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Pipe strain measurement during installation

Pipe strain measurement during installation

Pipe strain measurement during installation

(OP)
We are installing lobe blowers. Per API686 we have measured and confirmed that no undue pipe load is passed on to the blower casing.

However, blower has an inlet and and out let silencers. And silencers are attached with plant piping.

Doubt is if we have to carry out pipe strain measurement while aligning shop piping to the silencers too.  

RE: Pipe strain measurement during installation

We require that all piping bolted to rotating machinery is checked for pipe alignment and pipe strain.  Even if the particular type of equipment does not have clearly defined nozzle load limits, excessive pipe strain should be avoided.  As a minimum, we require that dial indicator installed across the coupling show less than 0.002 inch movement in any direction when the piping is bolted up.  The preferred way to verify this is to bolt up all piping up to the first flange, and then monitor as the final connection to the machine is made up.  

If the flanges you are describing are back away from the compressor, they could still be relevant.  We do not require a pipe strain check for flanges that are far enough away from the machine that they are beyond the first rigid pipe support.  But, for anything inside the first rigid support, pipe strain must be checked.   

Johnny Pellin

RE: Pipe strain measurement during installation

(OP)
Thanks a lot JJPellin!

Actually, silencers are rigidly supported on the blower skid, while the pipe on the silencer is getting connected to the silencer on the outlet flange of the silencer is within the rigid support., so what is your opinion?

Please let me know..

RE: Pipe strain measurement during installation

(OP)
In the meanwhile is this fact ( for anything inside the first rigid support, pipe strain must be checked) is available in any standard / practice or any other reference document please?  

RE: Pipe strain measurement during installation

Skids are not perfectly rigid, and their foundations have been known to settle.  Plant piping moves around too.  So even if you can make up the system without undue stress on the skid mounted components, it may not stay that way.

For that reason, I personally would be inclined to use compensators, or some relatively flexible piping, between the blower and the silencers, and between the silencers and the mill piping, whether required by standards or not.


 

Mike Halloran
Pembroke Pines, FL, USA

RE: Pipe strain measurement during installation

(OP)
Mike, Thanks a lot... I completely agree with you that everything DONT HAVE TO be per standard.

However, JJpellin has a valid, very focused reply to the question, informing us how important it is to conduct a pipe strain on flanges especially when flanges are within a rigid support.

Now My only doubt is the flange in question is on the silencer and the silencer base rigidly supported and connected to blower thru a flex.  

RE: Pipe strain measurement during installation

I do not have a reference to an industry standard to require pipe strain checks as I described.  This requirement is an internal standard for our plant.  

If the blower is delivered as a skid unit, I would check for pipe strain when bolting up the piping to the silencers even if the silencers are rigidly supported to the skid base.  The check is quick and easy.  If the rigid mounting on the skid is done well, the blower should not move.  If the blower does move, either the pipe strain is excessive or the rigid mounting to the skid is inadequate. In either case, I would prefer to know so I could address it.
 

Johnny Pellin

RE: Pipe strain measurement during installation

(OP)
JJpellin/Mike Thanks so much for your Techical support. I really appreciate for giving a clear picture.
Take care!

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