×
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

API 650 Appendix A weld spacing

API 650 Appendix A weld spacing

API 650 Appendix A weld spacing

(OP)
I've been looking at API 650 table 3-6 for regular style re-pad nozzle elevations. Table 3-6 column 8 footnote d says that the HN dimensions are for Appendix A tanks only. Looking at Appendix A, section A.5.2, all you need to watch out for is 2 1/2 times the shell thickness between toes of welds. These yield different minimum nozzle elevations. For example, for a 4" nozzle, table 3-6 says 9" is the lowest a regualr type nozzle can be but if you calculate per section A.5.2 for a 1/2" shell and 1/2" bottom the number is 6 + .5 + .5 + 2.5 * .5 = 8 1/4". This number gets lower for thinner shells and bottoms. Am I possibly misinterpreting A.5.2? If I am reading A.5.2 correctly, why does table 3-6 have footnote d written as it is?

RE: API 650 Appendix A weld spacing

I believe that column 8 of Table 3-6 provides the minimum centerline nozzle height for App. A tanks and is exclusive of the 2.5 times the shell thickness which is for toe-to-toe requirements between connections (i.e. not including the shell-to-bottom joint).  Section A.5.2 reads that section 3.7.3 does not apply except for the 2 1/2 times the shell thickness at the connection.  Section 3.7.3.3 is an additional condition to this for the shell-to-bottom joint as 3" minimum.   This is how I have interpreted it in the past anyway.  I typically follow Table 3-6 regardless of an App. A design or not unless there are special requirements from the client needing a lower connection. I hope this helps.

RE: API 650 Appendix A weld spacing

(OP)
Ah yes, but the title of table 3-6 is "Minimum dimension between weld toes or weld centerline(1)(3)".  Footnote (3) says that for appendix A tanks the spacing is 2 1/2T "toe to toe of adjacent welds".  This should then include the corner weld.  So it would appear that if a penetration has adequate reinforcing, it can be lower for appendix A tanks.

RE: API 650 Appendix A weld spacing

I can see where you could interpret it that way, however I stand by my interpretation that this does not include the corner weld as it is a special case.  I am taking the conservative route.  This would be a good technical inquiry to send to the API 650 commitee.  

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