Member Login

Remember Me
Forgot Password?
Join Us!

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!

Join Eng-Tips
*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.

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

API 620 verses 650 standard?

API 620 verses 650 standard?

IYO, which standard is the least restrictive in designing a tank?

Appreciate any enlightenment...

RE: API 620 verses 650 standard?

API-650 would generally be used if the pressure fell within its range of coverage.

RE: API 620 verses 650 standard?

I do not believe that you understand either the scope or the applicability of these two standards.

API 650 covers flat-bottomed tanks to a certain maximum pressure and operating temperature.

API 620 covers tanks to higher temperatures and pressures.

There may be some service conditions where either standard may be suitable.

What, in your particular usage of English, do you mean by "least restrictive" ?

Do you mean lowest cost ?  


RE: API 620 verses 650 standard?

Yes, I am not familiar with either of these Standards.

Least restrictive as in lower cost.

I should have found out more information about tank from Engineering Dept before posting.

My appologies...

RE: API 620 verses 650 standard?

Thank you, I was able to obtain the answers I needed upon further study and inquires.

You are correct that 650 covers flat bottom tanks, and 620 also covers flat as well as other shapes.  620 max design temp is 50 degrees F higher than the 200 degrees F of 650.  620 covers up to 15 psi internal and 650 up to 2.5 psi (appendix F becomes applicable in case of internal pressure).  650 is vertical tanks only, 620 is vert and horizontal.


RE: API 620 verses 650 standard?

Note that Appendix M of API-650 goes up to 500 degrees, whereas API-620 is limited to 250.

API-620 may be applied to horizontal tanks, but doesn't actually include any design provisions for them.  Generally, horizontal tanks would be built to ASME code if pressurized or UL standards if not.

Right offhand, I can't think of any reason why one would use API-620 if the tank in question could be built under API-650.

RE: API 620 verses 650 standard?


"I can't think of any reason why one would use API-620 if the tank in question could be built under API-650."

I agree....Tanks designed to API 650 are designed to a very reasonable set of rules. Most flat bottomed tanks in the world are designed to 650 or the foreign equivalent.

On a side note, I would like to add that many horizontal tanks are designed to "almost ASME VIII" code.

Horizontals are designed, inspected, tested to Section VIII, but no code stamp. Design pressure is typically 10-14 psig.

IMHO, There is a hole in the API design rules about low-pressure horizontal tanks.



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