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


API 653 / 650 Nozzle Local Discontinuity Code Allowable

API 653 / 650 Nozzle Local Discontinuity Code Allowable

API 653 / 650 Nozzle Local Discontinuity Code Allowable


I have a question regarding API 653 / API 650 that I was hoping someone may be kind enough to answer.

With regard to the maximum allowable stress at shell penetrations, is there any up rating factor over and above the stresses listed from table 4.1 of the code?

I am working a stress analysis of a storage tank and was thinking that there may be some allowed increase for nozzle penetrations etc. similar to the 1.5S, 3S system used under ASME VIII div 2.

It seems nearly impossible to have manways etc. by using the API 653 listed stresses from table 4.1


RE: API 653 / 650 Nozzle Local Discontinuity Code Allowable

Nozzle reinforcement is based on area-replacement methods, and it would generally be assumed that actual peak stresses might be substantially higher than the average allowable stresses. If the nozzle reinforcement complies with the code requirement, there is no code limitation on the actual stresses that can occur.
Similar issues arise at the chime area (for example, a plastic hinge in the floor plate is assumed, but plastic hinge obviously exceeds the allowable stress).
Annex P of API-650 addresses this somewhat with regard to external loading on nozzles.

RE: API 653 / 650 Nozzle Local Discontinuity Code Allowable

Thanks for the response.

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! Already a Member? Login


eBook - Rethink Your PLM
A lot has changed since the 90s. You don't surf the Web using dial-up anymore, so why are you still using a legacy PLM solution that's blocking your ability to innovate? To develop and launch products today, you need a flexible, cloud-based PLM, not a solution that's stuck in the past. Download Now
White Paper - Using Virtualization for IVI and AUTOSAR Consolidation on an ECU
Current approaches used to tackle the complexities of a vehicle’s electrical and electronics (E/E) architecture are both cost prohibitive and lacking in performance. Utilizing virtualization in automotive software architecture provides a better approach. This can be achieved by encapsulating different heterogeneous automotive platforms inside virtual machines running on the same hardware. Download Now
White Paper - The Criticality of the E/E Architecture
Modern vehicles are highly sophisticated systems incorporating electrical, electronic, software and mechanical components. Mechanical systems are giving way to advanced software and electronic devices, driving automakers to innovate and differentiate their vehicles via the electric and electronic (E/E) architecture. As the pace of change accelerates, automotive companies need to evolve their development processes to deliver and maximize the value of these architectures. Download Now

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