Spring Hanger

[Dj364]

Hello eveyone,
I am working on proposal.
just a quick question at what temperature the spring hanger might be required?
I assume 300 C Am I correct?
Thanks in advance for sharing your experience.
Dj.

 

[doberdorks]

Yep, you might need a spring hanger at 300degC. You might also need one at 50degC. or not need one at 500degC.

Depends on what you're trying to hold up, how it's routed and what it's attached to.

 

[JohnBreen]

Hi Dj364,

Your proposal should state that a comprehensive structural analysis (pipe flexibility and stress analysis) should be performed in accordance with whichever B31 Pressure Piping Code is appropriate (mandated by the local jurisdiction) for all piping systems of NPS 3 or larger and all piping systems of temperature/pressure class 150 or higher. The requirements for support design (rigid or resilient supports/hangers) should be based upon this structural analysis. If resilient (spring type - either variable or constant force) pipe supports/hangers are indicated by the structural analysis, the appropriate Code and the Standard of the Manufacturers Standardization Society (MSS-SP-58, MSS-SP-69, MSS-SP-77, MSS-SP-89, and MSS-SP-90) should be referenced.

If you do not truly understand any of the above, seek assistance in writing the proposal.

Regards, John

 

[NozzleTwister]

I shouldn't comment since I'm not contributing....

...but, I once worked for company that handed my a Line List and P&ID's with no more information and asked me for a list of springs with sizes, types and hardware so they could get budget quotes for a proposal.

My suggestion of using factors based on previuos similar jobs they way our legacy company did wasn't taken well.

NozzleTwister
Houston, Texas

 

[Dj364]

Thanks doberdorks, john
John, I understood that we need to perform stress analysis at the proposal stage?
I agree to perform only for very critical lines, lines where we might need such expansion joint or spring hanger. that s why I am asking from what temperature the spring hanger or support might be required.

I don t have such experience and knowledge as you do, please could you put some light on what you meant...
Thanks in advance.
Dj.

 

[DSB123]

NozzleTwister,
Your experience does not surprise me. I have come across a situation where a Project Manager expected a bulk MTO to be taken from a set of P&ID's.No layouts being available.

 

[doberdorks]

Dj,

What we're trying to say is "you don't have enough information to put together that proposal".

What is the proposal for? Engineering? Design Build?
Do you want a low number to get a job, a realistic number, or a high number for budgeting?

What stage is it at?

Really, in all honesty, direction should be coming from those more experienced at your company, message boards are more for a "second opinion" -- as no one on the boards has any idea what you're really trying to accomplish, we really can't answer you're question here.

My personal opinion is that you need to go to your supervisor and ask "how do you expect me to do this" Perhaps at that point you'll have stuff explained or be directed to company resources.

Whatever you do, I'd suggest you document your reasoning even if it was just "complete wild guess due to lack of information".

Shannon


Orig message
Dj364 (Mechanical)
25 Jul 07 15:41
Thanks doberdorks, john
John, I understood that we need to perform stress analysis at the proposal stage?
I agree to perform only for very critical lines, lines where we might need such expansion joint or spring hanger. that s why I am asking from what temperature the spring hanger or support might be required.

I don t have such experience and knowledge as you do, please could you put some light on what you meant...
Thanks in advance.

 

[JohnBreen]

Hi DJ,

I am sorry, I did not mean to suggest that the analysis actually be performed at the proposal stage, rather I am suggesting that before a comprehensive structural analysis is done the requirements for supporting the piping cannot be know with any certainty. You simply cannot know how many (and types of)pipe supports/hangers will be needed until the analyses are complete. Consequently, this must be explained in the proposal. There are some simplifications you might suggest by limiting the sizes and the temperature/pressure classes of piping system that MUST have comprehensive analysis. As NozzleTwister mentions, SOMETIMES you can estimate the number and type of pipe supports/hangers that will be needed from experience with VERY SIMILAR systems but to do that you really need to have much experience in pipe support design.

Certainly, you cannot arbitrarily choose a temperature below which all hangers will be of rigid type. Even using hanger spacing charts would provide dubious results. That is what doberdorks was suggesting, there are so many factors that MUST be known that estimating the number of spring hangers at the proposal stage is not possible.

So, the only thing you can do at the proposal stage is include words that describe the Codes to be used and the methodologies (e.g., software) that is to be used.

Regards, John.