4 replies to this topic

[Engineer87]

Hi Members,

 

I have expansion bottle served as an safety feature on the skid.Our maximum line design pressure is far greater than operating pressure so little confused is it still sized for blocked flow?.

 

 

Attached is the snapshot.

 

 

Thanks

Attached Files

•  Capture.JPG   20.67KB   10 downloads

[fallah]

Engineer87,

 

The main point is the source pressure value respect to downstream design pressure. If the source pressure is higher, then the blocked outlet should be among credible scenarios of the downstream PSV...

[Engineer87]

No, source pressure is not greater then our design pressure.Fire scenario will be a credible case in this regard then?

[pleckner]

The difference between your maximum operating pressure and the line design pressure is irrelevant.

 

If this is a liquid-filled line that can be blocked in and then be stagnant for a period of time, then you will most likely exceed design pressure in a thermal expansion scenario and this arrangement is to protect against that.

 

I can't tell from your snapshot but If there is a control valve upstream where the upstream piping is at a higher design pressure than the line you show, then you could protect the line shown with this arrangement.

 

Fire scenario for a line only is not typically considered unless you are really concerned about some very bad nasty getting out. 

[fallah]

Engineer87,

 

As Phil rightly pointed out fire case isn't typically credible for a line only. A TSV is required if there is potential for thermal expansion for blocked-in liquid. A PSV may be required if piping segment which is exposed to fire included more than, let say, 2-3 tons  flammable gas, liquid HC or liquefied HC...Obviously if both thermal expansion and fire cases are credible scenarios installing a PSV would be enough...