×
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

Auto-Refrigeration

Auto-Refrigeration

Auto-Refrigeration

(OP)
All,

For a new CS vessel that will have auto-refrigeration, do I just use UCS-66, 67, 68 and 160 to specify the thickness, or shall I go by API 579 and ASME FFS-1 fitness-for-service and develop a minimum allowable temperature ? I do not think I need to go by API 579/ASME FFS-1 for new vessel. What is your opinion ?

RE: Auto-Refrigeration

I think any reference standard to allow the designer to better evaluate design conditions either in or pre-service to avoid brittle fracture is worth it. In this case, you can use the methodology in Part 3 of API 579 to determine a minimum allowable temperature curve.

As a minimum, you can run a sanity check against initial vessel design to evaluate risk.

RE: Auto-Refrigeration

I may just be overly cautious with some wording used but UCS-66, 67,... wouldn't specify thickness. I'd say the order of logic would be as follows:

1) Determine tmin from UG-27 and specify thickness.
2) Define the MDMT (May be using this term inappropriately. I believe I've seen MDMT used as both the stamped minimum temperature the vessel can physically handle and also the minimum temperature that can be encountered during operation/transient conditions. I consider it as more of the former although that could easily be argued.)
3) Use UCS-66, Fig. UCS-66, and relevant sections to determine if the MDMT is acceptable without requiring impact testing.
4) Take any credit from UCS-66.1 as necessary and appropriate.

There's a lot of other steps but here's a very brief overview. Actually Fig. UCS-66.2 has the overview of the logic for this process regarding the MDMT, I'd recommend referring to that.

Thanks,
Ehzin

Was assuming this is a coded vessel given that UCS sections were mentioned. If it's not coded then I suppose using any relevant guidelines regarding MDMT could be acceptable. ASME Section VIII does provide somewhat thorough guidelines.

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