2 replies to this topic

[SawsanAli311]

Dear All, 

 

I would like to get your opinions on whether a tight shut off shutdown valve can be considered reliable enough for isolation in case maintenance is required to be carried out for an equipment located downstream this SDV. The SDV doesnt have a manual ball valve upstream or downstream for additional isolation.

If the SDV is Fail close status and even in case a command signal is sent to close the valve but the there is fault in the IA supply or electrical signal supply to the valve, the SDV will still remain close as it is FC. 

Additionally, this SDV is subject to a partial stroke test which ensures its meeting the required tightness .

 

Hence, considering all the above, can the SDV still be considered safe enough for isolation (when double block doesn't apply and positive isolation can be full filled at the  downstream vessel's side). 

[Bobby Strain]

Consider yourself as the person who performs the isolation. Then what is your opinion?

 

Bobby

[fallah]

 

I would like to get your opinions on whether a tight shut off shutdown valve can be considered reliable enough for isolation in case maintenance is required to be carried out for an equipment located downstream this SDV. The SDV doesnt have a manual ball valve upstream or downstream for additional isolation.

If the SDV is Fail close status and even in case a command signal is sent to close the valve but the there is fault in the IA supply or electrical signal supply to the valve, the SDV will still remain close as it is FC. 

Additionally, this SDV is subject to a partial stroke test which ensures its meeting the required tightness .

 

Hence, considering all the above, can the SDV still be considered safe enough for isolation (when double block doesn't apply and positive isolation can be full filled at the  downstream vessel's side). 

 

Hi,

 

In general a SDV with TSO characteristic is  reliable enough for isolation of SDV upstream from its downstream; but in the case maintenance is required to be carried out for an equipment located downstream this SDV, positive isolation is highly required to be provided between SDV and downstream equipment.