I plan to use pneum control valve to function as safety shutdown isolation valve. This valve does not have solenoid. Within PID function block (DCS), is it possible to detect logic, and then drive the valve to become fully close by forcing MV value?

From safety perspective, is it reasonable?

Thanks in advance,

Josse

 

Why not use a safety rated isolation valve like a Ross valve instead?

 

Yes it is possible in DCS and you can use the pneumatic control valve to work as quick opening/ closing valve. But I would prefer to use a solenoid-operated on/ off pneumatic valve for safety shutdown application. Response time in the later case will be better.

Regards,
Amitabha Thakur

 

It depends on SIL( Safety Integrity Level ) of that function i.e closing valve based on some process condition. General practice is that safety and control cannot be combined. If you still wish to shutdown the control valve then, use solenoid valve, which will be output of ESD( Emergency shutdowm system). Honeywell DCS allows closing of valve by SHUTDOWN parameter through logic block.

Regards
Kamlesh Parmar
Honeywell, Canada