wall thickness, is it required to multiply the value E given in the table by the maximum allowable stress or not? I mean, S·E or SE?

It seems that the value given in the table already includes this factor as per the mentioned para.

Any help would be highly appreciated.

Thank you all
Rocío


 

RE: Max. Allowable stress in B31.1

Yes, the values in Appendix A of B31.1-2004 already include the joint efficiency factor.

NozzleTwister
Houston, Texas

RE: Max. Allowable stress in B31.1

The allowable stress values given in table A-1 already have the appropriate weld joint efficiency factor taken into account.

You can check this by comparing the allowable stress value for A53 Grade B Seamless pipe with the allowable stress value of A53 Grade B ERW pipe.

A53 Gr. B Seamless E=1, S=15,000 psi
A53 Gr. B ERW  E=0.85, S=12,800 psi
 

RE: Max. Allowable stress in B31.1

(OP)
Thank you very much for your help,

On the other hand, in ASME B31.3 ed.2004, I understand for calculating the wall thickness it is required to multiply the value E/F given in the table by the maximum allowable stress, I mean in this case we have S·E, is it like that?


Thanks in advance,

Rocio  

 

RE: Max. Allowable stress in B31.1

You are correct. Note 1 for appendix A states quite clearly that B31.3 requires modification of the allowable stress by the appropriate factore listed in table A-1B.  

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