2 replies to this topic

[SawsanAli311]

Dear All,

I would like to seek your views on the following:

- Requirement for full bore isolation valves at PSV inlet.. ASME SEC VIII recommends them to be full bore by stating'' full area stop valves'' . While API 520 Part II removed this requirement in its latest revision.
- Requirement for FB isolation valves downstream the PSV
- Requirement for full bore isolation valves downstream the restriction orifice which is on emergency blowdown valves.

Thanks

Regards,

[breizh]

Hi ,

http://webwormcpt.bl...-spare-psv.html

 

Consider the link above to support your work , please read it carefully ( 2 PSV, isolation valves , car seal ,100% flow path, etc ) 

 

Breizh  

Edited by breizh, 10 December 2019 - 02:32 AM.

[Chemitofreak]

My two cents:

 

The reason for using Full Bore valve for isolation of PSV

 

1) Low pressure drop

 

2) Allows no liquid pocket formation in the piping