×
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

Dual MDMT Rating for P V at Different Temp.

Dual MDMT Rating for P V at Different Temp.

Dual MDMT Rating for P V at Different Temp.

(OP)
I am making alterations to an old pressure vessel and re-rating it. The original U-1A form has a duel MDMT rating which I do not understand. It is rated MAWP 250 PSIG at 125 F with an MDMT of 20 F at 250 PSIG and -40 F at 125 PSIG. I do not see where the USC-66 chart has diferent temps for different pressures. Can someone explain it to me?

Thanks for any help!
Bonkers

RE: Dual MDMT Rating for P V at Different Temp.

bonkers, have you reviewed UCS-66(b)?

Regards,

Mike

RE: Dual MDMT Rating for P V at Different Temp.

Looks like it has two process conditions, at 125F and 40F respectively, which is not unusual. We have a lot of vessels have dual stamping design conditions. The actual MDMT in my interpretation is only 20F and set at the highest design pressure 250 psig, which is also very common practice to do so. From re-rating purpose, MDMT 20 at 250psig is the worst case you shall consider and you can ignore 40F at 125psig even it says it is another MDMT that I think it is just another process condition.

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