×
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

Tank floor inspection

Tank floor inspection

Tank floor inspection

(OP)
Dear friends I haven´t been able to find in API 650 or 653 the tolerances for tank floor´s flatness, any one can help me?

RE: Tank floor inspection

API-653 Appendix B has EVERYTHING you need to know about the flatness of a tank bottom. It has everything from edge settlement to localized bulges away from the shell. All acceptance criteria and calculations are given as well.

Hope this is what you're looking for.

RE: Tank floor inspection

(OP)
Thank you , I will ask for help from my NDT inspector because contractualy it only aplies API 650 for contruction, 653 is for repair, does it also aply for this case?

RE: Tank floor inspection

(OP)
Does B.3.3 "Internal bottom settlements or bulges", is the one that aplies? in our case the bulge is manifested along the whole plate´s 20 feet, wich means the plates were not properly inspected before installing. Is B.3.3 the section that aplies? been B = 0.37R, again in our case the bulge has an R = 6/2 feet, so B=0.37*(6/2*12)= 13.32 inches, isn´t that too much!!!!!? maybe it will never happen... in our case the bulge is about 1 inch

RE: Tank floor inspection

(OP)
Hi Bonswa
Well, our API inspector accepted my sugestion to use ASTM A 6/A 6M, and the constructor accepted it having to repair, this standard gives 29 mm for this 5/16"x 1800 mm sheet. The matter here was that the material was unaceptable, and ASTM was the spec for this

RE: Tank floor inspection

App. B of API-653 applies to localized settlement or bulges, not to general out-of-plane distortion as occurs in new tank bottoms.

ASTM A6 would apply to the plate before it is cut or welded.  Additional distortion will be generated in processing the plate, and the A6 tolerances would not be applicable to a tank bottom after welding.

One of the tank standards includes a statement that out-of-plane weld distortion equal to 1% of the tank radius is not uncommon.

Usually tank bottoms will have some springy areas where they are not in uniform contact with the subgrade, and these are not objectionable.

RE: Tank floor inspection

(OP)
JStephen:
In:

"One of the tank standards includes a statement that out-of-plane weld distortion equal to 1% of the tank radius is not uncommon."

You mean in API 650?

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