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

MAWP for nozzle loads and vessel supports

MAWP for nozzle loads and vessel supports

MAWP for nozzle loads and vessel supports

Hello everone,
So far I have not found any design of pressure vessels and heat exchangers with the condideration of using MAWP to analyze the nozzle loads and the support loads on the vessel. Even if the MAWP was higher than the design pressure indicated in the calculation report, but it was still used the design pressure for nozzle external loads and support calculation. This may be because it has no option provided by the software for using MWAP to analyze a nozzle loads and vessel supports except a designer use the MAWP to replace the design pressure and rerun the whole calculation again. In this case, I think that the two design reports to be provided, one is based on the design pressure and another is the MAWP.
I am not so sure if it is only me with such issue. Welcome peers to share your experience here. Anybody has had the experience in using the MAWP to nanalyze nozzle loads and vessel supports in your real design before? Or as a reviewer/inspector, you noted that some design had considered the MAWP into the nozzle loads and support design, welcome to share the cases here.

RE: MAWP for nozzle loads and vessel supports

Which software are you using for that matter?

COMPRESS has this option of evaluating nozzle loads based on MAWP. It uses calculated nozzle MAWP and uses the same to perform nozzle piping laods as per WRC 537 (or WRC 107).



RE: MAWP for nozzle loads and vessel supports

I am at a loss to understand how the MAWP directly affects the analysis and design of pressure vessel supports.

(Of course this is aside from the usage of the ancient Zick methodology for the design of saddles on horizontal vessels)

Assuming the rest of the vessel is properly designed and meets ASME requirements, how does a change in the MAWP specifically affect the design of the supports ?

Explain what you mean .....

How does an increase in MAWP affect the following ???

- Pressure vessel legs on vertical vessels
- Pressure vessel lugs on vertical vessels
- Pressure vessel skirts on vertical vessels
- Pressure vessel lifting lugs

Sr. Process Engineer

RE: MAWP for nozzle loads and vessel supports

@MJCronin (Mechanical)

I cannot explain all at once, but I can explain the effect on saddle (As per Zick's Analysis)

In the zick analysis check is there are two check for longitudinal stress between saddles.
1) Compressive Stresses
2) Tensile Streses

There will be no direct effect on the compressive stresses. But as far as the tensile stresses are concerned, they do depend upon pressure, i,e,

Sp = P x R / (2 x t)

In this equation if you Put P as an MAWP instead of design pressure, the reasult will definitely show more induced longitudinal stresses.



RE: MAWP for nozzle loads and vessel supports

MJCronin, it generally has to do with the thickness of the main shell elements above what is required for pressure. As MAWP is above design pressure, less excess thickness is available to resist external loads.



The problem with sloppy work is that the supply FAR EXCEEDS the demand

RE: MAWP for nozzle loads and vessel supports

@ali.pk, I use PV Elite. Does it have the option (MAWP) for vessel support by Compress?

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 - Reliability Verification for AI and ML Processors
Artificial intelligence and machine learning are seeing growing adoption in a wide range of applications. ICs used for AI/ML applications are characterized by large parallel processing computation units, high power dissipation, and complex circuitry that can deliver maximum performance within a strict power budget. 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