SIF for shoes

Posted by: M.Mohammad

SIF for shoes - 02/26/13 09:42 AM

Dear friends,
I was wondering if someone say me about SIF of shoes if any.
Should we use any SIF for that? If yes, how much? If not, why?
Posted by: Goodness

Re: SIF for shoes - 03/02/13 12:08 PM

Hello,
there is no SIF for shoes,

Pipe shoe should be selected correctly respect to pipe diameter size,
refer to support drawing and select proper shoe.

Good luck
Posted by: Kira06

Re: SIF for shoes - 05/19/13 02:48 AM

I just want to ask the same question, why does in pipe shoe we do not
Put SIF? And also, how do we consider the clamp stool support
for galvanized piping? Sif considerations? Thanks!
Posted by: Richard Ay

Re: SIF for shoes - 05/19/13 09:07 AM

A "shoe" is not a pipe fitting (elbow, tee). You didn't alter the pipe pressure boundary.
Posted by: Jop

Re: SIF for shoes - 05/19/13 01:52 PM

Q. Why do we consider the clamp stool support for galvanized piping?

A. You should not weld on Galvanized piping (or other surfaces) because the heat/flame of welding reacts with the zinc in the galvanizing and forms a gas that is harmful to the health of the welder and could cause death.
Posted by: Kira06

Re: SIF for shoes - 06/04/13 09:02 AM

Hi Richard!

Thank you for your response. But would you mind elaborating it further?


----------------

Jop,

My question is how do we consider in caesar the clamp stool? Do we need to model it the same as trunnion/dummy with SIf?

Thanks!
Posted by: Richard Ay

Re: SIF for shoes - 06/05/13 11:53 PM

Kira,

Take a look at the fittings in Appendix D of B31.1 or B31.3. These are the fittings that were tested and to which the concept of SIFs apply. Notice there are no "shoes" here.
Posted by: MONTEK99

Re: SIF for shoes - 06/16/13 06:21 PM

Kira,
Regarding support SIF you are asking about, the support analysis is a different part which is generally carried out by support group in FEA or the similar software. Some companies may not have specially allocated support group, but any how they have designed specific supports for specific loading & pipe size. This you can find in support spec in the form of allowable loads on the weakest part of the support assembly. Also allowable loads in particular direction i.e. longitudinal (axial), lateral (loads on guides) & of course vertical load are given.
The purpose of telling all these things is that, when a support engineer derives these loads, he has already taken care of all these stress intensifying factors due to the geometry of the support assembly.
Therefore what remains to our side is the analysis of pipe treating support as rigid (normally) or in some extensive analyses with actual support stiffness (composite analysis case). Of course a stress engg. should cross check the loads coming on supports with the allowables from support spec.
In case of trunion, we weld it to pipe directly so making it as an integral part of it, so it becomes mandatory to consider SIF at that point.
I hope this will clear the things.
Thanks/Salamat.