What is the SIL level of a LINE_BREAK SYSTEM of a Pipeline Block valve

[billdoor]

Hello to All,

Can someone answer me about the SIL level of a LINE_BREAK SYSTEM of a Pipeline Block valve.

Or the line break system PFD generally used...

We need this for a SIL study related to a 48'' natural gas pipeline

Thank you

 

[mk3223]

Is it related to the SIS system per ISA84? I could be wrong, I thought the SIL level is determined according to the LOPA (Level of Protection Analysis) of the system.

 

[billdoor]

Hello,
Thank you for your reply mk3223.
I fact, The automatic pipeline valves would come with a built-in Automatic line-break detection and shutdown features. A gas-over-oil unit is used in this case.
My question is: What is the SIL rating of this type of automatic valves according to their manufacturers/vendors. Any past experience ??
The Line break system might be considered as a Safety Instrumented System
Sensor: Pressure drop over Time detection
Logic Control: Analysis of the gradient Pressure drop over Time detection, comparison with predetermined set point, Closing Decision
Final element: Automatic valve (natural gas pipeline)
I am wondering what the PFD Avg of the overall system would look like.
Are there some numbers around ??? Some Failure rates of ''line break system'' not working for 48'' auomatic pipeline valves handling natural gas.
If the manufacturer knows about the probability of Failure on Demand (PFD) of every single element of the ''whole line break system'', it will be easy to determine the overall PFD of the line break system and in the same way the SIL rating of the automatic pipeline valve with line break system their company would carry.

Thank you