×
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 653 - Repair of Tank Shell - Code Interpretation

API 653 - Repair of Tank Shell - Code Interpretation

API 653 - Repair of Tank Shell - Code Interpretation

(OP)
Hello all! I just performed an "Out-of-Service" inspection of a Fuel Oil tank for one of my clients. The examination of the shell yielded some wall thickness measurements that are in violation of the calculated minimum required wall thickness for that course. I am familiar with making repairs according to the API 653 Standard but but repair is being slightly complicated by what may be an incorrect interpretation on my behalf:

First off, some background/design info on the tank...Nominal Diameter is 36.25-feet, Fill Height is 42-feet, Material is A283, Grade C (23,600psi, max. allowable stress), Joint Efficiency is 0.85 (according to Table 4.2, 1969 Basic Standard), Nominal Wall Thickness is 0.250-inches (1/4-inch).

This repair would be pretty simple and straight forward...Cut and roll a tombstone shaped (2-inch radius upper corners) piece of plate large enough to extend past the area of concern by at least 1-inch and attach it to the shell using a full fillet weld around the perimeter. However, my interpretation of articles 9.3.3.1 and 9.3.4.2 are giving me some trouble. They both indicate that I need to calculate the thickness of my repair plate using a joint efficiency of 0.35 and when I do that, I come up with a number that exceeds a 30% or 0.125-inch (1/8-inch) increase of the shell plate material, which is not allowed according to 9.3.3.2 and 9.3.4.3.

Any advice?

RE: API 653 - Repair of Tank Shell - Code Interpretation

My interpretation is is that you can't use a lap patch for your repair in this case. It does not meet the API 653 Code required conditions with your tank's parameters. You will have to cut the shell and install an inlay patch.

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