Pipe shoe guide unbalance 3

[simplemath]

When walking down piping,what caused my attention is pipe shoe guide unbalance. Pipe shoe is standard from PT&P.
Pipe lateral movement is limited by T-shape welded to structure. Piping stress analysis requested each side 1/4".
But as-built pipe shoe is not centered with one side 1/8"- and the other side 3/8"+. Pipe fitter said this is an accepted installation as long as both gap added up to 1/2" which is equal to the sum of designed gap.

I am asking is this OK in general practice?

Thanks.

 

[DSB123]

meanstone,
I assume you are talking about "gaps" between the pipe shoe and the guide steel. Normal gaps are 3mm (either side) but 6mm may be the "standard" for the particular design house. In general if the pipe is over to one side then this would be acceptable for long straight runs of piping where the guide is to limit excessive lateral movement of the piping. However if the guide is close to a piece of strain sensitive equipment where the gap has been designed to be there to limit loads on the equipment then you could have a problem if free expansion is restricted.

 

[RossABQ]

If the gap was required to be equal, it should have been explicitly called out on the drawings, at a specified system condition (i.e., a specific temperature and pressure). The gaps will not be equal at all conditions or the gap could be spec'd as zero.

 

[UtilityLouie]

Also:

If the system was hot or had been operated to temperature and cooled down... it might've not came back to dead center.

If you're around a critical piece of equipment that requires the correct gaps to minimize nozzle stress, the gap and what side it's on is critical.

Remember too that when the loads from the stress analysis program were given to the structural engineer to re-check the member sizing on the rack steel or other support steel, the load was calculated based on the pipe moving that 1/4" and THEN getting restrained. If the gap is less than that 1/4", the forces will be higher.

 

[Cuemaster64]

Meanstone,

As a steamfitter now in QC your question as answered by your fitter is okay. In the field we would put the pipe on its coordinates and attach the guides as per standard request. On my site the gap is usually 3mm as stated in an attached thread. Exceptions to this standard are noted on our isometrics (eg. "zero gap"). As an ispector walking down a line I would let this pass.

Hope this helps.

 

[DSB123]

UtilityLouie,
"If you're around a critical piece of equipment that requires the correct gaps to minimize nozzle stress, the gap and what side it's on is critical."

Is this not what I replied ??