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


API650 Tank Tolerances

API650 Tank Tolerances

API650 Tank Tolerances

Dear Experts.

We are constructing a 28.4 mtr dia x 17.7mtr hight CS Fixed roof storage tank. Construction is done using Jacking method oe top to bottom construction.

I would like to seek your advise on the Roundness Tolerance. As per API 650 for the size of this tank roundness tolerance is +/- 19mm. As the roundness is measured 300mm from the tank floor on the first strake, we are just checking the radius of each course at 10deg intervals.

My question is if radius of each courses checked outside the tolerance limit the is it still acceptable? as API 650 does not give any roundness tolerance for individual courses?

Thanks in advance

RE: API650 Tank Tolerances

The roundness is only checked at the 300mm level as you note. Roundness of shell above that point is actually checked with the plumbness measurements.

RE: API650 Tank Tolerances

Thanks JStephen,

Referring the API650 on the plumbness, tolerance given in 1/200 of the total height. So if I am doing the top to bottom construction and to check the plumbness at any time during construction is it measured 1/200 of the height of the tank constructed? or is it something else? (Also API 650 indicates plumbness of individual course is limited to flatness and waviness of plate as per ASTM A6M/..... and checking that for 8mm thick x 2400mm wide plate it is around 35mm, but if I go with 1/200 x 2400 which is only 12mm....so I am confused which is right way)

RE: API650 Tank Tolerances

It's 1/200 of the final shell height for overall plumbness.

RE: API650 Tank Tolerances

I don't see any problem to measure the roundness in each course, as matter of fact its convenient matter for construction, the tolerance for plumbness in a individual plate course is in ASTM 6m, and check the peaking and banding before you raise each course.

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!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close