Fail closed (FC), arrow form
ISA 5.1 (actuator action on failure)
Drawn as
A control valve with a downward arrowhead drawn on the stem between body and actuator.
Meaning
On loss of air, power or signal the valve goes fully closed. Typical for ESD valves, feed and fuel valves. It is a property of the valve (set its fail action to FC), not a separate item.
Variants
- The letter form writes the letters below the body instead
- The bar forms for FL/FI come from secondary sources describing ISA 5.1 and are less widely used than the letters; check the legend
- On 3-way valves, arrows on the ports show the failed flow path
Tags
FC
Not physical hardware. Read it, then skip it in the 3D model.