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


Modfication in already FFS-III Assessed vessel

Modfication in already FFS-III Assessed vessel

Modfication in already FFS-III Assessed vessel


We have a vessel on ammonical water service as per ASME SECTION VIII DIV 1.
It was imploded due to vacuum. And was restored due to mechanical jacks and pneumatic pressure.
It was derated after FFS level 3 assessment.the study included details of all the welded patches in analysis.

My question is that now we are planning to install platform structure on that platform. For that we need to install few welded patches on external surface.

Its a cladded vessel with CS oitside and SS inside.

In past we have observed cladding detachment in vessel owing to imploded incident.

What hazards are anticipated in welding or installation of structure on vessel.

External thickness and DYE PENETRANT TESTING of surface is satisfactory.

Does it unvalidate The ffs study fea analysis. Or should we check after welding from inside.
Also the quantum of modification is very less in comparison. 200 x 200 plates 10 plates.

Or am i thinking more.

Best regards

RE: Modfication in already FFS-III Assessed vessel

As I mentioned in the other post of this topic, any modifications to your vessel will immediately invalidate the original FFS.

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


White Paper - The Evolving Landscape of Commercial Battery-Powered Trucks
What’s driving the evolving landscape of truck electrification? What are the barriers, motivators and strategies for accelerating the electric transition? What insights and resources are available for today’s design engineers working to achieve industry disruption and evolution? For answers to these and other pertinent questions, read this white paper. Download Now
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

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