Definition:
Fail Safe (as in FS valve)
Subject Area 1:
Drilling & Operations
Remarks:
Fail Safe: Some control valves, particularly those associated with shut down system, are designed so that if their motivating force (electricity, instrument air, instrument gas, hydraulic pressure, etc.) should fail, the valve itself will either positively open or positively close. The selection of opening or closing is based on the safest position for the system in which that valve is installed. Thus the valve will fail in the safe position or will fail safe.