×
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

Tubesheet to Shell RT Requirements

Tubesheet to Shell RT Requirements

Tubesheet to Shell RT Requirements

(OP)
I am fairly new with the code and am getting confused with joint efficiency and radiography requirements for a heat exchanger I am designing. I have a 12" .375 wall SA312 316L shell which has a weld seam. I was going to use a UW-13.2(h) as my joint design to attach to the tubesheet. The shell would be Category A Type 1 with a 70% efficiency correct? The tubesheet would be category C type 7 per UW-12? I'm confused because I believe that UW-11(4) states that because it is larger that NPS 10 I am required to have spot radiography. That joint type says that RT is N/A. Any insight would be appreciated.

RE: Tubesheet to Shell RT Requirements

Brown129, this is a kind of complicated subject, it will likely take you some time to master it :)

Joint efficiency via RT is usually applied to butt-joints only. For example your Fig UW-13.2 corner joint, and corner joints in general, is assigned an efficiency of 1 if needed. See Table UW-12, Type 7 and Note 5. You are correct it is Cat C.

For other butt joints in the shell, joint efficiency is assigned per Table UW-12 as per the type of joint. A Type 1 joint with no RT would be E = 0.7, as you state.

UW-11(a)(4) is often the source of confusion. It provides exemptions from full RT for certain joints in a vessel that is otherwise full RT'd. This has been discussed numerous times, you might do a site search for more on it.

Shells made of pipe may be treated as seamless if the circumferential seams are spot RT'd. See UW-12(d) & (e).

Except as limited by Table UW-12, the joint category and the joint efficiency are not related.

You might also see the examples in Appendix L.

Regards,

Mike

RE: Tubesheet to Shell RT Requirements

Taking a step back toward the more obvious: you might want to talk with someone that performs radiography. Corner joints generally don't yield good x-ray results. It's very uncommon for these types of joints to be x-rayed.

I'm sorry if that's TOO obvious, but you never know. Not everyone has the opportunity to see these types of details on the production floor.

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

RE: Tubesheet to Shell RT Requirements

BigTank has a good point. It was some time befoe I understood that.

Regards,

Mike

RE: Tubesheet to Shell RT Requirements

I agree with the answers above, but I just thought I'd add a couple comments.

Quote (SnTMan)

Shells made of pipe may be treated as seamless if the circumferential seams are spot RT'd. See UW-12(d) & (e).
To add to the comment, per UW-12(d) & (e), the joint efficiency on the shell would be 1.0 if UW-11(a)(5)(b) are met (which would not be the case of the above since there are no circumferential seams to shoot), and 0.85 if UW-11(a)(5)(b) are not met.

Quote (Brown129)

I'm confused because I believe that UW-11(4) states that because it is larger that NPS 10 I am required to have spot radiography.

Also, Brown129, the exemption from radiography for butt-joint seams NPS 10 or smaller applies to category B and C seams in nozzle and communicating chambers only, not in the main shell course. If the shell course was NPS 10 or smaller, and there were butt-joint seams (cat. A and/or B), they would require RT also, if the heat exchanger was designed with spot or full radiography.

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